爆破型和聚能型装药水下爆炸载荷特性

Blasting and shaped charges are the main forms of underwater weapons,and their near-field underwater explosions(UNDEX)can severely damage structures.Therefore,it is of great importance to study underwater explosive load characteristics of different forms of charges.The full physical process of a typical underwater explosion of a sphere/column blasting charge and a shaped charge was simulated using the Eulerian method.The loading characteristics of the underwater blast shock wave and bubble,as well as the projectile,were studied.The results show that the shock wave loads of spherical,cylindrical,and polygonal charges propagate outward in spherical,ellipsoidal–spherical and ellipsoidal–spherical wavefronts,respectively.When the shock wave reaches 16 times the distance-to-diameter ratio,its surface is approximately spherical.In addition,in the shaped charge underwater explosion,the shaped charge liner cover absorbs 30°–90°of the shock wave energy and some of the bubble energy to form a high-speed shaped penetrator.Spherical,ellipsoidal,and ellipsoidal bubbles are generated by underwater explosions of spherical,cylindrical,and shaped charges,respectively.The obtained results provide a reference for evaluating the power of underwater weapons.

Oxygenation,inflammatory response and lung injury during one lung ventilation in rabbits using inspired oxygen fraction of 0.6 vs.1.0

Maintaining adequate oxygenation during one-lung ventilation（OLV） requires high inspired oxygen fraction（FiO_2）.However,high FiO_2 also causes inflammatory response and lung injury.Therefore,it remains a great interest to clinicians and scientists to optimize the care of patients undergoing OLV.The aim of this study was to determine and compare oxygenation,inflammatory response and lung injury during OLV in rabbits using FiO_2 of 0.6 vs.1.0.After 30 minutes of two-lung ventilation（TLV） as baseline,30 rabbits were randomly assigned to three groups receiving mechanical ventilation for 3 hours：the sham group,receiving TLV with 0.6 FiO_2;the 1.0 FiO_2 group,receiving OLV with 1.0 FiO_2;the 0.6 FiO_2 group,receiving OLV with 0.6 FiO_2.Pulse oximetry was continuously monitored and arterial blood gas analysis was intermittently conducted.Histopathologic study of lung tissues was performed and inflammatory cytokines and the mRNA and protein of nuclear factor kappa B（NF-κB） p65 were determined.Three of the 10 rabbits in the 0.6 FiO_2 group suffered hypoxemia,defined by pulse oximetric saturation（SpO_2） less than 90%.Partial pressure of oxygen（PaO_2）,acute lung injury（ALI） score,myeloperoxidase（MPO）,tumor necrosis factor-a（TNF-α）,interleukin-6（IL-6）,mRNA and protein of NF-kB p65 were lower in the 0.6 FiO_2group than in the 1.0 FiO_2 group.In conclusion,during OLV,if FiO_2 of 0.6 can be tolerated,lung injury associated with high FiO_2 can be minimized.Further study is needed to validate this finding in human subjects.

Viromes of Haemaphysalis longicornis reveal different viral abundance and diversity in free and engorged ticks

Haemaphysalis longicornis ticks,commonly found in East Asia,can transmit various pathogenic viruses,includingthe severe fever with thrombocytopenia syndrome virus(SFTSV)that has caused febrile diseases among humansin Hubei Province.However,understanding of the viromes of H.longicornis was limited,and the prevalence ofviruses among H.longicornis ticks in Hubei was not well clarified.This study investigates the viromes of bothengorged(fed)and free(unfed)H.longicornis ticks across three mountainous regions in Hubei Province from 2019to 2020.RNA-sequencing analysis identified viral sequences that were related to 39 reference viruses belonging tounclassified viruses and seven RNA viral families,namely Chuviridae,Nairoviridae,Orthomyxoviridae,Parvoviridae,Phenuiviridae,Rhabdoviridae,and Totiviridae.Viral abundance and diversity in these ticks were analysed,andphylogenetic characteristics of the Henan tick virus(HNTV),Dabieshan tick virus(DBSTV),Okutama tick virus(OKTV),and Jingmen tick virus(JMTV)were elucidated based on their full genomic sequences.Prevalenceanalysis demonstrated that DBSTV was the most common virus found in individual H.longicornis ticks(12.59%),followed by HNTV(0.35%),whereas JMTV and OKTV were not detected.These results improve our understanding of H.longicornis tick viromes in central China and highlight the role of tick feeding status and geographyin shaping the viral community.The findings of new viral strains and their potential impact on public health raisethe need to strengthen surveillance efforts for comprehensively assessing their spillover potentials.

