Computational studies were performedto understand the interfacial behaviour of MoS2 and graphene, whichproves high stability of the composite with high interfacial binding energy(−2.02 eV) among them. Further, the lithium and sodiumstorage properties have been tested and reveal excellent cyclic stability over 250and 500 cycles, respectively, with the highest initial capacity values of1300 mAh g−1 and 640 mAhg−1 at 0.1 Ag−1.Developing nano/micro-structures which can effectively upgrade the intriguingproperties of electrode materials for energy storage devices is always a keyresearch topic. Ultrathin nanosheets were proved to be one of the potentialnanostructures due to their high specific surface area, good active contact areasand porous channels. Herein, we report a unique hierarchical micro-sphericalmorphology of well-stacked and completely miscible molybdenum disulfide(MoS In recent years, room temperature sodium-ion batteries (SIBs) have been the object ofsignificant interest for their potential application in large-scale energy storagesystems. This is mainly caused by concerns about insufficient lithium ores to satisfythe increasing demands for lithium-ion batteries (LIBs), as well as because sodium is arelatively cheaper option compared to lithium, which could be significant in large-scaleapplications such as grid storage. In addition, the electrochemical principles of SIBsare identical to those of LIBs2+ between the MoS2 layers456782 has been greatly improved , large volume changesoccur during charge-discharge cycling, which results in poor cycling stability. Severalmethods have been reported to successfully improve the cycling stability, such asexfoliation and restacking of MoS2 layers2 layers,1113215161718192021+ per MoS2. Considering the advantages of graphene as ahighly conductive and stable material, Wang et al.2—graphene nanocomposite with an improved electrochemicalperformance when compared to pristine MoS2, however, there is no clearevidence of well-ordered stacking of the MoS2 and graphene nanosheets amongthemselves. Three-dimensional (3D) hierarchical micro-spherical architectures withnanostructures as building blocks are considered to be electrochemically andstructurally stable morphology that could lead to improved practical application of suchactive materials in battery systemsAmongst various anode materials, molybdenum disulfide is one of the earliest compoundsstudied for rechargeable LIBs due to its layered structure, which can intercalateLi2-graphene composites with a unique micro-spherical morphologysynthesized via the spray-drying technique, which is an industrial-scale synthesisprocedure for a large-scale production of composite powders with a controllable narrowparticle size distribution and nano/micro-spherical morphology2 and graphene nanosheets could be an efficient structure to enhancethe interfacial effect between graphene-like MoS2 and graphene, thus takingfull advantages from both MoS2 and graphene components and achieving highcapacity, excellent cycle life and high rate capability as electrode materials for LIBsand SIBs.In this work, we are reporting structurally and electrochemically optimizedMoS2and graphene oxide, two proportions of MoS2: graphene oxide i.e., 80:20and 60:40 were optimized based on structural and electrochemical aspects. Thesynthesis of the MoS2-graphene composites with two different grapheneratios is briefly described in 2 andgraphene oxide were mixed in 80:20 (MoS2-G1) and 60:40(MoS2-G2) ratios to form a homogenous mixture. The graphene oxide sheetsand MoS2 sheets were well dispersed among each other and no aggregationwere observed after leaving the solution undisturbed overnight. The solutions forthe samples were then pumped through a nozzle using a peristaltic pump into acustom-made spray-drying reactor at 350 °C. The resultantblack fluffy powders were collected using a cyclone collector attached to the spraydrying reactor. The products were then annealed at 800 °C inH2/Ar gas flow for 2 h to fully reduce the grapheneoxide. The samples were then characterized using X-ray diffraction (XRD) todetermine the phase of the material as shown in 2, MoS2-G1, and MoS2-G2,show peaks which can be indexed to hexagonal MoS2 (ICDD# 37-1492) and noimpurity peaks can be observed. In order to determine the amount of graphene presentin the samples after annealing, thermo-gravimetric analysis (TGA) was performed onthe samples. The samples were loaded into alumina crucibles and heated in flowingair at the rate of 5 °C/min up to700 °C. Based on the assumption that all the MoS2is converted into MoO3 at 700 °C, the carboncontent estimated for MoS2-G1 and MoS2-G2 is13 wt% and 26 wt%, respectively, as shown in 2 sample can be attributed to adsorbed CO2 on thesurface of the samples. The ratio of C to O is roughly 1:2. The atomic percentages(%) of C in MoS2-G1 and MoS2-G2 agree well with the resultsfrom TGA, where the later has a higher amount of graphene sheets present. For allthree samples, the ratio of Mo to S is roughly 1:2, which suggest there is minimalor no oxidation of MoS2. This is further confirmed by Raman spectroscopy,as shown in −1 can be attributed tohexagonal phase MoS2, which is in well agreement with the literatureelsewhere−1 and1597 cm−1, respectively, can be observedon the spectra of MoS2-G1 and MoS2-G2.After preparation of composite material with various proportions of MoS2, MoS2-G1 and MoS2-G2samples was investigated using field emission scanning electron microscopy (FESEM),and the images are shown in 2-G2 are shown in 2 nanosheets. In addition, the spherical morphology ofthe sample enables the sheets to naturally stack on top of each other rather than ina random stacking. When the SAED pattern was collected from a larger area coveringthe sides of the sphere, rings were observed instead of the bright dots. Both of theSAED patterns can be indexed to the hexagonal MoS2 phase consistent withthe XRD results. High resolution TEM (HRTEM) was also used to study the distributionof the MoS2 and graphene nanosheets. 2nanosheets are stacked on top of each other, forming a sandwich-like structure. Sucha unique spherical microstructure with inter-stacked graphene and MoS2nanosheets is due to a combination of several factors. The miscibility and stabilityof the graphene oxide and the MoS2 nanosheets in aqueous solution is veryimportant to provide the sandwich-like stacking, while the spray-drying process iscrucial in providing the spherical morphology of the end product. The thickness ofthe stacks of graphene and MoS2 nanosheets was determined to be from3–15 layers by studying 10 random areas using HRTEM. d-spacing of the MoS2 and graphene nanosheets, whichwere measured to be 0.63 nm and 0.34 nm, respectively. TEManalysis of MoS2 and MoS2-G1 was also carried out, yieldingsimilar results. The images and diffraction patterns are presented in 2, MoS2-G1 and MoS2-G2 samples andrepresented in The morphology of the MoS2 and graphene. A (5 × 5)single graphene layer containing 50 carbon atoms was used to match a(4 × 4) MoS2 monolayer containing 16Mo and 32 S atoms. The lattice mismatch between the graphene and the MoS2monolayer is only 1.3%. Plane-wave basis VASP code was used to perform all thecalculations26302 geometry. The equilibriumdistance between the graphene layer and the top of the MoS2 monolayer iscalculated to be 3.34 Ǻ. The interface adhesion energy,Ead, was obtained according to the followingequation,Computational studies were performed to further understand the interfacial behaviourof MoSEcomb, Egraphene, andEMoS2 represent the total energy of the relaxed hybridgraphene-MoS2 complex, the pure graphene sheet, and the MoS2monolayer, respectively. The interface binding energy is as high as−2.02 eV for the whole model interface, which indicates veryhigh stability. To characterize the electron coupling at thegraphene-MoS2 interface, three-dimensional (3D) charge densitydifference plots were calculated by subtracting the electronic charge of the hybridgraphene-MoS2 nanocomposite from those of the separate graphene layerand the MoS2 monolayer, as shown in 2 surface in the ground electronic state.Where −1 over 50 cycles. In the firstdischarge, MoS2-G2 shows the highest capacity at 1300 mAhg−1, while MoS2-G1 and MoS2show 800 mAh g−1 and 630 mAhg−1, respectively. Large irreversible capacity isobserved for all three samples, as the first charge capacities are 945, 660, and480 mAh g−1 for MoS2-G2,MoS2-G1, and MoS2, respectively as shown in −1 for MoS2-G2, MoS2-G1, andMoS2, respectively, at the end of cycling. The samples were furthertested for their rate performances up to the current density of 5 Ag−1. The MoS2-G2 sample showed the bestrate performance, retaining 590 mAh g−1 at5 A g−1. The MoS2-G1 andMoS2 managed to retain 435 and 387 mAhg−1, respectively, at 5 Ag−1. When the rate was recovered to 0.5 Ag−1, all the samples showed capacity recovery, whereMoS2-G2, MoS2-G1, and MoS2, recovered 820, 680,and 560 mAh g−1, respectively. It should benoted that the rate performances improved with increasing graphene content in thesamples. This can be justified by the increased conductivity provided by thegraphene nanosheets in the samples. In order to investigate the long-term cyclingstability, the samples were tested at 50 mAg−1 for the initial 5 cycles, then at 1 Ag−1 up to 250 cycles. The MoS2 samplesrecorded a stable capacity of 500 mAh g−1 upto the 75th cycle, and then the capacity gradually faded over 50cycles. The capacity after the 125th cycle is negligible. This couldbe attributed to huge volume expansions of pristine MoS2 duringcharge-discharge process and gradually results in pulverization of electrodes overcycle life. The spherical shape of the MoS2 sample yielded improvedcycling stability and rate performances when compared to the bulk MoS2,which has been reported by us previously2-G2, and MoS2-G1 samples exhibit stable cycling over 250cycles, retaining 780 and 700 mAh g−1,respectively. From the cycling tests in lithium half-cells, it can be noted thatgraphene nanosheets in the samples are crucial for improving both the capacity andthe cycling performance.The samples were studied for their lithium storage properties and the results areplotted in xMoS2, remaining Na1-xions reacting with MoS2 and reduction of Mo4+ to metallicMo along with formation of Na2S particulates, respectively. Theseobservations are in consistent with the reports elsewhere1617−1, all three samples showstable cycling behavior over 50 cycles. The initial discharge and charge capacitiesare 640 and 400, 620 and 420, and 430 and 280 mAhg−1, for MoS2-G2, MoS2-G1, andMoS2, respectively. The irreversible capacities of about 35% .These excellent electrochemical properties in both LIBs and SIBs could be attributedto various reasons such as: (i) the well-ordered stacking and excellent miscibilityof the MoS2 layers and graphene sheets, which leads to improvedconductivity, and thereby, improved cycling performance and rate capability; (ii)suppression of volume changes by the structurally stable nanosheets in microspheresduring cycling; and (iii) good penetration of electrolyte into and among theMoS2 and graphene nanosheets. In addition, these microspheres withhierarchical nanostructures benefit from both micro-materials (high tap density) andnanomaterials (short Li/Na diffusion pathways), leading to densely packed electrodesand improved battery life in practical applications333435Furthermore, the samples were studied for their sodium storage properties inroom-temperature sodium half-cells using similar testing conditions to those forlithium cells see . In the  35% see can be dth cycle 0 mAh g−12)-graphene composite with uniquehierarchical microsphere morphology was prepared by the spray-drying technique. Thecomposite microspheres consist of well-ordered stacks with MoS2 andgraphene nanosheets with a high interfacial binding energy(−2.02 eV). Under testing for their lithium and sodiumstorage properties, MoS2-graphene (26 wt.%) microspherespresented excellent cycling stability and rate capability, with initial dischargecapacities of 1300 mAh g−1 and640 mAh g−1 at 0.1 Ag−1 in LIBs and SIBs, respectively. Notably, in SIBsat 1 A g−1, MoS2-G2 showed 93%capacity retention after 500 cycles. These enhanced electrochemical features areattributable to the unique hierarchical composite microspheres with uniformdistribution of graphene nanosheets among MoS2 layers.In summary, a molybdenum disulfide .


