Ultrathin and Flexible CNTs/MXene/Cellulose Nanofibrils Composite Paper for Electromagnetic Interference Shielding

As the rapid development of portable and wearable devices,different electromagnetic interference(EMI)shielding materials with high efficiency have been desired to eliminate the resulting radiation pollution.However,limited EMI shielding materials are successfully used in practical applications,due to the heavy thickness and absence of sufficient strength or flexibility.Herein,an ultrathin and flexible carbon nanotubes/MXene/cellulose nanofibrils composite paper with gradient and sandwich structure is constructed for EMI shielding application via a facile alternating vacuum-assisted filtration process.The composite paper exhibits outstanding mechanical properties with a tensile strength of 97.9±5.0 MPa and a fracture strain of 4.6±0.2%.Particularly,the paper shows a high electrical conductivity of 2506.6 S m?1 and EMI shielding effectiveness(EMI SE)of 38.4 dB due to the sandwich structure in improving EMI SE,and the gradient structure on regulating the contributions from reflection and absorption.This strategy is of great significance in fabricating ultrathin and flexible composite paper for highly efficient EMI shielding performance and in broadening the practical applications of MXene-based composite materials.

Research on Acidic Stability of Immobilized Heavy Metals in Sediment from Polluted River

The heavy metals can accumulate in sediment after discharged into surface water bodies. Before the sediment can be further landfilled or recycled,a large amount of heavy metal in it needs to be treated,known as solidification/stabilization. The properties of treated sediment may change with environment such as acid rain and landfill time,which may lead to the release of heavy metals from treated sediment into environment,posing great risks to environment and human health. In this study,the quantitative relationship has been tested between the dissolution of heavy metals from treated sediment and the p H of the leaching solution,by changing the p H of the treated sediment-leaching solution continuously. The results showed that when the p H of the treated sediment-leaching solution was higher than 5. 5,the heavy metals released from the treated sediment into solution were relatively low;when the p H of the treated sediment-leaching solution dropped to about 5. 5,a large amount of Cu,Zn,Ni and other heavy metals were released. The solidification of Cu,Zn,Cr and Cd in the treated sediment is relatively stable,while that of Ni and Pb still need to be improved. The buffer capacity of the treated sediment to acid is 0. 999 meq/g,which means it has relatively high capacity to buffer the pH change caused by external acid.

Association of TRMT2B gene variants with juvenile amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis(ALS)is a fatal neurodegenerative disease characterized by progressive degeneration of motor neurons,and it demonstrates high clinical heterogeneity and complex genetic architecture.A variation within TRMT2B(c.1356G>T;p.K452N)was identified to be associated with ALS in a family comprising two patients with juvenile ALS(JALS).Two missense variations and one splicing variation were identified in 10 patients with ALS in a cohort with 910 patients with ALS,and three more variants were identified in a public ALS database including 3317 patients with ALS.A decreased number of mitochondria,swollen mitochondria,lower expression of ND1,decreased mitochondrial complex I activities,lower mitochondrial aerobic respiration,and a high level of ROS were observed functionally in patient-originated lymphoblastoid cell lines and TRMT2B interfering HEK293 cells.Further,TRMT2B variations overexpression cells also displayed decreased ND1.In conclusion,a novel JALS-associated gene called TRMT2B was identified,thus broadening the clinical and genetic spectrum of ALS.

Glycerol solutions of highly concentrated biomineral counter-ions towards water-responsive mineralization: Demonstration on bacterial cellulose and its application in hard tissue repair