Transcription factor EHF interacting with coactivator AJUBA aggravates malignancy and acts as a therapeutic target for gastroesophageal adenocarcinoma

Transcriptional dysregulation of genes is a hallmark of tumors and can serve as targets for cancer drug development.However,it is extremely challenging to develop small-molecule inhibitors to target abnormally expressed transcription factors(TFs)except for the nuclear receptor family of TFs.Little is known about the interaction between TFs and transcription cofactors in gastroesophageal adenocarcinoma(GEA)or the therapeutic effects of targeting TF and transcription cofactor complexes.In this study,we found that ETS homologous factor(EHF)expression is promoted by a core transcriptional regulatory circuitry(CRC),specifically ELF3-KLF5-GATA6,and interference with its expression suppressed the malignant biological behavior of GEA cells.Importantly,we identified Ajuba LIM protein(AJUBA)as a new coactivator of EHF that cooperatively orchestrates transcriptional network activity in GEA.Furthermore,we identified KRAS signaling as a common pathway downstream of EHF and AJUBA.Applicably,dual targeting of EHF and AJUBA by lipid nanoparticles cooperatively attenuated the malignant biological behaviors of GEA in vitro and in vivo.In conclusion,EHF is upregulated by the CRC and promotes GEA malignancy by interacting with AJUBA through the KRAS pathway.Targeting of both EHF and its coactivator AJUBA through lipid nanoparticles is a novel potential therapeutic strategy.

服务学校 做好支撑——北京科技大学大学英语教学方案

本文从大学英语教学简要说明、教学目标、教学体系、课程设置、评价体系、教学管理以及相关资料附录七个方面介绍了北京科技大学大学英语教学方案,突出北京科技大学大学英语教学'服务学校,做好支撑'的校本特色。

融合信息技术与教育教学,推进以学为本的大学英语教学方式变革

以学为本的大学英语课堂教学对教学双方都提出了更高的要求和挑战,信息技术与教育教学的深度融合,为以学为本的大学英语教学方式变革落到实处提供了新的路径。深度融合信息技术与大学英语课堂教学,拓展课堂时空、变应试课堂为应用课堂、变被动学习为参与式学习、变个体学习为协作学习、拓展课堂学习为泛在学习,实现了传统以教为本的课堂向以学为本的混合式课堂的转变,为有效解决以学为本大学英语课堂教学遭遇的困境提供了可资借鉴的新途径。

Genomic insights into the origin, adaptive evolution, and herbicide resistance of Leptochloa chinensis, a devastating tetraploid weedy grass in rice fields

Chinese sprangletop (Leptochloa chinensis), belonging to the grass subfamily Chloridoideae, is one of the most notorious weeds in rice ecosystems. Here, we report a chromosome-scale reference genome assembly and a genomic variation map of the tetraploid L. chinensis. The L. chinensis genome is derived from two diploid progenitors that diverged ∼10.9 million years ago, and its two subgenomes display neither fractionation bias nor overall gene expression dominance. Comparative genomic analyses reveal substantial genome rearrangements in L. chinensis after its divergence from the common ancestor of Chloridoideae and, together with transcriptome profiling, demonstrate the important contribution of tetraploidization to the gene sources for the herbicide resistance of L. chinensis. Population genomic analyses of 89 accessions from China reveal that L. chinensis accessions collected from southern/southwestern provinces have substantially higher nucleotide diversity than those from the middle and lower reaches of the Yangtze River, suggesting that L. chinensis spread in China from the southern/southwestern provinces to the middle and lower reaches of the Yangtze River. During this spread, L. chinensis developed significantly increased herbicide resistance, accompanied by the selection of numerous genes involved in herbicide resistance. Taken together, our study generated valuable genomic resources for future fundamental research and agricultural management of L. chinensis, and provides significant new insights into the herbicide resistance as well as the origin and adaptive evolution of L. chinensis.

Synthesis of porous carbon spheres derived from lignin through a facile method for high performance supercapacitors

Porous carbon spheres（PCS） derived from lignin have been prepared through a facile method and fabricated as electrodes for electric double-layer capacitors. Spherical shaped mixtures of lignosulfonate and crystalized KOH are formed by spray drying of a solution of lignosulfonate and KOH. Activation by KOH is performed at high temperatures along with lignosulfonate carbonization. With an appropriate pore structure, the obtained PCS have a specific surface area of 1372.87 m^2 g^-1 and show a capacitance of 340 F g^-1 in 3 M KOH at a current density of 0.5 A g^-1. Moreover, a symmetric supercapacitor fabricated using the PCS as electrodes show a maximum capacitance of 68.5 F g^-1, and an energy density of 9.7 W h kg^-1 at a power density of 250 W kg^-1. The capacity retention is more than 94.5% after 5000 galvanostatic chargedischarge cycles. The excellent characteristics seem to be ascribed to the pore structures of PCS that have a large specific surface area and a low electrical resistance.