The goal of the current study is to clarify the relationship between social information processing  and aggressive tendencies. Thirty adults were recruited in the eye-tracking study that measured various components in social information processing. Baseline aggressive tendencies were measured using the Buss-Perry Aggression Questionnaire (AQ). Visual attention towards hostile objects was measured as the proportion of eye gaze fixation duration on cues of hostility. Hostility attribution bias was measured with the rating results for emotions of characters in the images. The results show that the eye gaze duration on hostile characters was significantly inversely correlated with the AQ score and less eye contact with an angry face. The eye gaze duration on hostile object was not significantly associated with hostility attribution bias, although hostility attribution bias was significantly positively associated with the AQ score. Our findings suggest that eye gaze fixation time towards non-hostile cues may predict aggressive tendencies. Aggressive tendencies not only predict violent behaviors, but also self-injurious or suicidal behaviors ,2. UnravCognitive distortions have been thought to play a role in hostility attribution bias . Mood dyA total of 36 young adults (age range: 18–30 years) were recruited for this study. The exclusion criteria include (1) a history of psychotic disorders, (2) a history of depressive or bipolar disorder, and (3) a history of substance use disorders. We used the self-reported questionnaire to exclude the individuals with these four types of mental disturbances.Twenty-five of the 36 participants were recruited through on-line advertisement, and provided their consents by signing in the on-line spreadsheet. Another 11 participants were enrolled through the biorepository at Cincinnati Children’s Hospital Medical Center (CCHMC). This biorepository project has been conducted based on the protocol approved by Institutional Review Board (IRB) of CCHMC. The individual in this manuscript has given written informed consent (as outlined in PLOS consent form) to publish these case details.We used Buss-Perry Aggression Questionnaire (AQ) to assess the baseline aggressive tendencies . The queStimuli: We have designed a series of pictures to present embedded ambiguous signs of hostility in the context of social interactions to each participant. These social interactions were classified into two categories: “confrontational” and “non-confrontational.” During the confrontational session, a series of 10 pictures of facial expressions retrieved from MMI Facial Expression Database [Database  were preEye tracking experiment: Eye gaze patterns were recorded using the Eyelink II and analyzed using Eye Link® Data Viewer  according to the user’s manual. The area of interest (AOI) was determined by the research team to concentrate on the regions that were hypothesized to represent the target of social information processing. For images related to social interactions, the AOIs were defined as regions including the face of each character and other body parts that intuitively referred to the body language . For images of individual facial expressions, the AOIs included eyes, noses, and mouths, which were found to more frequently viewed than the other parts of the face [the face .2 = 0.2, and alpha-value = 0.05, we estimated that we would achieve the power of 0.71 with the sample size equal to 36. Therefore, our sample size might be adequate given that we aimed to obtain a moderate statistical power. The primary predictor variable was the eye gaze fixation time at each AOI. All key continuous variables  were normalized with inverse rank-based transformation before the further analysis. We used the step-wise regression model to select significant independent variables to partially remedy under-estimated coefficients due to multicollinearity. The relationship between aggressive tendencies (AQ scores) and eye gaze fixation times was examined using the general linear model with PSS scores, gender, and age being adjusted as covariates. The area of AOI was adjusted in the regression model. Two-sided alpha value = 0.05 was used as the cut-off to screen for significant association findings. We later performed single-value permutation tests  to generate empirical p-values in order to alleviate inflated type-I errors due to multiple tests. We also test spatial homogeneity for eye gaze fixation points in the AOI with Ripley’s K functions. The measure of the degree of spatial homogeneity was used to examine whether the degree of “attention dispersion” correlated with the AQ score. Attention dispersion might be regarded as another aspect of visual attention.Under the assumption of effect size fOur findings suggest that selective visual attention towards objects with hostility may be associated with aggressive tendencies in young adults. Specifically, we found that individuals with greater aggressive tendencies seemed to pay more visual attention to the non-facial parts of the hostile character in the context of social interactions, compared to individuals with lower aggressive tendencies. This may lend little support to the hypothesis that selective visual attention to hostile objects can contribute to aggressive tendencies. Similarly, we found that individuals with greater aggressive tendencies seemed to pay more visual attention to non-eye regions of the angry face, compared to their peers with lower aggressive tendencies. This may imply that individuals with greater aggressive tendencies may show less eye contact when being faced with possible hostility, compared to their peers with lower aggressive tendencies. Taken together, aggressive tendencies appear to be inversely correlated with eye contact in response to the object of hostility. The association appears to be more remarkable when the individual interacts with another hostile individual than serving as a by-stander in the scene of social conflict.Eye contact indicates several different kinds of social communications. Previous studies have suggested that eye contact aversion often occurs in an aggressive encounter . In primTo evaluate if the data based on early short time-windows were different from the current results, we re-examined the eye gaze fixation points during the first 5 seconds. The results show that there was no statistically significant correlation between aggressive tendencies and region-specific fixation time. Our explanation is that the visual stimuli in the first 5 seconds might be primarily driven by immediate emotional response, which might not be able to sufficiently distinguish individuals with higher aggressive tendencies from individuals with lower aggressive tendencies. When the viewing time is extended, how visual attention is sustained towards certain regions might be able to distinguish individuals with higher aggressive tendencies from individuals with lower aggressive tendencies.The primary limitation of the current study is the sample size. The age range of our sample  and characteristics of participants (volunteer college students) may also discourage the generalizability of our findings. In addition, we did not perform stringent multi-testing corrections, such as Bonferroni method, and hence inflated type-I errors may remain to be a problem. However, we did perform single-value permutations to generate empirical p-values to identify significant associations, so inflated type-I errors may be partially alleviated. Finally, we relied on self-reported information to exclude subjects with mental disorders. The impact of under-reported cases of mental disorders may lead to uncertain directions of bias on our findings.Several recent studies also report neural correlates or eye gaze patterns in individuals viewing violent conflicts. Briefly, how an individual reacts to stressful stimuli  may be affected by several different factors, such as affective information in the background ,24. FurtIn conclusion, we have found that selective visual attention associated with hostile emotions might serve as a physiological/behavioral marker for aggressive tendencies in non-mentally ill individuals. Since aggressive tendencies may predict aggressive and violent behaviors, selective visual attention towards objects of hostility may also predict aggressive or violent behaviors. Replication of these findings in a larger population is needed to evaluate the clinical utility of eye gaze fixation time  in at-risk individuals. The findings may inform early detection and prevention modalities of aggressive/violent behaviors in the future. Previous evidence suggests that the patterns of visual attention bias towards hostility in healthy individuals seem to depend on the diagnosis of mental disorders. Further research is warranted to compare the cognitive and behavioral mechanisms underlying aggressive tendencies across different diagnoses.S1 Dataset(DOCX)Click here for additional data file.


