Showing papers by "YuanTong Gu published in 2020"

Metal-Nitrogen-Doped Carbon Materials as Highly Efficient Catalysts: Progress and Rational Design

Abstract: As a typical class of single-atom catalysts (SACs) possessing prominent advantages of high reactivity, high selectivity, high stability, and maximized atomic utilization, emerging metal-nitrogen-doped carbon (M-N-C) materials, wherein dispersive metal atoms are coordinated to nitrogen atoms doped in carbon nanomaterials, have presented a high promise to replace the conventional metal or metal oxides-based catalysts In this work, recent progress in M-N-C-based materials achieved in both theoretical and experimental investigations is summarized and general principles for novel catalysts design from electronic structure modulating are provided Firstly, the applications and mechanisms on the advantages and challenges of M-N-C-based materials for a variety of sustainable fuel generation and bioinspired reactions, including the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR), and nanozyme reactions are reviewed Then, strategies toward enhancing the catalytic performance by engineering the nature of metal ion centers, coordinative environment of active centers, carbon support, and their synergistic cooperation, are proposed Finally, prospects for the rational design of next generation high-performance M-N-C-based catalysts are outlined It is expected that this work will provide insights into high-performance catalysts innovation for sustainable and environmental technologies

A review of respiratory anatomical development, air flow characterization and particle deposition

Abstract: The understanding of complex inhalation and transport processes of pollutant particles through the human respiratory system is important for investigations into dosimetry and respiratory health effects in various settings, such as environmental or occupational health. The studies over the last few decades for micro- and nanoparticle transport and deposition have advanced the understanding of drug-aerosol impacts in the mouth-throat and the upper airways. However, most of the Lagrangian and Eulerian studies have utilized the non-realistic symmetric anatomical model for airflow and particle deposition predictions. Recent improvements to visualization techniques using high-resolution computed tomography (CT) data and the resultant development of three dimensional (3-D) anatomical models support the realistic representation of lung geometry. Yet, the selection of different modelling approaches to analyze the transitional flow behavior and the use of different inlet and outlet conditions provide a dissimilar prediction of particle deposition in the human lung. Moreover, incorporation of relevant physical and appropriate boundary conditions are important factors to consider for the more accurate prediction of transitional flow and particle transport in human lung. This review critically appraises currently available literature on airflow and particle transport mechanism in the lungs, as well as numerical simulations with the aim to explore processes involved. Numerical studies found that both the Euler–Lagrange (E-L) and Euler–Euler methods do not influence nanoparticle (particle diameter ≤50 nm) deposition patterns at a flow rate ≤25 L/min. Furthermore, numerical studies demonstrated that turbulence dispersion does not significantly affect nanoparticle deposition patterns. This critical review aims to develop the field and increase the state-of-the-art in human lung modelling.

High density mechanical energy storage with carbon nanothread bundle

Abstract: The excellent mechanical properties of carbon nanofibers bring promise for energy-related applications. Through in silico studies and continuum elasticity theory, here we show that the ultra-thin carbon nanothreads-based bundles exhibit a high mechanical energy storage density. Specifically, the gravimetric energy density is found to decrease with the number of filaments, with torsion and tension as the two dominant contributors. Due to the coupled stresses, the nanothread bundle experiences fracture before reaching the elastic limit of any individual deformation mode. Our results show that nanothread bundles have similar mechanical energy storage capacity compared to (10,10) carbon nanotube bundles, but possess their own advantages. For instance, the structure of the nanothread allows us to realize the full mechanical energy storage potential of its bundle structure through pure tension, with a gravimetric energy density of up to 1.76 MJ kg−1, which makes them appealing alternative building blocks for energy storage devices. Carbon nanothreads are promising for applications in mechanical energy storage and energy harvesting. Here the authors use large-scale molecular dynamics simulations and continuum elasticity theory to explore mechanical energy storage in carbon nanothreads-based bundles.

