Transplantation of stem cells from human exfoliated deciduous teeth for bone regeneration in the dog mandibular defect

AIM: To investigate the effect of stem cells from human exfoliated deciduous teeth(SHED) transplanted for bone regeneration in the dog mandibular defect.METHODS: In this prospective comparative study, SHEDs had been isolated 5 years ago from human exfoliated deciduous teeth. The undifferentiated stem cells were seeded into mandibular bone through-andthrough defects of 4 dogs. Similar defects in control group were filled with cell-free collagen scaffold. After 12 wk, biopsies were taken and morphometric analysis was performed. The percentage of new bone formation and foreign body reaction were measured in each case. The data were subject to statistical analysis using the Mann-Whitney U and Kruskalwalis statistical tests. Differences at P < 0.05 was considered as significant level.RESULTS: There were no significant differences between control and SHED-seeded groups in connective tissue(P = 0.248), woven bone(P = 0.248) and compact bone(P = 0.082). There were not any side effects in transplanted SHED group such as teratoma or malignancy and abnormalities in this period.CONCLUSION: SHEDs which had been isolated and characterized 5 years ago and stored with cryopreservation banking were capable of proliferation and osteogenesis after 5 years, and no immune response was observed after three months of seeded SHEDs.

Electrochemically exfoliated graphene as high-performance catalyst support to promote electrocatalytic oxidation of methanol on Pt catalysts

Electrochemically exfoliated graphene(EEG)is a kind of high-quality graphene with few oxygen-containing functional groups and defects on the surface,and thereby is more suitable as catalyst support than other carbon materials such as extensively used reduced graphene oxide(rGO).However,it is difficult to grow functional materials on EEG due to its inert surface.In this work,ultra-small Pt nanocrystals(~2.6 nm)are successfully formed on EEG and show better electrocatalytic activity towards methanol oxidation than Pt catalysts on r GO.The outstanding catalytic properties of Pt catalysts on EEG can be attributed to the fast electron transfer through EEG and high quality of Pt catalysts such as small grain size,high dispersibility and low oxidation ratio.In addition,SnO2 nanocrystals are controllably generated around Pt catalysts on EEG to raise the poison tolerance of Pt catalysts through using glycine as a linker.Owing to its outstanding properties such as high electrical conductivity and mechanical strength,EEG is expected to be widely used as a novel support for catalysts.

Absorption and Photocataly tic Degradation of Machine Oil by Exfoliated Graphite-Supported Nanometer TiO2 Material

By loading nanometer anatase onto exfoliated graphite with the sol-gel method, exfoliated graphite-TiO2 composite （EG-TiO2） can be prepared, which can adsorb oil and can also degrade oil. In a technologic condition for preparing EG-TiO2, the impregnated number of times is the most important factor to influence oil-adsorbing capability, that is, when the impregnated number of times increases, the amount of saturation-adsorbed oil decreases. The study of EG-TiO2 photocatalytic degradation of machine oil based on the weight-loss method and infrared spectrum method indicates that EG-TiO2 has obvious effect of photocatalytic degradation for machine oil. Its performance is superior to pure nanometer TiO2 powder because nanometer TiO2 in EG-TiO2 has three-dimension laminar structure and comparatively high adsorption capability.

Stem cells from human exfoliated deciduous teeth ameliorate concanavalin A-induced autoimmune hepatitis by protecting hepatocytes from apoptosis

