The mortise and tenon structure enabling lamellar carbon composites of ultra-high bending strength

Carbon materials are important but find little application in bending components due to their unsatisfy-ing bending strength(300-500 MPa).To fabricate carbon composites of high bending strength is a tough task,even using carbon fibers(CFs)structures as reinforcements.Here we report lamellar carbon com-posites of ultra-high bending strength(>1.2 GPa)produced from CFs cloths coated with nano-diamond(ND)particles by spark plasma sintering(SPS).When NDs are sandwiched between CFs cloths,some ND particles penetrate into interstices between CFs.During the sintering,the ND particles are transformed into graphite onions;this transformation is associated with an active state of carbon atoms participating in the change.As a result,the carbon onions strongly bond the CFs together,helping consolidate the com-pacts into strong lamellar carbon composite bulks.The produced graphite onions from the NDs located at crossings of CFs tows form a robust mortise and tenon structure,which helps the bending strength of the lamellar composite from the compact of 40 wt.%NDs exceed 1.2 GPa.The as-prepared compos-ite possesses the highest specific bending strength of all current high temperature structural materials reported so far.This work may pave a new way for high performance carbon materials.

Inflammation as a Mediator of Microbiome Dysbiosis-Associated DNA Methylation Changes in Gastric Premalignant Lesions

Evidence for the influence of chronic inflammation induced by microbial dysbiosis on aberrant DNA methylation supports a plausible connexion between disordered microbiota and precancerous lesions of gastric cancer(PLGC).Here,a comprehensive study including multi-omics data was performed to estimate the relationships amongst the gastric microbiome,inflammatory proteins and DNA methylation alterations and their roles in PLGC development.The results demonstrated that gastric dysbacteriosis increased the risk of PLGC and DNA methylation alterations in related tumour suppressor genes.Seven inflammatory biomarkers were identified for antrum and corpus tissues,respectively,amongst which the expression levels of several biomarkers were significantly correlated with the microbial dysbiosis index(MDI)and methylation status of specific tumour suppressor genes.Notably,mediation analysis revealed that microbial dysbiosis partially contributed to DNA methylation changes in the stomach via the inflammatory cytokines C-C motif chemokine 20(CCL20)and tumour necrosis factor receptor superfamily member 9(TNFRSF9).Overall,these results may provide new insights into the mechanisms that might link the gastric microbiome to PLGC.

Sintering and mechanical properties of carbon bulks from ordered mesoporous carbon and nano diamond

Powder metallurgy is important in material preparation.Due to the inertness of carbon materials,however,sintering powdered carbon into physically coherent bulks has been a great challenge even at a high temperature(2000).Improving the sintering activity of carbon powders is℃the key to the success of the consolidation of the carbon powders.Here ordered mesoporous carbon(OMC)is used as the starting material to produce highly homogeneous novel carbon bulks.During sintering at 1800,the huge specific surface area of the OMC greatly promotes the migration of℃carbon atoms and thus the sintering of the OMC by surface diffusion mechanism.When nanodiamond(ND)is added,the volume expansion associated with the phase transformation of diamond to graphite facilitates the densification of the powder compacts.The strong connection between the OMC and the graphite onions derived from the ND bestows the as-prepared carbon bulks with excellent mechanical properties.The current research pioneers a novel way to prepare high-strength carbon materials at relatively low temperatures.