Thermal Transport in 3D Nanostructures

Abstract: This work summarizes the recent progress on the thermal transport properties of 3D nanostructures, with an emphasis on experimental results. Depending on the applications, different 3D nanostructures can be prepared or designed to either achieve a low thermal conductivity for thermal insulation or thermoelectric devices or a high thermal conductivity for thermal interface materials used in the continuing miniaturization of electronics. A broad range of 3D nanostructures are discussed, ranging from colloidal crystals/assemblies, array structures, holey structures, hierarchical structures, to 3D nanostructured fillers for metal matrix composites and polymer composites. Different factors that impact the thermal conductivity of these 3D structures are compared and analyzed. This work provides an overall understanding of the thermal transport properties of various 3D nanostructures, which will shed light on the thermal management at nanoscale.

Stacking-dependent interlayer magnetic coupling in 2D CrI3/CrGeTe3 nanostructures for spintronics

Abstract: The recent emergence of two-dimensional (2D) materials with intrinsic long-range magnetic order opens the avenue of fundamental physics studies and the spintronics application; however, the mechanism of interlayer magnetic coupling and the feasible way to control magnetic states are yet to be fully investigated. In the present study, from first-principle calculations, we studied the interlayer magnetic coupling of 2D CrI3/CrGeTe3 heterostructures and revealed the stacking-dependent magnetic states. It is found that AB and AB1 stacking are prefer ferromagnetic interlayer coupling, while the other two stacked configurations are in the ferrimagnetic state. The underlying mechanism has contributed to the competition between nearest-neighbor (NN) and second-nearest-neighbor (SNN) Cr-Cr atoms interaction between layers. Meanwhile, it is also found that the electronic properties are stacking dependent, while the band edge states are separated to the different layers. The magnetic and electronic states can be effectively tuned by the external strain. Based on these findings, the magnetic domain devices are proposed in the twisted magnetic heterostructures with the domain size and interlayer coupling being controlled by the rotation angle. Our study thus provides an approach to achieve the controllable magnetic/electronic properties which is not only important for fundamental research but also useful for the practical applications in spintronics.

Design tools for patient specific and highly controlled melt electrowritten scaffolds

Abstract: Melt electrowriting (MEW) has grown in popularity in biofabrication research due to its ability to fabricate complex, high-precision networks of fibres. These fibres can mimic the morphology of a natural extracellular matrix, enabling tissue analogues for transplantation or personalised drug screening. To date, MEW has employed two different collector-plate modalities for the fabrication of constructs. Flat collector plates, typical of traditional 3D printing methods, allow for the layer-by-layer fabrication of 2D structures into complex 3D structures. Alternatively, rotating mandrels can be used for the creation of tubular scaffolds. However, unlike other additive manufacturing techniques that can immediately start and stop the extrusion of material during printing, MEW instead requires a continuous flow of polymer. Consequently, conventional g-code control software packages are unsuitable. To overcome this challenge, a suite of customised pattern generation software tools have been developed to enable the design of MEW scaffolds with highly-controlled geometry, including crosshatch, gradient porosity, tubular, and patient-specific configurations. The high level of design control using this approach enables the production of scaffolds with highly adaptable mechanical properties, as well as the potential to influence biological properties for cell attachment and proliferation.

Reversible gas capture using a ferroelectric switch and 2D molecule multiferroics on the In2Se3 monolayer

Abstract: Two-dimensional ferroelectrics are important quantum materials which have found novel applications in nonvolatile memory devices, however the effects of their reversible polarization on chemical reactions and interactions with environments are rarely studied despite their importance. Here, based on first principles calculations, we found distinct gas adsorption behaviors on the surfaces of the ferroelectric In2Se3 layer and reversible gas capture and release controlled by a ferroelectric switch. We rationalize this novel phenomenon to the synergistic effect of electrostatic potential differences and electron transfer induced by band alignments between the frontier molecular orbitals of gas and the band-edge states of the substrate. Excitingly, the adsorption of paramagnetic gas molecules such as NO and NO2 can induce surface magnetism, which is also sensitive to the ferroelectric polarization direction of In2Se3, indicating the application of In2Se3 as a threshold magnetic sensor/switch. Furthermore, it is suggested that two NO molecules ferromagnetically couple with each other, leading to the Curie temperature being polarization surface dependent and it can reach up to 50 K, and long-sought 2D molecule multiferroics. The ferroelectric controllable adsorption behavior and multiferroic feature of the molecules will find extensive application in gas capture, selective catalytic reduction and spintronic devices.