This review article aims to provide an overview of chemically modified graphene, and graphene oxide (GO), and their impact on toxicology when present in biological systems. Graphene is one of the most promising nanomaterials due to unique physicochemical properties including enhanced optical, thermal, and electrically conductive behavior in addition to mechanical strength and high surface-to-volume ratio. Graphene-based nanomaterials have received much attention over the last 5 years in the biomedical field ranging from their use as polymeric conduits for nerve regeneration, carriers for targeted drug delivery and in the treatment of cancer via photo-thermal therapy. Both in vitro and in vivo biological studies of graphene-based nanomaterials help understand their relative toxicity and biocompatibility when used for biomedical applications. Several studies investigating important material properties such as surface charge, concentration, shape, size, structural defects, and chemical functional groups relate to their safety profile and influence cyto- and geno-toxicology. In this review, we highlight the most recent studies of graphene-based nanomaterials and outline their unique properties, which determine their interactions under a range of environmental conditions. The advent of graphene technology has led to many promising new opportunities for future applications in the field of electronics, biotechnology, and nanomedicine to aid in the diagnosis and treatment of a variety of debilitating diseases. There is only a relatively small contribution regarding the safety profile and toxicology data in the literature on graphene-based materials outlining their interactions in biological systems with cells and tissues. Over the last 5 years alone, over 424 publications and cited articles relate to graphene toxicology, which has increased to 1,015 publication by 2009 to approximately 3,753 in 2013, whereby the vast majority focus on the physical and material properties of graphene and is a subject of intensive research , rolled into 1D structures as a single-sheet CNTs, or stacked into 3D-layered structures such as graphite , mechanical, optical transmittance (~97.7 %), structural, and thermal behavior, and has shown great promise for many application areas relating to electronics, semiconductor fabrication, and the biomedical industry   at high temperature  using gasses such as methane –CH4 (g) as a carbon source as highlighted in Fig. 4 forms graphene on top of the Cu or nickel (Ni) foil . Further exfoliation with ultrasonication, thermal or energetic conditions help to oxidize stacked layers of hexagonally arranged carbon atoms that are bonded together with an inter-planar force to obtain graphene layers. The use of this method led to the formation and production of single-layer-reduced GO  bottom-up and 2) top-down fabrication techniques. Bottom-up fabrication is achieved using several methods to prepare high-quality graphene such as chemical vapor deposition (CVD). These methods produce highly crystalline graphene, but are not suitable for mass production  of graphite has been reported as 2 g/per kilo  is reacted with polyethylenimine-modified GO (PEI-GO) acting as a nanocarrier attached to the nanocrystals to yield PEI-GO–nanocrystal  converts light or optical energy to heat by absorption of a range of nanomaterial , leading to the thermal ablation resulting in the death of cancer cells. In recent years, PTT as a minimally invasive, controllable, and highly efficient treatment method has drawn widespread attention in the treatment of cancer. A large number of research groups have developed various light-absorbing nanomaterials as PTT agents  implants used in the peripheral and central nervous system (CNS). Nanoparticles incorporated into polymeric conduits, acting as fillers, such as, graphene, CNTs, and fullerene, can become one possible solution in the production of conducting materials, which are necessary for stimulating cell growth, and delivery of therapeutic agents. Identification of neural stem cell differentiation is an essential stage for the practical application of stem cell technology in regenerative medicine. Cell differentiation and monitoring is incredibly important for the application of neural stem cells (NSCs) in the treatment of neurodegenerative disease such as Alzheimer’s , morphology, geometry and aggregation behavior and solubility will influence the particle distribution within the surrounding environment. Nanoparticles when present in physiological fluids such as plasma or serum redistribute themselves throughout the host tissues and are transported to the liver, lungs, spleen, heart, kidney, and bone marrow due to their material and surface properties, and how they interact as a consequence of proteins that adsorb on to the surface can cause nanoparticle aggregation and cell uptake , as a result of environment toxicity or in vitro or in vivo medical treatments using graphene either as an implantable device or as drug delivery carrier. Animal experiments are performed according to policy guidelines standardized by the Organization for Economic Co-operation and Development (OECD) in the UK, and are known to determine common toxic characteristics of a broad range of materials and chemicals. This includes eco-toxicity or animal and human toxicity.Toxicology studies are now becoming more advanced in small- and large-scale animal studies in vivo and human cell lines in vitro. Direct hazard assessments and current methodology for studying nanomaterials help to reveal gaps in the knowledge and deficiency of current assessments. For example, the lethal dose (LD50) of graphite, CNTs, and fullerenes reported as 2 g/Kg , epoxy (–C–O–C–), and hydroxyl (–OH) functional groups. Moreover, limitation of GO use in a variety of biomedical applications is due to the absence of stable dispersions. In the following sections, we review current nanotoxicity studies carried out with GO over the last 5 years. Moreover, Tables GO is water-soluble nanomaterial and has been investigated extensively as a material for industrial applications for electronics and use in biomedical engineering. This is due to the large vacancy of planar surface area for efficient filling of aromatic drug molecules through 2) groups, whereas linear PEIs contain all secondary amines. The production of linear PEI-grafted GO (LP-GO) conjugates, and their efficacy to transfer nucleic acids into the mammalian cells is investigated  with the loading ratio more than 100 %  (GO/TiO2) hybrid (GOT) was studied by using Ti (OC4H9)4 and GO as reactants. The result presented no toxicity of GO in vitro as an electron sink in GOT efficiently increased the photodynamic therapy (PDT) activity  cells based on current data has shown that at low concentrations, GO does not enter into the cells and shows no signs of cytotoxicity. However, GO is known to be cytotoxic and is dose-dependent and known to cause oxidative stress in A549 cells, and induce a loss in cell viability at high concentrations , ZnO, TiO2, tin (Sn), and CNTs at concentration higher than (100 μg/mL). Graphene concentrations higher than 1 μg/mL induced DNA damage at a significantly lower concentrations  and TRC105 (an antibody that binds to CD105)  loaded onto PEG-functionalized graphene oxide (GO) via supramolecular π–π stacking investigated and obtained GO–PEG–HPPH complex, shows high HPPH loading efficiency. The in vivo distribution and delivery were tracked by fluorescence imaging as well as positron emission tomography (PET) after radiolabeling of HPPH with 64Cu. Compared with free HPPH, GO–PEG–HPPH offers dramatically improved photodynamic cancer cell killing efficacy due to the increased tumor delivery of HPPH  system including liver and spleen were observed post-injection (i.p.) and are highlighted in Fig. Functionalized GO toxicity and their distribution have been studied in mice using radiolabeling techniques ]) was investigated  that are able to distinguish intact and damaged DNA and catalytic activity of hemin through graphene π–π interactions have successfully synthesized. Based on this, for detection of single-stranded DNA (ss-DNA) and damage DNA induced by chemicals such as styrene oxide (SO), NaAsOo-methacrylate (FMA) to yield multi-functional graphene (MFG) with water dispersibility based on 2.5 mg/mL concentration  for linking the fluorescein Graphene-based nanomaterials have great potential for large number of future technologies ranging from biotechnological and biomedical applications including, drug delivery, PTT, and cancer targeting and therapy. Graphene materials are known to vary widely in terms of their physical and chemical properties such as their dimensions and chemical functional groups. Moreover, they possess unique physical and chemical material properties such as optical, electrical and thermal conductivity, and high surface-to-volume ratio. In addition, they can be easily linked to macromolecules through covalent or non-covalent attachment. The types of graphene material and their chemical modifications to produce novel graphene compounds provide different levels of dispersibility and impurities within the nanomaterials. Based on the previous toxicity investigations of graphene, graphene oxide and their derivatives all exhibit in vitro toxicity. However, it showed that cells are very sensitive to size, shape, solubility, and concentration of graphene nanomaterials. GO is considered more biocompatible than graphene due to its greater solubility/dispersibility, which results in less damage and toxicity in human cell types such as skin fibroblasts and red blood cells, and bacteria. Unfortunately, there are no current or sufficient in vivo studies outlining their nanotoxicity. The results indicate that upon initial exposure of the materials, the most prominent route into the human body lies within the respiratory system. However, they are less effective in liver, kidney, and spleen. Furthermore, all cells exhibit time and dosage dependency depending upon protein adsorption and reactions governed by aggregation. As this review represents only a few studies in relation to graphene-based materials, their toxicology profile remains at the very early stages of development for a range of biomedical applications. However, before such materials reach the clinic, their toxicology profile and safety efficacies are essential steps in their evolution. Such great potential will offer a variety of new and powerful tools based on graphene materials for use in the areas of advanced imaging, disease diagnosis, and targeted therapies for the treatment of a range of severely debilitating diseases.