Mineralization has found widespread use in the fabrication of composite biomaterials for hard tissue regeneration.The current mineralization processes are mainly carried out in neutral aqueous solutions of biomineral counter-ions(a pair of cation and anion that form the corresponding minerals at certain conditions),which are stable only at very low concentrations.This typically results in inefficient mineralization and weak control over biomineral formation.Here,we find that,in the organic solvent glycerol,a variety of biomineral counter-ions(e.g.,Ca/PO_(4),Ca/CO_(3),Ca/SO_(4),Mg/PO_(4),or Fe/OH)corresponding to distinct biominerals at significantly high concentrations(up to hundreds-fold greater than those of simulated body fluid(SBF))are able to form translucent and stable solutions(mineralizing solution of highly concentrated counter-ions(MSCIs)),and mineralization can be triggered upon them with external solvents(e.g.,water or ethanol).Furthermore,with pristine bacterial cellulose(BC)membrane as a model,we demonstrate an effective and controllable mineralization performance of MSCIs on organic substrates.This approach not only forms the homogeneous biominerals on the BC fibers and in the interspaces,but also provides regulations over mineralization rate,mineral content,phase,and dopants.The resulting mineralized BC membranes(MBCs)exhibit high cytocompatibility and favor the proliferation of rat bone marrow mesenchymal stem cells(rBMSC).Following this,we prepare a mineralized bone suture(MBS)from MBC for non-weight bearing bone fixation,which then is tested on a rabbit median sternotomy model.It shows firm fixation of the rabbit sternum without causing discernible toxicity or inflammatory response.This study,by extending the mineralization to the organic solution system of highly concentrated counter-ions,develops a promising strategy to design and build targeted mineral-based composites.

A feature-wise attention module based on the difference with surrounding features for convolutional neural networks

Attention mechanism has become a widely researched method to improve the performance of convolutional neural networks(CNNs).Most of the researches focus on designing channel-wise and spatial-wise attention modules but neglect the importance of unique information on each feature,which is critical for deciding both“what”and“where”to focus.In this paper,a feature-wise attention module is proposed,which can give each feature of the input feature map an attention weight.Specifically,the module is based on the well-known surround suppression in the discipline of neuroscience,and it consists of two sub-modules,Minus-Square-Add(MSA)operation and a group of learnable non-linear mapping functions.The MSA imitates the surround suppression and defines an energy function which can be applied to each feature to measure its importance.The group of non-linear functions refines the energy calculated by the MSA to more reasonable values.By these two sub-modules,feature-wise attention can be well captured.Meanwhile,due to the simple structure and few parameters of the two sub-modules,the proposed module can easily be almost integrated into any CNN.To verify the performance and effectiveness of the proposed module,several experiments were conducted on the Cifar10,Cifar100,Cinic10,and Tiny-ImageNet datasets,respectively.The experimental results demonstrate that the proposed module is flexible and effective for CNNs to improve their performance.

Amorphous calcium magnesium phosphate nanocomposites with superior osteogenic activity for bone regeneration

The seek of bioactive materials for promoting bone regeneration is a challenging and longterm task.Functionalization with inorganic metal ions or drug molecules is considered effective strategies to improve the bioactivity of various existing biomaterials.Herein,amorphous calcium magnesium phosphate(ACMP)nanoparticles and simvastatin(SIM)-loaded ACMP(ACMP/SIM)nanocomposites were developed via a simple co-precipitation strategy.The physiochemical property of ACMP/SIM was explored using transmission electron microscope(TEM),Fourier transform infrared spectroscopy(FTIR),powder X-ray diffraction(XRD)and highperformance liquid chromatograph(HPLC),and the role of Mg^(2+) in the formation of ACMP/SIM was revealed using X-ray absorption near-edge structure(XANES).After that,the transformation process of ACMP/SIM in simulated body fluid(SBF)was also tracked to simulate and explore the in vivo mineralization performance of materials.We find that ACMP/SIM releases ions of Ca^(2+),Mg^(2+)and PO_(4)^(3),when it is immersed in SBF at 37℃,and a phase transformation occurred during which the initially amorphous ACMP turns into self-assembled hydroxyapatite(HAP).Furthermore,ACMP/SIM displays high cytocompatibility and promotes the proliferation and osteogenic differentiation of MC3T3-E1 cells.For the in vivo studies,lamellar ACMP/SIM/Collagen scaffolds with aligned pore structures were prepared and used to repair a rat defect model in calvaria.ACMP/SIM/Collagen scaffolds show a positive effect in promoting the regeneration of calvaria defect after 12weeks.The bioactive ACMP/SIM nanocomposites are promising as bone repair materials.Considering the facile preparation process and superior in vitro/vivo bioactivity,the as-prepared ACMP/SIM would be a potential candidate for bone related biomedical applications.