To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers i...To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,Xinjiang.By changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles.The research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation pattern.The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal characteristics.Furthermore,a positive correlation between the correlation dimension and the bedding dip angle was observed.When the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the specimen.By analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen failure.This study provides theoretical references for understanding the failure patterns of volcanic rock.展开更多
Background Guidelines recommend that all patients with upper gastrointestinal bleeding(UGIB)undergo endoscopy within 24 h.It is unclear whether a subgroup may benefit from an urgent intervention.We aimed to evaluate t...Background Guidelines recommend that all patients with upper gastrointestinal bleeding(UGIB)undergo endoscopy within 24 h.It is unclear whether a subgroup may benefit from an urgent intervention.We aimed to evaluate the influence of endoscopic hemostasis and urgent endoscopy on mortality in UGIB patients with high-risk stigmata(HRS).Methods Consecutive patients with suspected UGIB were enrolled in three Japanese hospitals with a policy to perform endoscopy within 24 h.The primary outcome was 30-day mortality.Endoscopic hemostasis and endoscopy timing(urgent,6h;early,>6h)were evaluated in a regression model adjusting for age,systolic pressure,heart rate,hemoglobin,creatinine,and variceal bleeding in multivariate analysis.A propensity score of 1:1 matched sensitivity analysis was also performed.Results HRS were present in 886 of 1966 patients,and 35 of 886(3.95%)patients perished.Median urgent-endoscopy time(n=769)was 3.0h(interquartile range[IQR],2.0–4.0 h)and early endoscopy(n紏117)was 12.0h(IQR,8.5–19.0 h).Successful endoscopic hemostasis and urgent endoscopy were significantly associated with reduced mortality in multivariable analysis(odds ratio[OR],0.22;95%confidence interval[CI],0.09–0.52;P=0.0006,and OR,0.37;95%CI,0.16–0.87;P=0.023,respectively).In a propensity-score-matched analysis of 115 pairs,adjusted comparisons showed significantly lower mortality of urgent vs early endoscopy(2.61%vs 7.83%,P<0.001).Conclusions A subgroup of UGIB patients,namely those harboring HRS,may benefit from endoscopic hemostasis and urgent endoscopy rather than early endoscopy in reducing mortality.Implementing triage scores that predict the presence of such lesions is important.展开更多
In eukaryotes,histone acetylation is a major modification on histone N-terminal tails that is tightly connected to transcriptional activation.HDA6 is a histone deacetylase involved in the transcriptional regulation of...In eukaryotes,histone acetylation is a major modification on histone N-terminal tails that is tightly connected to transcriptional activation.HDA6 is a histone deacetylase involved in the transcriptional regulation of genes and transposable elements(TEs)in Arabidopsis thaliana.HDA6 has been shown to participate in several complexes in plants,including a conserved SIN3 complex.Here,we uncover a novel protein complex containing HDA6,several Harbinger transposon-derived proteins(HHP1,SANT1,SANT2,SANT3,and SANT4),and MBD domain-containing proteins(MBD1,MBD2,and MBD4).We show that mutations of all four SANT genes in the sant-null mutant cause increased expression of the flowering repressors FLC,MAF4,and MAF5,resulting in a late flowering phenotype.Transcriptome deep sequencing reveals that while the SANT proteins and HDA6 regulate the expression of largely overlapping sets of genes,TE silencing is unaffected in sant-null mutants.Our global histone H3 acetylation profiling shows that SANT proteins and HDA6 modulate gene expression through deacetylation.Collectively,our findings suggest that Harbinger transposon-derived SANT domain-containing proteins are required for histone deacetylation and flowering time control in plants.展开更多
Analysis of the data suggests that the biophysical radiophysical sensing future earthquake epicenters is a promising direction for the medium-term and short-term forecasting of seismic events. We believe that it is ne...Analysis of the data suggests that the biophysical radiophysical sensing future earthquake epicenters is a promising direction for the medium-term and short-term forecasting of seismic events. We believe that it is necessary to create an international network of seismic monitoring biophysical for all seismically active areas of the globe. Information about biophysical precursors of earthquakes should be accumulated in the computer center, and operating information transmitted to all peripheral seismic monitoring station biophysical and services Ministry of Emergencies. In conclusion, I emphasize the value of such a centralized system of control over the “breath” of the Earth for the prevention and the prevention of industrial accidents in the mines, road transport, large power plants, etc.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.52174096,42277174).