BACKGROUND Autoimmune hepatitis is a serious autoimmune liver disease that threatens human health worldwide,which emphasizes the urgent need to identify novel treatments.Stem cells from human exfoliated deciduous teeth(SHED),which are easy to obtain in a non-invasive manner,show pronounced proliferative and immunomodulatory capacities.AIM To investigate the protective effects of SHED on concanavalin A(ConA)-induced hepatitis in mice,and to elucidate the associated regulatory mechanisms.METHODS We used a ConA-induced acute hepatitis mouse model and an in vitro co-culture system to study the protective effects of SHED on ConA-induced autoimmune hepatitis,as well as the associated underlying mechanisms.RESULTS SHED infusion could prevent aberrant histopathological liver architecture caused by ConA-induced infiltration of CD3+,CD4+,tumor necrosis-alpha+,and interferon-gamma+inflammatory cells.Alanine aminotransferase and aspartate aminotransferase were significantly elevated in hepatitis mice.SHED infusion could therefore block ConA-induced alanine aminotransferase and aspartate aminotransferase elevations.Mechanistically,ConA upregulated tumor necrosisalpha and interferon-gamma expression,which was activated by the nuclear factor-kappa B pathway to induce hepatocyte apoptosis,resulting in acute liver injury.SHED administration protected hepatocytes from ConA-induced apoptosis.CONCLUSION SHED alleviates ConA-induced acute liver injury via inhibition of hepatocyte apoptosis mediated by the nuclear factor-kappa B pathway.Our findings could provide a potential treatment strategy for hepatitis.

Sorption Behaviours of Exfoliated Graphite

Exfoliated graphite (EG) is selected as a new kind of sorbent to sorb heavy oil spilled. In order to make use of EG more effectively, some basic experiments are performed to investigate its sorption properties, i.e. , specific sorption, height of saturation layer, sorption time constant. In the present experiments, A grade heavy oil is employed as a standard sorbate. It is concluded that 1) under the condition that the area of solid (filter bottom) liquid (heavy oil) interface is a constant, specific sorption usually decreases when the amount of EG filled or the apparent bulk density increase; however, the specific sorption initially increases when the apparent bulk density is too low and the amount of EG filled is too much; 2) under the condition that the apparent bulk density of EG filled is a constant, the sorption time constant tends to increase when the amount of EG filled increases; however, for a constant amount of EG filled, the sorption time constant will decrease when the apparent bulk density increases.

Synthesis and Characterization of Exfoliated Graphite/ABS Composites

Exfoliated graphite was prepared by chemical route and then further subjected to thermal oxidation and sonication for size reduction and increased interlayer spacing in natural flake graphite. Exfoliated graphite/ABS composites were pre-pared with varying filler concentration by solution casting method. Exfoliated graphite and composites were character-ised by scanning electron microscopy and energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and X-ray diffractometry techniques. After thermal exfoliation significant peak of graphite at 2? = 26.4? disappeared completely, confirming successful exfoliation of graphite. SEM images revealed homogeneous dispersion of exfoliated graphite in the matrix and EDAX confirmed successful reduction of graphite oxide.

High-Density Polyethylene Based on Exfoliated Graphite Nanoplatelets/Nano-Magnesium Oxide: An Investigation of Thermal Properties and Morphology

In this study, high-density polyethylene (HDPE)/exfoliated graphite nanoplatelet (xGnP) composites reinforced with a 2 wt.% concentration of nano-magnesia (n-MgO) were fabricated using an injection moulding machine. The thermal properties and morphological structures of the composites were investigated. The XRD results showed the peaks of xGnP and n-MgO, where the intensity of the xGnP peaks became stronger with adding increasing amounts of xGnP into the polymermatrix. In terms of morphology, some agglomeration of particles was observed within the matrix, and the agglomeration decreased the thermal properties of the composites. The nanocomposites showed less thermal stability than the pristine polymer. The reduction in the onset temperature compared to that of neat HDPE was attributed to less adhesion between the fillers and the matrix. In addition, the crystallinity was reduced by the addition of fillers.