GMC cultures were split into four groups treated for 24 h: Group N (blank control group), Group A (10−7 mol/L AngII), Group LT (10−7 mol/L AngII and 10−5 mol/L losartan), and Group Pred (10−7 mol/L AngII and 10−5 mol/L prednisone). GMCs proliferation was measured by the MTT and trypan blue assays. The distribution of TRPC6 was monitored by immunofluorescence, the expression of TRPC6 was detected by RT-PCR and Western blotting, and [Ca2+]i was measured by laser scanning confocal microscopy. The results showed that the maximal proliferation of GMCs was induced by treatment with 10−7 mol/L AngII for 24 h. In Group A, the distribution of TRPC6 was not uniform in the cell membrane, there was increased accumulation of this protein within the cytoplasm, and the increased expression of TRPC6 and [Ca2+]i was consistent with the proliferation of cells. In Group LT, losartan inhibited the proliferation of GMCs significantly, the levels of TRPC6 and [Ca2+]i were diminished, and the distribution of TRPC6 was improved. Prednisone also significantly inhibited the proliferation of GMCs and had no effects on the expression of TRPC6 and [Ca2+]i in Group Pred. These findings suggested that AngII could enhance the expression of TRPC6, increase [Ca2+]i, and demonstrate a time–dose–response relationship with the proliferation of GMCs, while losartan reversed the effect of AngII on GMC proliferation.This study investigated the changes in intracellular [Ca In the past 20 years, epidemiological studies have suggested an increase in the incidence of chronic kidney disease in children . Glomeru2+. TRPC6 is the core member of TRPC superfamily [2+]i  and is involved in a number of kidney diseases i and the involvement of ion channels in cell proliferation have become hot topics. In this study, GMC proliferation induced by AngII was observed. The expression of TRPC6 at the gene and protein level, as well as the relationship between cell proliferation and [Ca2+]i in the GMC proliferation process, was further investigated. Furthermore, the blocking effects of losartan were studied, and the mechanism of cell proliferation induced by AngII was explored from the perspective of ion channels.Transient receptor potential channel (TRPC) is a transmembrane protein that allows for transmembrane movement of Caerfamily , which mdiseases , 5.Changfibrosis –9. Previby AngII . Therefo2 at 37 °C and grew adherently in 20 % fetal bovine serum medium . Morphology was observed with an inverted microscope. GMCs at logarithmic growth stage were inoculated into six-well plates, fixed with paraformaldehyde for 30 min, and then blocked by goat serum  for 1 h. Afterward, GMCs were incubated with mouse monoclonal antibodies , including anti-desmin protein, anti-α-actin protein, anti-myosin protein, anti-vimentin protein, anti-keratin protein, and anti-factor VIII at 4 °C overnight. This was followed by inoculation with FITC-labeled goat anti-mouse IgG  at 37 °C for 1 h. GMCs were monitored and visualized by fluorescence microscopy. GMCs of 3–8 generations were used for further experiments.Glomerular mesangial cells  were cultured in incubators containing 5 % CO−8 and 10−7, 10−6 and 10−5 mol/L, were used to stimulate the GMCs for 0, 24, 48, and 72 h, respectively. Next, 10 μL of MTT  was added to each well and incubated at 37 °C for 4 h; afterward, 150 μL of dimethyl sulfoxide (DMSO) was added to each well. The optical density (OD) at 490 nm was measured by a microplate reader. After mixing the cells with a 0.4 % trypan blue solution for 3 min, the number of living cells and dead cells were counted with a hemocytometer. Proliferation rate (%) was calculated with the following formula: /OD value in blank control × 100 %. Cell viability (%) was calculated with the following formula: number of living cells/(number of living cells + number of dead cells) × 100 %.Cells were inoculated into 96-well plates. In the serum-free medium, cells adhered to the surface, and different concentrations of AngII , including 0 (blank control group), 10−7 mol/L of AngII to induce GMC proliferation for 24 h), the experiments were grouped as follows: Group N (blank control group), Group A (10−7 mol/L AngII), Group LT (10−7 mol/L AngII and 10−5 mol/L losartan), and Group Pred (10−7 mol/L AngII and 10−5 mol/L prednisone). Intervention groups (Group LT and Group Pred) were pre-treated by losartan or prednisone, respectively, for 1 h prior to the addition of AngII. Inhibition rate (%) was calculated with the following formula: /OD value in group A × 100 %.After determining the optimal concentration and time of AngII treatment , and mixed with rabbit anti-mouse TRPC6 polyclonal antibody . After overnight incubation, FITC-labeled goat anti-rabbit IgG  was added, and the distribution of TRPC6 was observed by immunofluorescence microscopy.Total RNA was extracted with the addition of Trizol reagent  into all groups. cDNA was synthesized using 1–2 μg of total RNA. The primers were designed using the Primer Express software (Primer Premier 5.0) based on sequences obtained with the GenBank accession numbers. The sequences of the primers and amplicon sizes are shown in Table Cell lysis solution was added into the cells of each group. The protein concentration was determined by the bicinchoninic acid (BCA) method. Thirty five micrograms of total protein was denatured at 100 °C for 5 min, run on a 120 g/L sodium dodecyl sulfate polyacrylamide gel  for 1.5 h, and then wet transferred to a polyvinylidene difluoride  membrane. The membrane was blocked with 5 % non-fat milk at room temperature for 30 min, followed by incubation with rabbit anti-mouse TRPC6 polyclonal antibody  at 4 °C overnight. The membrane was subsequently incubated with HRP-labeled goat anti-rabbit IgG  at room temperature for 1 h. After the final rinse, the membrane was visualized with an enhanced chemiluminescence reagent and exposed to X-ray films. Band intensity was estimated using Gel-Pro image analysis software. The relative expression levels of target proteins were calculated as the ratio of the target protein band intensity to that of the internal control GAPDH.−6 mol/L of Fluo-3AM  at 37 °C for 45 min. Following this step, cells were inoculated into special culturing dishes for laser scanning confocal microscope (LSCM) and washed with D-Hanks three times. Then, the measurements were taken by LSCM with the excitation wavelength set at 488 nm. The [Ca2+]i was scanned per 5 s for 10 min, with each scan covering 20 cells. The results were analyzed by Zeiss image 4.2 software. The [Ca2+]i was calculated with the following formula: F/Fa .Cells from each group were re-suspended with 5 × 10P value <0.05 was considered to be statistically significant.All values were expressed as mean ± SD, and analysis of variance was calculated using SPSS 11.5 statistical analysis software. Fisher’s LSD test was used for the pairwise comparison. A GMCs grew adherently and showed larger soma with fusiform, irregular star-shaped, or elongated shapes. There were several dendrites of various lengths on the cell, which connected the cell groups into a network with a round- or egg-shaped cell nuclei in the middle. The GMCs stained positive for desmin, α-Actin, myosin, and vimentin and negative for keratin and factor VIII, indicating that the cultured cells were in fact GMCs Fig. .Fig. 1Im−8 mol/L AngII, while addition of 10−7, 10−6, and 10−5 mol/L of AngII caused increased cell proliferation at 24, 48, and 72 h; the proliferation at 24 h was much more significant than that at 48 h and 72 h . In addition, at 24 h, the proliferation with AngII at 10−7 mol/L was of greater statistical significance than that observed with AngII at 10−8, 10−6, and 10−5 mol/L (P < 0.01) . Furthermore, compared with Group A, the GMC proliferation was significantly inhibited in Group LT and Group Pred  ; when compared with Group A, the expression of TRPC6 mRNA in Group LT was diminished (P < 0.01), and there existed no significant difference in Group Pred (P > 0.05) P < 0.01); as compared with Group A, the expression of TRPC6 protein in Group LT declined (P < 0.01), and no significant difference in Group Pred was observed (P > 0.05) 2+]i increased significantly after the addition of AngII. The fluorescence intensity began to increase at the third min and peaked at the fourth minute. The fluorescence began to decrease 1 min later and returned to the starting level at the eighth minute ; as compared with Group A, [Ca2+]i decreased in Group LT (P < 0.05), and there was no significant difference in Group Pred (P > 0.05).After incubation with Fluo-3AM, a calcium indicator, green fluorescence was uniformly distributed in cells Fig. . The i can promote the proliferation of GMCs; for example, AngII can increase [Ca2+]i by signal transduction pathways, which in turn regulates cell proliferation [2+]i and the proliferation of GMCs are significantly inhibited i reached the maximum level at the forth minute after incubation with AngII. These observations suggested that TRPC6 and Ca2+ played important roles in the process of GMC proliferation. After incubation with losartan, TRPC6 distribution was improved, and [Ca2+]i was consistent with the cell proliferation, indicating that AngII affected TRPC6 and Ca2+ through AT1R, and further regulated cell proliferation. Prednisone inhibited cell proliferation, but had no effect on the expression of TRPC6 and [Ca2+]i, indicating that cell proliferation was not necessarily caused by changes in [Ca2+]i. It had been reported that glucocorticoid does not cause the changes in [Ca2+]i, and that its effects on cell proliferation could be achieved by inhibiting nuclei factor NF-κB or increasing P21 protein to arrest the cell cycle of GMCs at G0/G1 i in GMCs, which in turn induced its proliferation. The mechanism by which this occurs begins with the binding of AngII to AT1R on the surface of GMCs, which causes phospholipase c (PLC) to catalyze the cleavage of 4,5-phosphatidyl inositol diphosphate (PIP2), producing 1,4,5-inositol triphosphate (IP3). IP3 can then activate Ca2+ channels, leading the flow of extracellular Ca2+ into the cell. This influx results in increased [Ca2+]i in the sarcoplasm, which in turn regulates transcription and causes the proliferation of GMCs. There exist target sites for AngII on the TRPC6 channel. Through TRPC6, [Ca2+]i can be increased by AngII stimulation. And it is possible that TRPC6 and AngII are relevant in terms of regulating GMC proliferation via controlling [Ca2+]i i and induced GMC proliferation shared similarities with the mechanism by which TRPC6 regulated [Ca2+]i, as both were associated with an IP3-regulated calcium channel, and TRPC6 mediated Ca2+ to flow inward to promote the proliferation of GMCs.AngII promoted the increase of [Ca [Ca2+]i . In the f a SOCC . These s


Epitaxial graphene has proven itself to be the best candidate for quantum electrical resistance standards due to its wide quantum Hall plateaus with exceptionally high breakdown currents. However one key underlying mechanism, a magnetic field dependent charge transfer process, is yet to be fully understood. Here we report measurements of the quantum Hall effect in epitaxial graphene showing the widest quantum Hall plateau observed to date extending over 50 T, attributed to an almost linear increase in carrier density with magnetic field. This behaviour is strong evidence for field dependent charge transfer from charge reservoirs with exceptionally high densities of states in close proximity to the graphene. Using a realistic framework of broadened Landau levels we model the densities of donor states and predict the field dependence of charge transfer in excellent agreement with experimental results, thus providing a guide towards engineering epitaxial graphene for applications such as quantum metrology. In these models the linear magnetic field dependence of n is predicted to saturate at high magnetic fields. However, further work has suggested that the carrier density continues to increase to much higher magnetic fieldsδ-function Landau levels in graphene and constant densities of states within the charge reservoirs. Experimental data in which the full extent of the magnetic field dependence can be measured is therefore crucial in obtaining a complete understanding of this process which underpins the benefits of graphene in quantum metrology. Using a combination of pulsed high magnetic fields up to 57 T and very low carrier density samples we present here the first detailed study of the full magnetic field dependence of charge transfer in epitaxial graphene through a ν = 2 plateau which remarkably extends from B = 3 T to over 50 T. We show that by using the occupancy dependence of the quantum Hall breakdown current we can demonstrate that the carrier density increases almost linearly throughout the ν = 2 plateau. This method is validated using a fit to the temperature dependence of the magneto-conductivity which provides a direct measure of the position of the Fermi energy with respect to the nearest (N = 0) Landau level and hence provides an independent measure of the carrier density. We also demonstrate that by extending the existing models1112In epitaxial graphene grown on the Si-terminated face of SiC, charge