Optical coherence tomography-based patient-specific coronary artery reconstruction and fluid–structure interaction simulation

Abstract: Plaque rupture is related to the mechanical stress it suffered. The value and distribution of the mechanical stress in plaque could help on assessing plaque vulnerability. To look into the stress conditions in the coronary artery, a patient-specific coronary model was created by using optical coherence tomography (OCT) and angiography imaging data. The reconstructed coronary model consisted of the structure of the lumen, the arterial wall and plaque components. Benefited by the high resolution of OCT, detailed structures such as the thin fibrous cap could be observed and built into the geometry. On this reconstructed coronary model, a fully coupled fluid–structure interaction (FSI) simulation was performed. The principle stress in coronary plaque and the wall shear stress (WSS) were analyzed. The FSI simulation results show that the cap thickness had a significant effect on the stress, and the principle stress at the thin cap area was more than double of those at the locations with a larger thickness. WSS is thought as an important parameter to assess the potentially dangerous areas of the atherosclerosis-prone (caused by low WSS) and the plaque rupture (high WSS). From the WSS plots of our FSI model, the area with abnormal WSS value was detected around the position where a lipid core existed. The FSI simulation results were compared with the results from the conventional structure-only and the computational fluid dynamics (CFD)-only computational models to quantify the difference between the three models. We found little difference in the principle stress results between the FSI and the structure-only model, but a significant difference between the FSI and the CFD-only model when looking into the WSS. The WSS values at the two observation spots from the CFD-only model were higher than the values from the FSI model by 17.95% and 22.66% in average, respectively. Furthermore, the FSI model detected more areas of low WSS, because the fluid domain could expand circumferentially when pressure loaded on the flexible arterial. This study suggests that OCT-based FSI model may be useful for plaque vulnerability assessment and it may be critical to perform the FSI simulation if an accurate WSS value is required.

Tuning Magnetism of Metal Porphyrazine Molecules by a Ferroelectric In2Se3 Monolayer.

Abstract: Electric field tuning of magnetism is highly desirable for nanoelectronics, but volatility in electron spin manipulation presents a major challenge that needs urgent resolution. Here, we show by first-principles calculations that magnetism of metal porphyrazine (MPz) molecules can be effectively tuned by switching ferroelectric polarization of an adjacent In2Se3 monolayer. The magnetic moments of TiPz and VPz (MnPz, FePz, and CoPz) decrease (increase) at one polarization but remain unchanged at reversed polarization. This intriguing phenomenon stems from distinct metal d-orbital occupation caused by electron transfer and energy-level shift associated with the polarization switch of the In2Se3 monolayer. Moreover, the ferroelectric switch also tunes the underlying electronic properties, producing a metallic, half-metallic, or semiconducting state depending on polarization. These findings of robust ferroelectric tuning of magnetism and related electronic properties in MPz-adsorbed In2Se3 hold great promise for innovative design and implementation in advanced magnetic memory storage, sensor, and spintronic devices.