Development of Cu-Exfoliated Graphite Nanoplatelets (xGnP) Metal Matrix Composite by Powder Metallurgy Route

In the present investigation the possibility of using exfoliated graphite nanoplatelets (xGnP) as reinforcement in order to enhance the mechanical properties of Cu-based metal matrix composites is explored. Cu-based metal matrix composites reinforced with different amounts of xGnP were fabricated by powder metallurgy route. The microstructure, sliding wear behaviour and mechanical properties of the Cu-xGnP composites were investigated. xGnP has been synthesized from the graphite intercalation compounds (GIC) through rapid evaporation of the intercalant at an elevated temperature. The thermally exfoliated graphite was later sonicated for a period of 5 h in acetone in order to achieve further exfoliation. The xGnP synthesized was characterized using SEM, HRTEM, X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy. The Cu and xGnP powder mixtures were consolidated under a load of 565 MPa followed by sintering at 850°C for 2 h in inert atmosphere. Cu-1, 2, 3 and 5 wt% xGnP composites were developed. Results of the wear test show that there is a significant improvement in the wear resistance of the composites up to addition of 2 wt% of xGnP. Hardness, tensile strength and strain at failure of the various Cu-xGnP composites also show improvement upto the addition of 2 wt% xGnP beyond which there is a decrease in these properties. The density of the composites decreases with the addition of higher wt% of xGnP although addition of higher wt% of xGnP leads to higher sinterability and densification of the composites, resulting in higher relative density values. The nature of fracture in the pure Cu as well as the various Cu-xGnP composites was found to be ductile. Nanoplatelets of graphite were found firmly embedded in the Cu matrix in case of Cu-xGnP composites containing low wt% of xGnP.

Hydrothermal exfoliated molybdenum disulfide nanosheets as anode material for lithium ion batteries

Ultrathin MoS2 nanosheets were prepared in high yield using a facile and effective hydrothermal intercalation and exfoliation route. The products were characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the high yield of MoS2 nanosheets with good quality was successfully achieved and the dimensions of the immense nanosheets reached 1 μm-2/zm. As anode material for Li-ion batteries, the as-prepared MoS2 nanosheets electrodes exhibited a good initial capacity of 1190 mAh.g-l and excellent cyclic stability at constant current density of 50 mA.g-1. After 50 cycles, it still delivered reversibly sustained high capacities of 750 mAh.g-1.

Preparation of Exfoliated Low-density Polyethylene/Montmorillonite Nanocomposites Through Melt Extrusion

The effects of ethylene vinyl acetate copelymer （EVA） as a compatibilizer on the dispersion of organically modified montmorillonite（org-MMT） into low-density polyethylene（LDPE） during melt extrusion compounding were studied. The X-ray diffraction patterns reveal that as compared with LDPE, EVA can intercalate more easily into the interlay gallery of org-MMT when the composites contain a low org-MMT content. Exfoliated LDPE/org-MMT nanocompesites in the presence of an EVA compatibilizer could be prepared by using a two-step melt compounding technique with a twin-screw extruder.

Functionalized Exfoliated Graphene Oxide as Supercapacitor Electrodes

Functionalized exfoliated graphene oxide (EGO) for supercapacitor electrodes have been synthesized by simple chemical methods from the exfoliated graphite (EG) as precursor. Structural and morphological characterizations of EGO have been carried out using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), FTIR and Raman spectroscopy. Electrochemical performance of these electrodes has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The fabricated supercapacitor gave a specific capacitance of 146 Fg-1 and energy density of 20 Wh·kg-1 for a highly oxidized sample with more functional groups compared to pure, lower level oxidized and reduced samples. The single and multi layered graphene oxide sheets produced by this method have a lower degree of agglomeration. We found that the graphene oxide with functional oxygen groups of quinine type enhances the capacitance compared to other oxygen functional groups.