文摘To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,Xinjiang.By changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles.The research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation pattern.The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal characteristics.Furthermore,a positive correlation between the correlation dimension and the bedding dip angle was observed.When the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the specimen.By analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen failure.This study provides theoretical references for understanding the failure patterns of volcanic rock.
文摘Background Guidelines recommend that all patients with upper gastrointestinal bleeding(UGIB)undergo endoscopy within 24 h.It is unclear whether a subgroup may benefit from an urgent intervention.We aimed to evaluate the influence of endoscopic hemostasis and urgent endoscopy on mortality in UGIB patients with high-risk stigmata(HRS).Methods Consecutive patients with suspected UGIB were enrolled in three Japanese hospitals with a policy to perform endoscopy within 24 h.The primary outcome was 30-day mortality.Endoscopic hemostasis and endoscopy timing(urgent,6h;early,>6h)were evaluated in a regression model adjusting for age,systolic pressure,heart rate,hemoglobin,creatinine,and variceal bleeding in multivariate analysis.A propensity score of 1:1 matched sensitivity analysis was also performed.Results HRS were present in 886 of 1966 patients,and 35 of 886(3.95%)patients perished.Median urgent-endoscopy time(n=769)was 3.0h(interquartile range[IQR],2.0–4.0 h)and early endoscopy(n紏117)was 12.0h(IQR,8.5–19.0 h).Successful endoscopic hemostasis and urgent endoscopy were significantly associated with reduced mortality in multivariable analysis(odds ratio[OR],0.22;95%confidence interval[CI],0.09–0.52;P=0.0006,and OR,0.37;95%CI,0.16–0.87;P=0.023,respectively).In a propensity-score-matched analysis of 115 pairs,adjusted comparisons showed significantly lower mortality of urgent vs early endoscopy(2.61%vs 7.83%,P<0.001).Conclusions A subgroup of UGIB patients,namely those harboring HRS,may benefit from endoscopic hemostasis and urgent endoscopy rather than early endoscopy in reducing mortality.Implementing triage scores that predict the presence of such lesions is important.
基金This work was supported by grants from the National Key Research and Development Program of China(2020YFE0202300)the Central Public-interest Scientific Institution Basal Research Fund,the BBSRC under the Grant Reference BB/P008569/1 to J.G.C.N.V.and E.dL.,and an Erasmus plus training award to L.G.
文摘In eukaryotes,histone acetylation is a major modification on histone N-terminal tails that is tightly connected to transcriptional activation.HDA6 is a histone deacetylase involved in the transcriptional regulation of genes and transposable elements(TEs)in Arabidopsis thaliana.HDA6 has been shown to participate in several complexes in plants,including a conserved SIN3 complex.Here,we uncover a novel protein complex containing HDA6,several Harbinger transposon-derived proteins(HHP1,SANT1,SANT2,SANT3,and SANT4),and MBD domain-containing proteins(MBD1,MBD2,and MBD4).We show that mutations of all four SANT genes in the sant-null mutant cause increased expression of the flowering repressors FLC,MAF4,and MAF5,resulting in a late flowering phenotype.Transcriptome deep sequencing reveals that while the SANT proteins and HDA6 regulate the expression of largely overlapping sets of genes,TE silencing is unaffected in sant-null mutants.Our global histone H3 acetylation profiling shows that SANT proteins and HDA6 modulate gene expression through deacetylation.Collectively,our findings suggest that Harbinger transposon-derived SANT domain-containing proteins are required for histone deacetylation and flowering time control in plants.
文摘Analysis of the data suggests that the biophysical radiophysical sensing future earthquake epicenters is a promising direction for the medium-term and short-term forecasting of seismic events. We believe that it is necessary to create an international network of seismic monitoring biophysical for all seismically active areas of the globe. Information about biophysical precursors of earthquakes should be accumulated in the computer center, and operating information transmitted to all peripheral seismic monitoring station biophysical and services Ministry of Emergencies. In conclusion, I emphasize the value of such a centralized system of control over the “breath” of the Earth for the prevention and the prevention of industrial accidents in the mines, road transport, large power plants, etc.
