Dynamically triggered seismicity on a tectonic scale:A review

Earthquakes triggered by dynamic disturbances have been confirmed by numerous observations and experiments.In the past several decades,earthquake triggering has attracted increasing attention of scholars in relation to exploring the mechanism of earthquake triggering,earthquake prediction,and the desire to use the mechanism of earthquake triggering to reduce,prevent,or trigger earthquakes.Natural earthquakes and large‐scale explosions are the most common sources of dynamic disturbances that trigger earthquakes.In the past several decades,some models have been developed,including static,dynamic,quasi‐static,and other models.Some reviews have been published,but explosiontriggered seismicity was not included.In recent years,some new results on earthquake triggering have emerged.Therefore,this paper presents a new review to reflect the new results and include the content of explosion‐triggered earthquakes for the reference of scholars in this area.Instead of a complete review of the relevant literature,this paper primarily focuses on the main aspects of dynamic earthquake triggering on a tectonic scale and makes some suggestions on issues that need to be resolved in this area in the future.

Benzo[4,5]imidazo[1,2-a]pyrimidine-based structure-inherent targeting fluorescent sensor for imaging lysosomal viscosity and diagnosis of lysosomal storage disorders

Benzo[4,5]imidazo[1,2-a]pyrimidine-based derivatives play crucial roles in medicines,pesticides,tracers and photoelectric materials.However,their synthesis approach still needs to be optimized,and their fluorescent properties in intracellular microenvironment are unclear.Here,a Cu(II)-catalyzed cascade coupling cyclization reaction was successfully developed to synthesize benzo[4,5]imidazo[1,2-a]pyrimidine scaffold with mild reaction conditions,broad substrate scopes and high yields.After a system study,we found that compound 4aa displayed an optimal viscosity-specific response with remarkable fluorescence enhancement(102-fold)for glycerol at 490 nm.Particularly,4aa possessed excellent structure-inherent targeting(SIT)capability for lysosome(P=0.95)with high p H stability and large Stokes shift.Importantly,4aa was validated for its effectiveness in diagnosing lysosomal storage disorders(LSD)in living cells.The 4aa also showed its potential to map the micro-viscosity and its metabolism process in zebrafish.This work not only affords an efficient protocol to fabricate benzo[4,5]imidazo[1,2-a]pyrimidine derivatives,reveals this skeleton has excellent SIT features for lysosome,but also manifests that 4aa can serve as a practical tool to monitor lysosomal viscosity and diagnose LSD.

A prospective cohort study on serum A20 as a prognostic biomarker of aneurysmal subarachnoid hemorrhage

BACKGROUND:A20 may be a neuroprotective factor.Herein,we aimed to investigate whether serum A20 levels were associated with disease severity,delayed cerebral ischemia(DCI),and outcome after aneurysmal subarachnoid hemorrhage(aSAH).METHODS:In this prospective cohort study containing 112 aSAH patients and 112 controls,serum A20 levels were quantified.At 90 d poststroke,Modified Rankin Scale(MRS) scores≥3 were defined as a poor outcome.All correlations and associations were assessed using multivariate analysis.RESULTS:Compared with controls,there was a significant elevation of serum A20 levels in patients(median 123.7 pg/mL vs.25.8 pg/mL;P<0.001).Serum A20 levels were independently correlated with Hunt-Hess scores(β 9.854;95% confidence interval [95% CI] 2.481-17.227,P=0.009) and modified Fisher scores(β 10.349,95% CI 1.273-19.424,P=0.026).Independent associations were found between serum A20 levels and poor outcome(odds ratio [OR] 1.015,95%CI 1.000-1.031,P=0.047) and DCI(OR 1.018,95% CI 1.001-1.035,P=0.042).Areas under the curve for predicting poor outcome and DCI were 0.771(95% CI 0.682-0.845) and 0.777(95% CI 0.688-0.850),respectively.Serum A20 levels ≥128.15 pg/mL predicted poor outcome,with a sensitivity of 73.9% and specificity of 74.2%,and A20 levels ≥160.55 pg/mL distinguished the risk of DCI with65.5% sensitivity and 89.2% specificity.Its ability to predict poor outcome and DCI was similar to those of Hunt-Hess scores and modified Fisher scores(both P>0.05).CONCLUSION:Enhanced serum A20 levels are significantly associated with stroke severity and poor clinical outcome after aSAH,implying that serum A20 may be a potential prognostic biomarker for aSAH.

Investigation on the physical mechanism of cavity percentage dependent shear strength for rock joints considering the real contact joint surface

To explain the effect of joint roughness on joint peak shear strength(JPSS)and investigate the effect of different contact states of joint surface on JPSS,we try to clarify the physical mechanism of the effect of joint cavity percentage(JCP)on JPSS from the perspective of the three-dimensional(3D)distribution characteristics of the actual contact joint surface,and propose a JPSS model considering the JCP.Shear tests for red sandstone joints with three different surface morphologies and three different JCPs were performed under constant normal load condition.Based on test fitting results,the reduction effect of the JCP on JPSS is investigated,and a JPSS model for cavity-containing joints is obtained.However,the above model only considers the influence of JCP by fitting test data,and does not reveal the physical mechanism of JCP affecting the JPSS.Based on the peak dilation angle model for consideration of the actual contact joint morphology,and the influence of JCP on the roughness of the actual contact joint surface,a theoretical model of the JPSS considering the JCP is proposed.The derivation process does not depend on the test fitting,but is entirely based on the joint mechanical law,and its physical significance is clear.It is proposed that the essence of the influence of the JCP on JPSS is that the JCP first affects the normal stress of the actual contact joints,further affects the roughness of actual contact joints,and then affects the shear strength.

Aphamines A-C,dimeric acyclic diterpene enantiomers from Aphanamixis polystachya

Aphamines A-C(1-3),three pairs of acyclic diterpene dimer enantiomers with an unprecedent ploymerization pattern,were discovered from Aphanamixis polystachya by NMR-guided isolation and chiral resolution.The elucidation of their novel carbon skeletons was achieved based on spectroscopic analysis,exciton chirality,and calculated electronic circular dichroism(ECD).Plausible Claisen rearrangement,5-exo-trig cyclization,and reduction reactions may play important roles in the polymeric biosynthesis pathway.Compounds 1 and 3 showed inhibitory effects on nitric oxide(NO)production(IC_(50):6.71-15.36 μmol/L) and reduced the expression of iNOS in LPS-induced RAW 264.7 macrophages.