Multiferroic decorated Fe2O3 monolayer predicted from first principles

Abstract: Two-dimensional (2D) multiferroics exhibit cross-control capacity between magnetic and electric responses in a reduced spatial domain, making them well suited for next-generation nanoscale devices; however, progress has been slow in developing materials with required characteristic properties Here we identify by first-principles calculations robust 2D multiferroic behaviors in decorated Fe2O3 monolayers, showcasing Li@Fe2O3 as a prototypical case, where ferroelectricity and ferromagnetism stem from the same origin, namely Fe d-orbital splitting induced by the Jahn-Teller distortion and associated crystal field changes These findings establish strong material phenomena and elucidate the underlying physics mechanism in a family of truly 2D multiferroics that are highly promising for advanced device applications

Characterisation on the hygrothermal degradation in the mechanical property of structural adhesive: A novel meso-scale approach

Abstract: Structural adhesives are being increasingly used for bonding of dissimilar materials, however environmental degradation remains a significant challenge limiting the bonding reliability. A common form of degradation comes from water ingress, regarding which there is limited quantitative understanding of how water diffusion affects the adhesive local mechanical properties. This work proposes a meso-scale approach to characterise the influence of water diffusion on local mechanical properties of structural adhesives at elevated temperature, aiming to develop a model of degradation due to water exposure. Gravimetric study was conducted on adhesives immersed in deionised and 5 wt% NaCl water, to obtain water diffusion characteristics. The immersed specimens were periodically removed from the aqueous environment and precisely cut to expose the internal section. The samples were then indented using nanoindentation to extract the modulus and hardness distribution. SEM observation was conducted to analyse the microscopic morphology and ageing mechanism. Experimental results revealed that water diffusion caused significant local (meso-scale) degradation in adhesive mechanical properties. Increase in local moisture concentration led to greater degradation as moisture gradually diffused inward. Comparing to salt water immersion, the elastic modulus and hardness of adhesive saturated in deionised water decreased by further 5.9% and 11.9%, respectively. The developed degradation model coupled with insights from ageing mechanism provides a detailed understanding of degradation in adhesive property due to water diffusion. The proposed characterisation approach can be readily applied to other adhesives. Furthermore, this model allows for degradation of such adhesives to be reasonably predicted through FE modelling effort.

Development of Mechanically Enhanced Polycaprolactone Composites by a Functionalized Titanate Nanofiller for Melt Electrowriting in 3D Printing.

Abstract: Three-dimensional (3D) printing technologies are widely applied in various industries and research fields and are currently the subject of intensive investigation and development. However, high-performance materials that are suitable for 3D printing are still in short supply, which is a major limitation for 3D printing, particularly for biomedical applications. The physicochemical properties of single constituent materials may not be sufficient to meet the needs of modern biotechnology development and production. To enhance the materials' performance and broaden their applications, this work designed and tested a series of titanate nanofiller (nanowire and nanotube)-enhanced polycaprolactone (PCL) composites that were 3D-printable and provided superior mechanical properties. By grafting two different functional groups (phenyl- and thiol-terminated ligands), the nanofiller surface showed improved hydrophobicity, which significantly improved their dispersion in the PCL matrix. After characterizing the surface modification, we evaluated the significance of the homogeneity of the ceramic nanofiller in terms of printability, formability, and mechanical strength. Melt electrowriting additive manufacturing was used to fabricate microfibers of PCL and PCL/nanofiller composites. Improved nanofiller dispersion enabled intact and uniform sample morphology, and in contrast, nanofiller aggregation greatly varied the viscosity during the printing process, which could result in poorly printed structures. Importantly, the modified ceramic/PCL composite delivered enhanced and stable mechanical properties, where its Young's modulus was measured to be 1.67 GPa, which is more than 7 times higher compared to that of pristine PCL (0.22 GPa). Retaining the cell safety properties (comparable to PCL), the concept of enhancing biocompatible polymers with modified nanofillers shows great potential in the field of customized 3D printing for biomedicine.