transfer from the underlying substrate to the graphene leads to a strongly magnetic field dependent carrier density and an exceptionally wide quantised 10 cm−2, as determined from the low field Hall coefficient ν = 2 quantum Hall state is observed to begin well below 1 T and the longitudinal resistivity, Rxx is undetectably small from 0.7 T up to 14 T, as shown in jc = Ic/W a sudden onset of longitudinal resistance indicates the breakdown of the quantum Hall effect. The value of jc is defined as the current density above which Vxx > Vc, where the critical voltage Vc is determined by the noise limit of the measurement. It can be extracted from the I − Vxx characteristics in the quantum Hall state, as shown in Vc = 0.5 μV. By measuring the breakdown current as a function of magnetic field throughout the ν = 2 plateau we are able to extract a wealth of data, in particular about the magnetic field dependent carrier density.We begin with the sample having its lowest density, where the zero field carrier density is 1.5 × 10jc centred exactly at an integer filling factor (e.g. ν = 2) falling linearly to zero at the edges of the plateau (approximately ν = 2 ± δν)2324In traditional semiconductor quantum Hall systems, where the carrier density is constant, the breakdown current has been shown to have a triangular dependence on both filling factor and magnetic field, where a sharp peak is observed in δν is typically in the range 0.2 < δν < 0.32324N = 0 or N = 1 Landau level become energetically easier to access, dissipation occurs at progressively lower measurement currents until jc decreases to zero. In order to explain the extremely wide plateaus observed in graphene both here and previously312ν = 2 state changes only slowly with magnetic field thus creating an asymmetric and very broad jc profile along the plateau (where  plateau .σxx) of this sample. The longitudinal conductivities as functions of inverse temperature from 1.4 to 200 K for a series of magnetic fields are shown in σxx is linear with 1/T. In contrast, the non-linearity of the log σxx − 1/T plot at low temperatures shows the importance of variable range hopping (VRH) which causes significant deviations from the conventional Arrhenius activation behaviour. Excellent fits to the total longitudinal conductivity can be achieved however by combining thermal activation between extended states in adjacent Landau levels and VRH. The total conductivity is calculated as,In order to produce a quantitative measurement of the magnetic field dependent carrier density, we have studied the temperature dependence of the magneto-conductivity  which comes mainly from σTA, dominant at high temperatures. No significant difference in EF is found by using either the Mottwhere T0 is a fitting parameter. In terms of σTA, obtaining a simple analytic formula can be difficult, especially when characteristics of Landau level broadening are taken into account2829where the characteristic temperature gv = gs = 2 are the valley and spin degeneracies, EN is the energy of the Nth Landau level, and the standard deviation s represents the Gaussian broadening of a Landau level. In our case the thermal energy is small compared with the Landau level separation and the only contributions are from the extended states within the mobility edges (EN ± Eμ) at the centres of the N = 0 and N = 1 Landau levels. Since the Fermi level EF is also well within the region of localised states, from the Kubo formulawhere k = γβ(EN − EF) − (βs/2)2, where N = 0 and N = 1 Landau levels have fixed Gaussian broadening, i.e., s and Eμ are constants independent of magnetic field and temperature. The value of s is chosen to be ~12 meV in order to match the energy scale of the low-field Gaussian random disorder potentials in these systemsEμ is determined to be 7.8 meV  by fitting the data for B = 1.2 T, where EF is known to be exactly at the mid-point between the two Landau levels since at elevated temperatures the minimum in conductivity and Rxx is observed at this field. We also note that the dimensionless parameter EF is a slowly decreasing quantity which approaches the mobility edge Eμ gradually. This suggests that the magnetic field dependent charge transfer rate is slightly lower than the increase in the total Landau level DOS. EF as a function of magnetic field is given by G(E) is given by Employing the above formulation, the temperature-dependent magneto-conductivities are very well fitted across a broad temperature range from 1.4 up to 200 K, as shown in In order to provide a quantitative relation to describe the charge transfer which can be compared to the magnetic field dependence of the breakdown current, we introduce the following phenomenological expression for the field dependent carrier density,p, B0 and Bc are fitting parameters. This expression is chosen as, for large values of p, it rapidly swaps over from a constant carrier density n0 at low field, where ν = 2 would occur if there were no charge transfer at this low field carrier density, to a slightly sublinear increase with field Bc is the magnetic field corresponding to ν = 2 including the additional charge transfer. The carrier density and occupancy predicted by this equation for this sample are shown in p = 13. Using the analytical form for n given by p = 5, 10, 15 and 20, which demonstrate the appearance of a strong asymmetry as a function of field and a very considerable broadening of the breakdown current field dependence. jc to the data deduced from p = 13 which gives an excellent description of the data. We use p = 13 in all subsequent fitting. The magnetic field at which jc goes to zero (14 T) corresponds to an occupancy as deduced from the temperature dependence of σxx of 1.74  current of 3 μA in a 57 T long pulse magnet. At both positive and negative magnetic fields the magnetotransport is dominated by the extended ν = 2 plateau. Using the low field Hall coefficient we extract an initial carrier density of 1.5 × 1011 cm−2. Also at low magnetic fields we observe a clear weak localisation peak in the resistivityν = 6 and ν = 10  from ref. and,ϵ1(2), γ1(2), and d1(2) are the absolute permittivity, the assumed constant DOS of surface donor states, and the distance between graphene and the donor states for the SiC/graphene (graphene/PMMA) interface, respectively  =  (ϵ0 = vacuum permittivity), d1 = d2 = 0.3 nm, we plot the relation between γ1 and γ2 in γ1) decreases from 30% to 0% of the total DOS in the two charge reservoirs, γ2 will rapidly increase to infinity. It is not physical to have such a large DOS in the PMMA interface (γ2), so it is unlikely that γ1 + γ2 remains roughly constant over a large range, γ1 ~ 0.8 − 1.7 × 1014 cm−2 eV−1, γ2 ~ 0.3 − 1.3 × 1014 cm−2 eV−1, with γ1 + γ2 ~ 2 × 1014 cm−2 eV−1. Our estimation suggests that the surface states in SiC play a more significant role in the charge transfer process. The surface states responsible are closely related to the large number of atomic defects (vacancies and adatoms) predominantly located in the first underlying atomic layer, which consists of a non-conductive surface reconstruction of carbon atoms covalently bonded to the SiC which is formed during the growth process3738394041424344EF3740434415 cm−2 for the reconstructed layer leads to DOS in the range of 0.8 − 1.5 × 1014 cm−2 eV−1. Despite the variations in experimental conditions, the reported values are consistent with our estimate for γ1. For the graphene/PMMA interface, we attribute the less significant but still relatively high γ2 to the increased number of charge traps introduced by the intensive UV treatment2021Bc (the magnetic field corresponding to the occupancy ν = 2 where the minimum Rxx and the maximum jc occur) as a function of the zero field carrier density. Based on Another important consequence from our model is that we can deduce vF is the Fermi velocity. The left hand side and the right hand side of the equation represent the charge equilibrium at B = 0 and B = Bc, respectively, with EF being B = 0, and at the mid-point between the N = 0 and N = 1 Landau levels Bc. The solution to B0 (red lines) in Bc = B0, which represents the case of a constant carrier density without the field dependent charge transfer. Combining ν = 2 plateau occurs, using B0 as shown in the where nmax that can be transferred into graphene, corresponding to the limit B → ∞ and EF → 0 when other high magnetic field effects  are neglected. From Finally, we calculate the maximum carrier density or,nmax and n0 are both in units of 1011 cm−2. This relation is shown in nmax represents the upper limit to the possible validity of B → ∞. In practice, the highest carrier densities reached in our measurements, nmax due to the finite magnetic field strength we could apply. Therefore, in this regime, n(B).where Bc, nmax) of the breakdown of the quantum Hall effect and the field dependent charge transfer, using just the zero field carrier density (n0 or B0). These results can thus provide realistic references for the optimum operating conditions for a quantum Hall resistance standard using epitaxial graphene. We emphasise that our model can ultimately provide a complete n(B) dependence, if the exact details of the Landau level broadening are known. Such dependences are simulated in n0 listed, by numerically solving the equation set,Hence, with our model using a realistic framework of broadened Landau levels, we have been able to relate and accurately predict some of the most important characteristics (G(E) is the DOS of Landau levels. In this simulation, we continue to assume Gaussian Landau level broadening, such that G(E) is given by s = 12 meV of the Gaussian broadening for the same sample (n0 = 1.5 × 1010 cm−2) on which the temperature dependent measurements were made. For the samples with n0 = 1.5 and 8.7 × 1011 cm−2 in which s is unknown, our model suggests values of about 25 and 30 meV, respectively, both well within the normal range among similar samplesn(B) dependences given by our charge transfer model (dashed lines), and the those given by p = 13 (solid lines). At high enough magnetic fields, the inset to nmax as given by where v = 2 plateau can be observed in this system for low enough starting densities, n0, and demonstrate the very large extent of the magnetic field dependent carrier density in epitaxial graphene. We have shown that the quantum Hall effect breakdown current can be used to accurately measure this increase in carrier density with field, which is found to be over an order of magnitude in some cases. Using the models that we propose, we have been able to accurately describe and predict some of the most important features of the field dependent charge transfer process and its effects on the quantum Hall breakdown. Our models and results are widely applicable towards a broader and deeper understanding of the high magnetic field transport properties of graphene and are crucial for engineering epitaxial graphene devices for applications such as quantum Hall metrology.In summary, we have studied the breakdown and the temperature dependence of the quantum Hall effect using high magnetic fields and very low density epitaxial graphene grown on SiC. Our new measurements show that the full width of the W = 20 μm and length L = 20 μm. Electrical contacting was made using large area electron beam evaporated Ti-Au. A non-volatile dual-polymer gating technique using PMMA/MMA and ZEP520A was applied to tune the carrier density in the epitaxial graphene using a combination of UV illuminationT = 2 K unless otherwise stated.The devices studied were prepared from epitaxially grown graphene on the Si-terminated face of SiC. Each device was patterned using electron beam lithography and oxygen plasma etching into an eight-leg Hall bar geometry with a width How to cite this article: Alexander-Webber, J. A. et al. Giant quantum Hall plateaus generated by charge transfer in epitaxial graphene. Sci. Rep.6, 30296; doi: 10.1038/srep30296 (2016).