Design of coherent wideband radiation process in a Nd3+-doped high entropy glass system

We discover that the spatially coherent radiation within a certain frequency range can be obtained without a common nonlinear optical process.Conventionally,the emission spectra were obtained by de-exciting excited centers from real excited energy levels to the ground state.Our findings are achieved by deploying a high-entropy glass system(HEGS)doped with neodymium ions.The HEGS exhibits a much broader infrared absorption than common glass systems,which can be attributed to be high-frequency optical branch phonons or allowable multi-phonon processes caused by phonon broadening in the system.A broadened phonon-assisted wideband radiation(BPAWR)is induced if the pump laser is absorbed by the system.The subsequent low-threshold self-absorption coherence modulation(SACM)can be controlled by changing excitation wavelengths,sample size,and doping concentrations.The SACM can be red-shifted through the emission of phonons of the excited species and be blue-shifted by absorbing phonons before they are de-excited.There is a time delay up to 1.66 ns between the pump pulse and the BPAWR when measured after traveling through a 35 mm long sample,which is much longer than the Raman process.The BPAWR-SACM can amplify the centered non-absorption band with a gain up to 26.02 dB.These results reveal that the shift of the novel radiation is determined by the frequency of the non-absorption band near the absorption region,and therefore the emission shifts can be modulated by changing the absorption spectrum.When used in fiber lasers,the BPAWR-SACM process may help to achieve tunability.

Trends on medicine use in county public hospitals in Sanming,China from 2011 to 2017

Sanming model in healthcare reform has attracted much attention due to its comprehensive and efficient exploration,while its impact on physicians’prescribing behavior remains unknown.In the present study,we aimed to evaluate the impact of Sanming reform on physicians’medicine use in county-level public hospitals.We collected outpatient prescriptions in the internal medicine and pediatric departments from nine county public hospitals in Sanming from January 2011 to December 2017.We used six prescribing indicators to analyze physicians’medicine use.The Mann-Kendall test was used to examine trends in the study outcomes.A total of 1577904 outpatient prescriptions were included in this study.The average prescription rate of antibiotics and combined antibiotics were 57.5%and 12.2%in 2011,respectively,which were declined to 28.2%(P=0.007)and 2.9%(P=0.003)in 2017,respectively.The average prescription rate of injection was 30.2%in 2011 and declined to 5.3%(P=0.003)in 2017.As for the subgroup analysis of the internal medicine and pediatric departments,the average prescription rate of antibiotics was 39.3%and 71.4%in 2011,respectively,which was declined to 10.2%(P=0.003)and 47.3%(P=0.035)in 2017,respectively.The average prescription rate of combined antibiotics was 15.9%and 9.4%in 2011,respectively,which was declined to 2.9%(P=0.003)and 2.9%(P=0.016),respectively.The average prescription rate of injection was 17.8%and 39.6%in 2011,respectively,which was declined to 1.9%(P=0.003)and 9.0%(P=0.003),respectively.Our study showed a significant decreasing trend in antibiotic use in county-level public hospitals after the Sanming healthcare reform,indicating that the reform successfully promoted the appropriate use of medicine to some extent.

Potassium ion pre‑intercalated MnO_(2)for aqueous multivalent ion batteries

Manganese dioxide(MnO_(2)),as a cathode material for multivalent ion(such as Mg^(2+)and Al^(3+))storage,is investigated due to its high initial capacity.However,during multivalent ion insertion/extraction,the crystal structure of MnO_(2)partially collapses,leading to fast capacity decay in few charge/discharge cycles.Here,through pre-intercalating potassium-ion(K+)intoδ-MnO_(2),we synthesize a potassium ion pre-intercalated MnO_(2),K_(0.21)MnO_(2)·0.31H_(2)O(KMO),as a reliable cathode material for multivalent ion batteries.The as-prepared KMO exhibits a high reversible capacity of 185 mAh/g at 1 A/g,with considerable rate performance and improved cycling stability in 1 mol/L MgSO_(4)electrolyte.In addition,we observe that aluminum-ion(Al^(3+))can also insert into a KMO cathode.This work provides a valid method for modifcation of manganesebased oxides for aqueous multivalent ion batteries.

Coordination of EZH2 and SOX2 specifies human neural fate decision

Polycomb repressive complexes(PRCs)are essential in mouse gastrulation and specify neural ectoderm in human embryonic stem cells(hESCs),but the underlying molecular basis remains unclear.Here in this study,by employing an array of different approaches,such as gene knock-out,RNA-seq,ChIP-seq,et al.,we uncover that EZH2,an important PRC factor,specifies the normal neural fate decision through repressing the competing meso/endoderm program.EZH2^(−/−)hESCs show an aberrant re-activation of meso/endoderm genes during neural induction.At the molecular level,EZH2 represses meso/endoderm genes while SOX2 activates the neural genes to coordinately specify the normal neural fate.Moreover,EZH2 also supports the proliferation of human neural progenitor cells(NPCs)through repressing the aberrant expression of meso/endoderm program during culture.Together,our findings uncover the coordination of epigenetic regulators such as EZH2 and lineage factors like SOX2 in normal neural fate decision.