Helium–oxygen mixture model for particle transport in CT-based upper airways

Abstract: The knowledge of respiratory particle transport in the extra-thoracic pathways is essential for the estimation of lung health-risk and optimization of targeted drug delivery. The published literature reports that a significant fraction of the inhaled aerosol particles are deposited in the upper airways, and available inhalers can deliver only a small amount of drug particles to the deeper airways. To improve the targeted drug delivery efficiency to the lungs, it is important to reduce the drug particle deposition in the upper airways. This study aims to minimize the unwanted aerosol particle deposition in the upper airways by employing a gas mixture model for the aerosol particle transport within the upper airways. A helium–oxygen (heliox) mixture (80% helium and 20% oxygen) model is developed for the airflow and particle transport as the heliox mixture is less dense than air. The mouth–throat and upper airway geometry are extracted from CT-scan images. Finite volume based ANSYS Fluent (19.2) solver is used to simulate the airflow and particle transport in the upper airways. Tecplot software and MATLAB code are employed for the airflow and particle post-processing. The simulation results show that turbulence intensity for heliox breathing is lower than in the case of air-breathing. The less turbulent heliox breathing eventually reduces the deposition efficiency (DE) at the upper airways than the air-breathing. The present study, along with additional patient-specific investigation, could improve the understanding of particle transport in upper airways, which may also increase the efficiency of aerosol drug delivery.

Molecular Dynamics Simulation of Chiral Carbon Nanothread Bundles for Nanofiber Applications

Abstract: Carbon nanofibers as constructed from various one-dimensional carbon nanostructure, such as sp3 diamond nanowire, sp2 carbon nanotubes, and carbyne, have received enormous interest from both scientific and engineering communities. The newly synthesized nanostructure carbon nanothreads (C_NTH) show superior properties and make them ideal building blocks for high-performance carbon nanofibers. This work systematically investigates the torsional properties of C_NTH bundles through high-throughput large-scale molecular dynamics simulations. Our results show that the torsional behavior of C_NTH bundles depends strongly on the loading direction. By adjusting the enantiomer ratios, we can effectively tune the mechanical properties of the bundle structure, including the strain energy density, elastic limit, and torsional rigidity. Benefiting from their rich structural varieties, this work suggests that carbon nanothreads are promising candidates for the next-generation high-performance carbon nanofiber.

Effect of hydroxylysine-O-glycosylation on the structure of type I collagen molecule: A computational study.

Abstract: Collagen undergoes many types of post-translational modifications (PTMs), including intracellular modifications and extracellular modifications. Among these PTMs, glycosylation of hydroxylysine (Hyl) is the most complicated. Experimental studies demonstrated that this PTM ceases once the collagen triple helix is formed and that Hyl-O-glycosylation modulates collagen fibrillogenesis. However, the underlying atomic-level mechanisms of these phenomena remain unclear. In this study, we first adapted the force field parameters for O-linkages between Hyl and carbohydrates and then investigated the influence of Hyl-O-glycosylation on the structure of type I collagen molecule, by performing comprehensive molecular dynamic simulations in explicit solvent of collagen molecule segment with and without the glycosylation of Hyl. Data analysis demonstrated that (i) collagen triple helices remain in a triple-helical structure upon glycosylation of Hyl; (ii) glycosylation of Hyl modulates the peptide backbone conformation and their solvation environment in the vicinity and (iii) the attached sugars are arranged such that their hydrophilic faces are well exposed to the solvent, while their hydrophobic faces point towards the hydrophobic portions of collagen. The adapted force field parameters for O-linkages between Hyl and carbohydrates will aid future computational studies on proteins with Hyl-O-glycosylation. In addition, this work, for the first time, presents the detailed effect of Hyl-O-glycosylation on the structure of human type I collagen at the atomic level, which may provide insights into the design and manufacture of collagenous biomaterials and the development of biomedical therapies for collagen-related diseases.