Based on the experimental data, the most probable structure of the complexes is suggested. In the present study, we have examined cytotoxic activity of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2) and their Pt(II) complexes on the retinoblastoma cell line WERI-Rb-1.This paper presents a method for synthesis and cytotoxicity of new platinum(II) complexes of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2). The new obtained complexes were studied by elemental analysis: ultraviolet–visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and  The profound interest on different hydantoin derivatives stems from the well-established medical applications of some hydantoin derivatives as antiepileptic drugs. Recently1H- and 13C-nuclear magnetic resonance (NMR) spectroscopy) .. Furthermore, considering literature review and biological activity of fluorenylspirohydantoins, the study of the possible effects that these compounds may have on the viability of human tumour cells (WERI-Rb-1) is particularly interesting.The aim of this study is to present a method for synthesis of new platinum(II) complexes of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2), its isolation in pure form and its characterization using various spectral methods (ultraviolet–visible (UV–vis), attenuated total reflection Fourier transform infrared (ATR-FTIR), and 1H- and 13C-NMR for Pt(II) compounds and additionally Raman spectroscopy for free ligands .In the present work, we studied the complexation properties of (9′-fluorene)-spiro-5-hydantoins and its 2-thio derivative see . The rea4)2[PtCl4] – Sigma-Aldrich) and solvents used for synthesis of the complexes were with a p.a. qualification. The two organic ligands L1 and L2 were synthesized according to methods described in Marinov et al. [A metal salt  of (9′-fluorene)-spiro-5-hydantoin (L1) in 10 cm4)2[PtCl4] in 10 cm3 H2O;0.0002 mol (0.0746 g)  of (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2) in 10 cm4)2[PtCl4] in 10 cm3 H2O;0.0002 mol (0.0746 g)  and the stirred crystals of L1, L2, Pt(II)L1 and Pt(II)L2 were pressed by an anvil to the reflection element. The Raman spectra of L1 and L2  were measured on a RAM II (Bruker Optics) with a focused laser beam of 500 mW power of Nd:YAG laser (1064 nm) from 4000 to 100 cm−1 at a resolution of 2 cm−1 with 25 scans. The NMR spectra were taken on a Bruker Avance II+ 600MHz NMR spectrometer operating at 600.130 and 150.903 MHz for 1H and 13C, respectively, using the standard Bruker software. Chemical shifts were referenced to tetramethylsilane (TMS). Measurements were carried out at ambient temperature.Electronic spectra of absorption were registered on a Lambda 9 Perkin-Elmer UV/vis/NIR(Near infrared) Spectrophotometer from 200 nm to 1000 nm. ATR-FTIR spectra were registered on a VERTEX 70 spectrometer (Bruker Optics) from 4000 to 600 cmThe physicochemical and spectral characterizations of the obtained compounds were as follows:2.The retinoblastoma cell line (WERI-Rb1) was purchased from ATCC-HTB-169. It was cultured in RPMI 1640, containing 10% FCS, streptomycin and penicillin at 37 ºC in a humidified atmosphere containing 5% CO4 cells/well. After a cultivation period of 24 h, the compounds were added at a concentration of 100 μM and incubated for 24, 48 and 72 h, respectively. WST-1 was added to the cells at these time points and incubated for 4h. WST-1 is a colorimetric assay for the non-radioactive quantification of cell proliferation, viability and cytotoxicity. The highest achievable concentration at which we were able to test it was only 100 μM.The cytotoxic effect of L1, L2, Pt(II)L1 and Pt(II)L2 was assessed on a retinoblastoma cell line using WST-1 assay . All compounds were first dissolved in DMSO and then diluted in the culture medium. The concentration of DMSO in the wells did not exceed 1%. Cells were seeded in triplicates in 96-well plates at a density of 6.5 × 10Absorbance was measured on ELISA SUNRISE Reader. The wavelength for measuring the absorbance of the formazan product is 450 nm and the reference filter was set at 620 nm in accordance with the WST-1 manual. Cells grown in culture medium alone and in appropriate concentrations of DMSO were used as controls. The percentage of viable cells was calculated as a ratio of the OD value of the sample to the OD value of the control. The data are presented as mean ± standard error of the mean.4)2[PtCl4] at molar ratio M:L:OH− = 2:4:1 for PtL1 and 1:2:3 for PtL2. Neutral complexes were synthesized and isolated as brown and yellow precipitates, respectively. All complexes were investigated by elemental analysis: UV–vis, ATR-FTIR, and 1H- and 13C-NMR spectroscopy.Complexation with Pt(II) was conducted under alkaline conditions using a metal salt namely L1 and Pt(II)L2 complexes were observed at 227 nm, 276 nm and 222 nm, 230 nm, 273 nm, respectively. Solid ATR-FTIR spectra of the free ligand and its complexes were recorded in order to clarify the structure of the formed metal complexes and to determine the coordination modes of the ligand. All vibrational frequencies observed in the ATR-FTIR spectra of the complexes and the free ligands were given in “Materials and Methods” section. The bands at 3360 and 3189 cm−1 of the free ligand L1 may refer to the stretching vibrations of two N–H groups of the hydantoin ring. In the ATR spectrum of the PtL1 complex, the same bands were observed at 3232 and 3136 сm−1 which shifts to lower frequency by 128 and 53 сm−1 as compared to the corresponding free ligand bands. The bands of free ligand L1 at 1775 and 1715 сm−1 can be attributed to the stretching vibration of C4 = O and C2 = O groups of the hydantoin ring. The same bands in ATR spectrum of PtL1 complex were at 1774 and 1705 сm−1, i.e. a slight change is observed. This fact shows that the two carbonyl groups of the ligand hydantoin ring did not participate in the coordination.The elemental analyses data showed metal-to-ligand ratio 1:6 for PtL1 and 1:2 for PtL2. The UV–vis spectra were registered in DMSO. Maxima in the UV–vis spectra of the free ligands L1 and L2 were observed at λ−1 (shoulder) and 3153 cm−1 were observed which may refer to the stretching vibrations of N–H groups of the hydantoin ring. These bands disappeared in the spectrum of the PtL2 complex; there was a very wide, low-intensity band between 3500 and 2500 cm−1. On the whole, all bands in the ATR spectrum of PtL2 complex were wider than those in the free ligand. In the spectrum of L2, there were bands at 1751 and 1729 сm−1 and 1530 сm−1; the first two bands can be attributed to the split stretching vibration of C4 = O, and the second to stretching vibration of C2 = S group. For the PtL2 complex, the first two bands were shifted by 21 and 23 сm−1 to 1772 and 1752 сm−1, respectively. On the other hand, the thiocarbonyl stretching was shifted by only 3–1527 сm−1. This fact shows that the thiocarbonyl group did not participate in the coordination with metal ion. Based on the experimental data, the most probable structure for the PtL1 complex was suggested with two deprotonated NH groups of ligand L1 and four uncharged organic ligands molecules. For the PtL2 complex square planar geometry was suggested with two ligand molecules coordinated in a bidentate fashion.In the ATR spectrum of the free ligand L2, the bands at 3244 cmOur results revealed that L1, Pt(II)L1 and Pt(II)L2 had a cytotoxic effect on the human retinoblastoma cell line WERI-Rb1  and  3. in vitro experiments are required to study the possible applications of hydantoin derivatives and their mechanism of action.Based on these results further 1H- and 13C-NMR spectroscopy, confirmed their structures. The preliminary results of our study showed that L1, Pt(II)L1 and Pt(II)L2 exhibit anticancer activity in vitro.The synthesis of two Pt(II) complexes with (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2) were described and the various spectral data, UV–vis, ATR-FTIR, and


A proportion of Alzheimer's disease cases displays inclusions of the RNA-binding protein, TDP-43. Considering the pathogenic role of tau mis-splicing, we compared tau isoform expression between Alzheimer's disease cases with or without TDP-43 inclusions. The average ratio of tau isoforms containing or lacking exon 10 (4R/3R ratio) or the total level of tau mRNA was not significantly different between cases with or without TDP-43 pathology in any of the brain regions examined. Although TDP-43 functions may be affected, TDP-43 does not critically regulate expression or splicing of tau in Alzheimer's disease suggesting that TDP-43 contributes to Alzheimer's disease through mechanisms independent of tau. In addition, 20%–30% of AD cases display cytoplasmic inclusions of transactive response DNA-binding protein of 43 kDa (TDP-43). The presence of TDP-43 inclusions in the hippocampus and entorhinal cortex correlates with neuronal loss in late onset dementia and, furthermore, a strong correlation exists between the presence of TDP-43 pathology and specific clinical features of AD, especially impaired cognition and amnesia . TDP-43 2t test.Frozen brain tissue was obtained from individuals free from neurological disease and individuals with AD and controls. Cases were assessed for TDP-43 pathology by immunocytochemistry. RNA was extracted using the Qiagen RNeasy/lipid kit (Qiagen). Tau E10 splicing was analyzed by end-point reverse transcription polymerase chain reaction using a forward primer 5′-labelled with an infrared fluorescent dye, yielding a signal independent of the length of the individual products. Gels were imaged, and polymerase chain reaction products were quantified using an Odyssey Infrared Imaging System (LI-COR Biosciences) . Statist3We analyzed tau splicing in a cohort of 14 AD cases with (ADTDP+) and 15 AD cases without (ADTDP−) TDP-43 inclusions and 15 age-matched nondemented healthy controls . The amy4TARDBP gene, encoding TDP-43, have been linked to familial forms of amyotrophic lateral sclerosis (Mutations in the clerosis , thus arclerosis . Howeverclerosis . Whetherclerosis . ConsideThe authors declare that they have no conflict of interest.


It is found that the microwave reaction time has a significant effect on the microstructure of graphene/MnO2 composites, and consequently, the electrochemical properties of the supercapacitors based on graphene/MnO2 composites are strongly microstructure dependent. An appropriately longer microwave reaction time, namely, 15 min, facilitates a very dense and homogeneous microstructure of the graphene/MnO2 composites, and thus, excellent electrochemical performance is achieved in the supercapacitor device, including a high specific capacitance of 296 F/g and a high capacitance retention of 93% after 3,000 times of charging/discharging cycles.Graphene has attracted much attention since it was firstly stripped from graphite by two physicists in 2004, and the supercapacitor based on graphene has obtained wide attention and much investment as well. For practical applications of graphene-based supercapacitors, however, there are still many challenges to solve, for instance, to simplify the technological process, to lower the fabrication cost, and to improve the electrochemical performance. In this work, graphene/MnO81.05.ue; 78.67.Sc; 88.80.fh However, metal oxides usually have a high electrical resistance, thereby leading to a low power density, and the high cost of RuO2 also limits its wide applications. For the second group, they are usually used in double-layer capacitors because of their electrochemical stability and high accessible surface area. For the third group, polyaniline and polypyrrole [2 composite is such an alternative material.In recent years, with the deterioration of the environment and the scarcity of natural resources, more and more researchers have turned their attention to the field of energy. Supercapacitor, serving as a novel energy storage device, is one of the mostly focused topics. The materials for supercapacitors that have been intensively studied so far can be divided into three groups: transition metal oxides, carbon materials, and conductive polymers . In the ypyrrole  for instypyrrole . Due to 2 can form a pseudocapacitance, thereby increasing the capacitance of the capacitor. To prepare graphene more simply and more safely, and finally to make the mass production come true, various methods have been developed [4 in a pH-neutral solution is expressed as follows [Owing to its high specific surface area, remarkable chemical stability, and superior electron mobility ,7,8, graeveloped , includieveloped , chemicaeveloped ,15, preseveloped , epitaxieveloped , and cheeveloped -20. In teveloped . The red follows :2 composite solution directly for a period of time to coat the active material on a current collector. Moreover, the process-structure-property relationships were systematically investigated for the graphene/MnO2 composites. Interestingly, it was found that the microwave reaction time has a significant effect on the microstructure of graphene/MnO2 composites and the electrochemical properties of the supercapacitors based on graphene/MnO2 composites are therefore strongly microstructure dependent.It is noteworthy that a simple method was used here for the supercapacitor packaging, i.e., dipping Ni-foam into a graphene/MnOGraphite oxide (GO) was synthesized firstly from natural graphite according to a modified Hummers method . A GO so2 composites were prepared by a redox reaction between graphene and potassium permanganate under microwave irradiation [4 powder (0.95 g) was added into the graphene suspension and stirred for about 10 min. Subsequently, the resulted suspension was heated using a household microwave oven  for several minutes, and then cooled to room temperature naturally. Finally, the black deposit was filtered and washed several times with distilled water and alcohol, and then dried at 80°C for 6 h in a vacuum oven. Different microwave reaction times, namely, 5, 10, and 15 min, were selectively used to study its effect on the microstructure and the electrochemical properties of the graphene/MnO2 composites. Due to the lab condition restriction and, more importantly, in order to avoid the overflowing of the reaction solution, we did not extend the microwave reaction time further.Graphene/MnOadiation . In the 2 composites were measured by X-ray diffraction  using Cu Kα radiation (λ = 0.154056 nm). The microstructure was characterized by scanning electron microscopy  and transmission electron microscopy . Note that the samples were dispersed in alcohol and dropped on a holey copper grid for TEM observations. The electrochemical measurements  were measured by using an electrochemical station  with a two-electrode system, which consists of two identical working electrodes in 6 M KOH alkaline electrolytes.The crystallographic structures of the graphene/MnO2 composite, carbon black, and polytetrafluoroethylene (PTFE), were mixed in a mass ratio of 75:20:5 and dispersed in ethanol [The fabrication of working electrodes was carried out in the following way. Briefly, the materials, including graphene/MnO ethanol . Then th2 composites with different microwave reaction times . It can be seen that the as-prepared graphene shows a weak and broad diffraction peak at 2θ = 23°, corresponding to the diffraction of the (002) plane. For the three graphene/MnO2 composite samples, their XRD patterns are almost the same, exhibiting a weak and broad peak of the (002) plane centered at 2θ = 23° (indexed for graphene) and two weak peaks indexed for α-MnO2 at 2θ = 37° (211) and 2θ = 66° (002) [θ ~ 43°, corresponding to the (100) crystal plane of graphene, cannot be observed after the deposition of MnO2, indicating that the surfaces of graphene were fully covered by nanoscale MnO2 and thus a lower degree of graphitization was induced, which was similarly reported by Yan et al. [2 composite samples have similar chemical compositions. To know more about the influence of microwave reaction time on the graphene/MnO2 composites, their microstructure and electrochemical properties have been systematically investigated, as will be discussed below.Figure Figure 6° 002) . The pea2θ = 37° 1 and 2θ  . The pe2 composites prepared with different microwave reaction times. Judging from Figure 2[2 nanoneedles grew almost on the whole graphene surface. Especially from the high-magnification TEM images , galvanostatic charge/discharge (CD), and electrochemical impedance spectroscopy (EIS) tests using a two-electrode system. To avoid complex steps, we adopted a simple method of dipping directly the as-prepared Ni-foam into the suspension of graphene/MnO2 composite, carbon black, and PTFE to prepare electrode slices. This method is simple to operate, and the active materials are not easy to fall off once they have been coated on Ni-foam. Furthermore, the active materials are relatively well distributed. However, there is also a disadvantage, that is, it is hard to control the mass of the active materials. Hence, we cannot get the difference in specific capacitance directly just by looking at the CV and CD diagrams since the mass of the active materials is different in those three samples. Nonetheless, the mass of the active materials can be calculated out by comparatively weighing the Ni-foam before and after coating the active materials, and the specific capacitance can be therefore obtained for each supercapacitor device.To characterize the electrochemical behavior of the button-type supercapacitor based on graphene/MnO2 composites with various scan rates in the range of 5 to 100 mV/s within a 0 to 0.8-V voltage window. It is well known that the more similar the shape of the CV cycles of a supercapacitor to a rectangle, the lower the contact resistance of the supercapacitor [2 gets firstly a little larger and then smaller again, but always tends to distribute more uniformly on almost the whole graphene sheet, and thus the relatively less stacking of graphene might be achieved as well. This could increase the specific surface area, thereby enhancing the electrical conductivity of the device.Figure apacitor ,26. As tapacitor ,28. The 2 composites. All the CD curves are linear and symmetric in the voltage range 0 to 1 V, indicating very good electrochemical properties of the graphene/MnO2 composite electrodes [Figure ectrodes . Using tI is the change/discharge current, t is the discharging time, m is the mass of the active material of two electrodes, and V is the voltage window after the deduction of the IR drop. Accordingly, as the microwave reaction time increases from 5 to 15 min, the specific capacitance at a charging current of 2 mA reaches 246, 260, and 296 F/g, respectively. As aforementioned, though the mass of the active material in each device is different, we can get the specific capacitance values similarly through calculating the data in CV curves. The enhancement of specific capacitance with increasing the microwave reaction time is believed to stem from the improved microstructure, as mentioned above. The results obtained in this work are comparable to or even higher than those reported in the literature for similar graphene-based material systems, where the specific capacitance was reported to be about 200 to 300 F/g [where  300 F/g .2 electrodes with different microwave reaction times, measured in a 6 M KOH alkaline electrolyte solution. The horizontal axis intercepts at high frequency in the Nyquist plots for the devices with microwave times 5, 10, and 15 min are, respectively, 0.70, 0.65, and 1.13 Ω, indicating that with the change in microwave reaction time, the electronic resistance (Rs), including the ionic resistance of the electrolyte, the intrinsic resistance of the substrate, and the contact resistance at the interface of the active material/current collector [Rct) at the electrode/electrolyte interface [Electrochemical impedance spectroscopy is a very significant measure to evaluate the quality of supercapacitors. Figure ollector , changesnterface -36. The nterface ,37-39. A2 composite with improved microstructure.Another critically important factor to evaluate the quality of a supercapacitor is the cycling stability. It is shown in Figure 2 composites have been prepared by a relatively simple microwave sintering method, and a simple method, i.e., dipping Ni-foam into a graphene/MnO2 composite solution directly for a period of time to coat the active material on a current collector, has been proposed for the supercapacitor packaging. It is demonstrated that the microwave reaction time has a significant effect on the microstructure of graphene/MnO2 composites and the electrochemical properties of the supercapacitors based on graphene/MnO2 composites are strongly microstructure dependent. An appropriately longer microwave reaction time, namely, 15 min, facilitates a very dense and homogeneous microstructure of the graphene/MnO2 composites, and thus, excellent electrochemical performance has been achieved in the supercapacitor device based on the graphene/MnO2 composite, comprising a high specific capacitance of 296 F/g and a high capacitance retention of 93% after 3,000 times of charging/discharging cycles. The results obtained in this work pave the way for facile synthesis and optimization of graphene-based composite materials for practical supercapacitor applications.High-quality graphene/MnOThe authors declare that they have no competing interests.XZ designed the study. CZ, ZW, and PS performed the preparation and characterization of materials and supercapacitor devices. YR, JZ (Jiliang), JZ (Jianguo), and DX contributed to the data analysis and discussion. CZ and XZ analyzed the data completely and co-wrote the manuscript. All authors reviewed the manuscript. All authors read and approved the final manuscript.CZ is a postgraduate student at Sichuan University (SCU). XZ has a PhD degree and is a professor at SCU. ZW and PS have a master's degree. YR is a postgraduate student at SCU. JZ (Jiliang) has a PhD degree and is a professor at SCU. JZ (Jianguo) has a PhD degree and is a professor and head of a school at SCU. DX is a professor and head of a research laboratory at SCU.