Modelling of red blood cell morphological and deformability changes during in-vitro storage

Abstract: Storage lesion is a critical issue facing transfusion treatments, and it adversely affects the quality and viability of stored red blood cells (RBCs). RBC deformability is a key indicator of cell health. Deformability measurements of each RBC unit are a key challenge in transfusion medicine research and clinical haematology. In this paper, a numerical study, inspired from the previous research for RBC deformability and morphology predictions, is conducted for the first time, to investigate the deformability and morphology characteristics of RBCs undergoing storage lesion. This study investigates the evolution of the cell shape factor, elongation index and membrane spicule details, where applicable, of discocyte, echinocyte I, echinocyte II, echinocyte III and sphero-echinocyte morphologies during 42 days of in-vitro storage at 4 °C in saline-adenine-glucose-mannitol (SAGM). Computer simulations were performed to investigate the influence of storage lesion-induced membrane structural defects on cell deformability and its recoverability during optical tweezers stretching deformations. The predicted morphology and deformability indicate decreasing quality and viability of stored RBCs undergoing storage lesion. The loss of membrane structural integrity due to the storage lesion further degrades the cell deformability and recoverability during mechanical deformations. This numerical approach provides a potential framework to study the RBC deformation characteristics under varying pathophysiological conditions for better diagnostics and treatments.

Stress-Relaxation and Cyclic Behavior of Human Carotid Plaque Tissue.

Abstract: Atherosclerotic plaque rupture is a catastrophic event that contributes to mortality and long-term disability. A better understanding of the plaque mechanical behavior is essential for the identification of vulnerable plaques pre-rupture. Plaque is subjected to a natural dynamic mechanical environment under hemodynamic loading. Therefore, it is important to understand the mechanical response of plaque tissue under cyclic loading conditions. Moreover, experimental data of such mechanical properties are fundamental for more clinically relevant biomechanical modeling and numerical simulations for risk stratification. This study aims to experimentally and numerically characterize the stress-relaxation and cyclic mechanical behavior of carotid plaque tissue. Instron microtester equipped with a custom-developed setup was used for the experiments. Carotid plaque samples excised at endarterectomy were subjected to uniaxial tensile, stress-relaxation, and cyclic loading protocols. Thirty percent of the underlying load level obtained from the uniaxial tensile test results was used to determine the change in mechanical properties of the tissue over time under a controlled testing environment (Control tests). The stress-relaxation test data was used to calibrate the hyperelastic (neo-Hookean, Ogden, Yeoh) and linear viscoelastic (Prony series) material parameters. The normalized relaxation force increased initially and slowly stabilized toward the end of relaxation phase, highlighting the viscoelastic behavior. During the cyclic tests, there was a decrease in the peak force as a function of the cycle number indicating mechanical distension due to repeated loading that varied with different frequencies. The material also accumulated residual deformation, which increased with the cycle number. This trend showed softening behavior of the samples. The results of this preliminary study provide an enhanced understanding of in vivo stress-relaxation and cyclic behavior of the human atherosclerotic plaque tissue.

Robust Magnetoelectric Effect in Decorated Graphene/In2Se3 Heterostructure

Abstract: Magnetoelectric effect is a fundamental physics phenomenon that synergizes electric and magnetic degrees of freedom to generate distinct material responses like electrically tuned magnetism, which serves as a key foundation of the emerging field of spintronics. Here, we show by first-principles studies that ferroelectric (FE) polarization of an In2Se3 monolayer can modulate the magnetism of an adjacent transition-metal (TM) decorated graphene layer via an FE induced electronic transition. The TM nonbonding d-orbital shifts downward and hybridizes with carbon p states near the Fermi level, suppressing the magnetic moment, under one FE polarization, but on reversed FE polarization this TM d-orbital moves upward, restoring the original magnetic moment. This finding of robust magnetoelectric effect in TM decorated graphene/In2Se3 heterostructure offers powerful insights and a promising avenue for experimental exploration of FE controlled magnetism in 2D materials.

Deformation behaviour of stomatocyte, discocyte and echinocyte red blood cell morphologies during optical tweezers stretching.