Radiation induced hardening, evaluated via nanopillar compressions before and after He+ irradiation, is significantly reduced with the inclusion of graphene layers; the flow stresses of V-graphene nanolayers with 110 nm repeat layer spacing showed an increase of 25% while pure V showed an increase of 88% after He+ dosage of 13.5 dpa. The molecular dynamics simulations confirmed that the graphene interface can spontaneously absorb the nearby crystalline defects that are produced from a collision cascade, thereby enhancing the lifetime of the V-graphene nanolayers via this self-healing effect. In addition, the impermeability of He gas through the graphene resulted in suppression of He bubble agglomerations that in turn reduced embrittlement. In-situ SEM compression also showed the ability of graphene to hinder crack propagation that suppressed the failure.Ultra high strength V-graphene nanolayers were developed for the first time that was demonstrated to have an excellent radiation tolerance as revealed by the He Advanced structural material for next generation nuclear facilities require enhanced radiation resistance under harsh irradiation environments to ensure an extended lifetime and therefore the safety of nuclear energy systems24i.e. grain boundary) or heterogeneous (secondary phases) can significantly enhance the radiation tolerance and has been actively researched over the last few decades. One example of using both homogeneous and heterogeneous interfaces in bulk alloys is polycrystalline ferritic/martensitic (F/M) steels with oxide-dispersions (ODS), which is regarded as an effective nuclear structural material due to the ability to absorb crystalline defects at the grain boundaries  as well as the interfaces formed with the oxide phases that are acting as sinks for radiation induced crystalline defects141516Current approaches in enhancing the radiation tolerance include selection of material with reduced scattering cross-section for reduced swelling and engineering of its microstructure to reduce the radiation induced crystalline defects. There are limited metal choices available for nuclear structural applications, and steel is the most widely used material in nuclear facilities. Ni-based alloys are used in applications requiring stability at high temperatures, while Vanadium (V)-based alloys are known to have lower neutron cross section, and reduced radiation induced swelling, and moderate high temperature strength891011et al.22A particularly interesting class of material with enhanced radiation resistance is the metallic nanolayered composite that has been reported to have ultra-high strength181920222325+ irradiation. To further understand the deformation mechanism of V-graphene nanolayers after ion irradiation, in-situ SEM nanopillar compression testing, transmission electron microscopy (TEM) microstructure analysis of the irradiated specimens, and molecular dynamics simulations were performed to understand the enhanced radiation resistance.In our previous work, we reported that graphene with its 2D geometry, outstanding mechanical properties of 130 GPa in strength and Young’s modulus of 1 TPa can be an effective strength enhancer when incorporated in the form of metal-graphene nanolayered composite313334V-graphene nanolayers with 110 nm and 300 nm repeat layer spacings as well as pure V thin film were prepared as outlined in the schematic in The synthesized V-graphene nanolayers with 300 nm repeat layer spacing were analyzed for the initial microstructure using the TEM. Both the micrograph and the selected area diffraction (SAD) shown in + implantation at 120 KeV was used to irradiate pure V, and V-graphene with different repeat layer spacings. The irradiation condition was simulated using Stopping Range of Ions in Material (SRIM)+ ions have sufficient energy to reach down close to the substrate interface (with the penetration depth of ~600 nm on vanadium thin film), thereby fully irradiating the V layers that are to be tested for mechanical properties. The irradiated specimens were analyzed for the presence of crystalline defects and any changes in the microstructure, and detailed cross-sectional TEM image with its SAD patterns with irradiated V-graphene nanolayers with 300 nm repeat layer spacing are shown in 38To analyze the radiation tolerance of V-graphene nanolayers, He+ irradiated pure V and V-graphene nanopillars were then evaluated for radiation induced hardening by comparing the nanopillar compression results before and after the irradiation as shown in et al. for the case of bulk V upon irradiationet al., the He doped bulk V showed hardening of up to twice the original strength and the corresponding brittle failure was reported, where the ductility was reduced from 26% to 4%. For the case of V-graphene nanolayers, however, a significantly smaller degree of embrittlement and radiation induced hardening was observed with the inclusion of graphene, especially with smaller repeat layer spacings or higher density of graphene layers. The radiation induced hardening resulted in increase in flow stress at 5% plastic strain from 4.8 GPa to 6 GPa (25% increase) for the V-graphene with 110 nm repeat layer spacing, from 3.1 GPa to 5.0 GPa (61% increase) for the V-graphene with 300 nm, and from 2.5 GPa to 4.8 GPa (88% increase) for the case of pure V.In the presence of radiation induced defects and He bubble formations, metals can become harder and more brittle, as known as radiation induced hardening. The HeIn-situ SEM nanopillar compression tests were performed for direct observations of the deformation process for irradiated pure V and V-graphene nanolayers with 110 nm repeat layer spacing. For the case of irradiated pure V, brittle failure was observed at 20% strain as shown in As outlined above, He bubble formations are of concern in maintaining the mechanical stability in nuclear structural materials. He is known to rapidly combine with vacancy clusters to form bubbles that can migrate and agglomerate to result in intergranular failure by embrittlement and crck formation4142294445+ irradiation were increased by 40% and 25%, respectively while pure V after irradiation resulted in increase in flow stress of 88%. Significant reduction in radiation hardening in V-graphene nanolayers is expected to be due to reduction in He bubble formation, as well as the ability of the V-graphene interface to absorb the crystalline defects. The total radiation hardening can be expressed asThe increase in yield strength after He implantation is commonly accepted to be due to the formation of radiation induced crystalline defects as well as He bubbles22232447where Radiation induced hardening due to presence of He bubbles  simulations on a model system of pure V and V-graphene nanolayers. We model the radiation event as a collision of a primary knock-on atom (PKA) with 2 keV See . BecauseOne of the main reasons for the reduction in crystalline defects in the presence of the graphene interface is due to the reduction in the vacancy-interstitial formation. The knock-on energy from the collision cascade is typically relaxed through local heating of the crystal lattice as well as by forming vacancy-interstitial pairs, but a large portion of the energy in the case of V-graphene nanolayers is consumed to break the covalent bonds in graphene due to the high atomization energy (7.4 eV) of the graphene. Thus, significant damage of graphene is observed when the knock-on event occurs close to graphene layers see , and thiet al.t) for the vacancy to arrive at the interface asSecond reason for less defect formations is due to the V-graphene interface acting as an efficient sink for the interstitial defects or crowdions. Crowdions move along the [111] directions until they encounter the V-graphene interface, and form adatoms between the graphene and V. Vacancies also diffuse to the V-graphene interface and the arrived vacancies are then trapped at the interface because the vacancy formation energy is smaller at the graphene interface (1.2 eV) than in the bulk lattice (2.5 eV) see . The vac13 Hz, 4 s and 2.43 × 105 s, respectively, at room temperature. However, during the ion irradiation testing and FIB processing to fabricate pillars for compression testing, the actual temperature can increase up to ~200 °C that could then enable vacancies to reach the interface in just a 0.26 seconds for V-graphene with 110 nm repeated layer spacing. Therefore it is expected that the interstitials in the form of crowdion and vacancies gathered at the interface to annihilate near the graphene interfaces. Higher density of the V-graphene interfaces  results in more effective annihilation of interstitials and vacancies, thereby increasing the self-healing ability of the nanolayers. Our analysis is consistent with the experimental observation in which the V-graphene with 110 nm repeat layer spacing showed significantly smaller radiation induced hardening than in 300 nm repeat layer spacing specimen. The self-healing ability as confirmed from MD simulations is expected to be one of the major causes for enhanced radiation tolerance in V-graphene nanolayers, while suppression of He bubbles at the graphene interface also suppress the brittle failure.where + irradiation with dosage of 13.5 dpa revealed that the V-graphene nanolayers had reduced formations of radiation induced crystalline defects compared with pure V, which agreed with the nanopillar compression results of irradiated specimen V-graphene showing reduction in radiation induced hardening and suppression of brittle failure. In-situ SEM compression tests showed that the graphene interface can hinder the crack propagation thus helping to suppress the brittle failure. The structural material degradation due to He bubble formations was shown to be significantly reduced in V-graphene nanolayers due to the impermeability of He through the graphene layer that prevents agglomeration of He gas into large bubbles. Orowan’s model was then used to determine the approximate length scale for the pinning points from the presence of radiation induced defects that indicated less accrual of defects in the V-graphene layers. Finally, MD simulations confirmed that the cause for less crystalline defects in V-graphene layers is due to the graphene interface being able to absorb the crystalline defects that are introduced from collision cascade. Therefore, inclusion of graphene in the form of V-graphene nanolayers can not only result in initially high strength material, but the graphene can self-heal the crystalline defects that are introduced during irradiation as well as terminating migration of He bubbles to result in extremely radiation resistance material.In this study, we developed and analyzed the radiation resistance V-graphene nanolayered composites with varying repeat layer spacings of 110 nm, 300 nm and compared the results to those of pure V. He2 (625 μm/300 nm) substrate was chosen for deposition of the V-graphene nanolayers. Vanadium nanolayers were first deposited using radio frequency (RF) sputtering under vacuum at 5 × 10−6 Torr with Ar gas of 5 mTorr at 10 sccm, and RF power of 200 W was used. After deposition of the V layer, graphene was fabricated by chemical vapor deposition (CVD) and then transferred on to Si/SiO2/V substrate. By repeating the above steps, nanocrystalline V-graphene nanolayers composites were synthesized with 110 nm and 300 nm repeat layer spacings, while keeping the total thickness to be the same at ~600 nm.The Si/SiO−1. The load-displacement data from compression test were analyzed with the conventional constant volume and homogeneous deformation assumption model to calculate the true stress-true strain curvesIn-situ SEM nanopillar compression tests were also conducted to confirm the deformation behavior of the nanopillars using a Hysitron Picoindenter (PI-95) in a Quanta 3D FEG FIB. Same sized nanopillars were compressed under in-situ SEM at a nominal constant strain rate of 0.002 s−1.To test the mechanical properties of the V-graphene nanolayers composites, the Quanta 3D FEG Focused ion beam (FIB) milling was utilized to fabricate V-graphene nanopillars with diameter of 250 nm and height of 600 nm. The pillar compression tests were performed by the Hysitron Tbi-750  nanoindentation system with a 10 μm diameter flat-ended cube corner tip. All pillars were compressed over 15% total strain in a displacement control feedback mode (DC mode) using the Hysitron quasi-static indentation transducer with nominal engineering strain rate of 0.002 s+ ion irradiation was performed at Kyungjoo Korea Multi-Purpose Accelerator Complex (KAERI) facility at 120 keV with beam current of 1.2 mA and dosage of 1 × 1018/cm2 at room temperature. The SRIM calculations indicate (state the simulation conditions and assumptions) that this irradiation condition is sufficient to reach through thickness of the V layers down close to the substrate interface. The benefits of ion irradiation in probing the radiation resistance of materials rather than using neutron irradiations were previously reported in the work by Kiener et al.To evaluate the radiation resistance of V-graphene nanolayers, HeHow to cite this article: Kim, Y. et al. Radiation Resistant Vanadium-Graphene Nanolayered Composite. Sci. Rep.6, 24785; doi: 10.1038/srep24785 (2016).