Abstract: The red blood cell (RBC) deformability is a critical aspect, and assessing the cell deformation characteristics is essential for better diagnostics of healthy and deteriorating RBCs. There is a need to explore the connection between the cell deformation characteristics, cell morphology, disease states, storage lesion and cell shape-transformation conditions for better diagnostics and treatments. A numerical approach inspired from the previous research for RBC morphology predictions and for analysis of RBC deformations is proposed for the first time, to investigate the deformation characteristics of different RBC morphologies. The present study investigates the deformability characteristics of stomatocyte, discocyte and echinocyte morphologies during optical tweezers stretching and provides the opportunity to study the combined contribution of cytoskeletal spectrin network and the lipid-bilayer during RBC deformation. The proposed numerical approach predicts agreeable deformation characteristics of the healthy discocyte with the analogous experimental observations and is extended to further investigate the deformation characteristics of stomatocyte and echinocyte morphologies. In particular, the computer simulations are performed to investigate the influence of direct stretching forces on different equilibrium cell morphologies on cell spectrin link extensions and cell elongation index, along with a parametric analysis on membrane shear modulus, spectrin link extensibility, bending modulus and RBC membrane–bead contact diameter. The results agree with the experimentally observed stiffer nature of stomatocyte and echinocyte with respect to a healthy discocyte at experimentally determined membrane characteristics and suggest the preservation of relevant morphological characteristics, changes in spectrin link densities and the primary contribution of cytoskeletal spectrin network on deformation behaviour of stomatocyte, discocyte and echinocyte morphologies during optical tweezers stretching deformation. The numerical approach presented here forms the foundation for investigations into deformation characteristics and recoverability of RBCs undergoing storage lesion.

Carbon Nanotube Reinforced Poly-p-Phenylene Terephthalamide Fibers for Toughness Improvement: A Molecular Dynamics Study

Abstract: Poly-p-phenylene terephthalamide (PPTA) fibers, such as DuPont's Kevlar fiber, are widely used in various fiber-reinforced composites due to their outstanding tensile stiffness, strength, and energy absorption capacity. To further improve the strength of PPTA-based fibers, it is necessary to investigate the molecular deformation mechanisms of these fibers while being coupled with nanoreinforcements. In this work, molecular dynamics method is used to predict the mechanical performance of carbon nanotubes (CNTs) reinforced Kevlar fibers, based on the molecular modeling of crystal interfaces in the microstructure of Kevlar fiber with the help of surface-modified CNTs, the tensile strength of Kevlar fibers can be increased by 27.8–39.7%. Furthermore, the mechanism of binding stability of CNTs is investigated by modifying the functional groups of CNTs, in which the hydrogen bonds (H-bonds) interaction plays an important role.

Atomistic Mechanisms of Ultralarge Bending Deformation of Single-Crystalline TiO2-B Nanowires

Abstract: Titanium dioxide (TiO2) nanowires (NWs) are usually considered to be brittle semiconductor materials, which limits their use in strain-related applications, even though they are already widely appl...

Tumor-Targeting Fluorescent Probe Based on 1,8-Naphthalimide and Porphyrin Groups

Abstract: Targeted tumor imaging in vivo has been one of the main challenges in the early stage of cancer diagnosis and therapy. However, few contrast probes are available to specifically respond to tumor environments. The aim was to investigate porphyrin-1,8-naphthalimide derivative (APTSPP-2NI) as a potential tumor-targeting fluorescent probe in vitro and in vivo. A tumor-targeting APTSPP-2NI was synthesized by the incorporation of water-soluble 5-(4’-aminophenyl)-10,15,20-tris(4’-sulfonato-phenyl) porphyrin (APTSPP) as a tumor-targeting group into N-butyl-4-ethyldiamino-1,8-naphthalene imide (NI) fluorescence molecule herein. The derivative was further characterized and its properties in vitro and in vivo including the cell cytotoxicity, cell uptake of tumor cells and fluorescent imaging were also evaluated. Experiment results indicated that APTSPP-2NI possessed the low cell cytotoxicity and good tumor-targeting property to the B16F10 melanoma cells. Moreover, APTSPP-2NI can be taken up highly by B16F10 melanoma tumors and then achieve the good green and red fluorescent imaging in B16F10 melanoma tumors. Therefore APTSPP-2NI can be considered as a potential tumor-targeting dual-mode enhanced probe in fluorescent imaging in vitro and in vivo.