Exfoliated multi-layered graphene anode with the broadened delithiation voltage plateau below 0.5 V

The commercial graphite(CG)is the conventional anode material for lithium ion batteries(LIBs)due to its low delithiation voltage plateau(below 0.5 V)and extraordinary durability.Nevertheless,the further promotion of energy density of LIBs is restricted by the limited capacity below 0.5 V of CG.Here,based on the supercritical CO2 exfoliation technique,the production of multi-layered graphene(MLG)is achieved from the pilot scale production line.The great merit of the exfoliated MLG anode is that the voltage plateau below 0.5 V is broadened obviously as compared to those of natural graphite and CG.Additionally,no obvious lithium dendrites are observed for MLG during the lithiation process.The large delithiation capacity under the low voltage plateau of MLG is mainly benefited from the combination of Li intercalation and boundary storage mechanism,which is further confirmed by the density functional theory calculations.The LiFePO4/MLG full cell can afford the satisfactory electrochemical property with respect to the capacity,energy density and ultralong cycling stability(90%capacity retention after 500 cycles at 2 C),significantly better than that of LiFePO4/CG.Besides,this developed technique not only dedicates to producing the high-performance anode for LIBs but also opens a door for the mass production of MLG in the industrial scale.

Analysis of Human Papillomavirus Infection in Cervical Exfoliated Cells

To screen patients with early cervical lesions by analyzing the infection of high-risk Human papillomavirus (HR-HPV). Research Methods: The cervical exfoliated cell specimens and their clinical data were collected. The HPV infection types of the collected specimens were detected by fluorescence quantitative PCR, and the correlation between HPV infection and clinicopathological features was analyzed statistically. Results: 725 cases were HR-HPV positive from 2605 cases, including 15 high-risk types of HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68. Different histological types ranged from NILM to HSIL, and the positive rate of HPV showed an increasing trend with the aggravation of cervical lesions. Conclusion: The positive rate of 15 high-risk HPV types in the collected specimens was 27.8%. Patients with early cervical lesions could be screened for 15 high-risk HPV infection types.

Graphene Oxide/Multilayer-Graphene Synthesized from Electrochemically Exfoliated Graphite and Its Influence on Mechanical Behavior of Polyurethane Composites

Graphene Oxide/Multilayer-Graphene (GO-MG) flakes were obtained using an electrochemically exfoliated graphite (GR) electrode from secondary steel-making industry performed in a two-electrode system using tungsten as the counter electrode and GR as the working electrode. The exfoliated GO-MG flakes were processed and incorporated in an elastomeric polyurethane (PU) matrix. The mechanical properties of the PU/GO-MG composites were evaluated and compared with equivalent composites made of PU/GR powder. From experimental data analysis it was concluded that GO-MG flakes were approximately composed of 67 wt% GO and 33 wt% MG. The number of layers in the graphene flakes was estimated to be between 2 and 5 sheets. PU showed a breaking stress of 570 kPa, while the PU/20wt% GR attained a maximum stress of 750 kPa as compared to PU/10wt% GO-MF composite exhibiting a breaking stress of 1060 kPa.

High-temperature resistant polymer nanocomposites with exfoliated organic-modified montmorillonite nanosheets strongly adsorbed on polymer chains

It has been demonstrated that almost all polymer-clay nanocomposites show higher temperature stability than that of pure polymer, which is attributed to the active exfoliated clay nanosheet firmly adsorbed onto the polymer chains, due to polerization and nucleation effect, the clay nanosheets could protect the polymer chains from destroying. To prove such mechanism, the water-soluble polymer nanocomposites(AAA/SLS-MMT) were synthesized by the in-situ polymerization of 2-acrylamide-2-methyl-propane sulfonic acid, acrylamide, 4-acryloylmorpholine, and organically modified montmorillonite. The techniques of nuclear magnetic resonance, atomic force microscopy and scanning electron microscopy etc., clearly characterized the successful synthesized of sample's structure, the exfoliated MMT nanosheet adsorbed polymer chain's scale, and well-dispersed morphology, espectively. The adsorption model, X-ray photoelectron spectroscopy presented the existence of strong adsorption, while molecular simulation calculations first concluded that the strong adsorption energy was-13032.06 kcal/mol. Thermo-gravimetric-analysis proved the temperature of maximum thermal degradation of powder sample(AAA/1.0 wt% SLS-MMT) was over 298℃. After ageing at 180℃ for 4 h, the apparent viscosity of 5 g/L AAA/1.0 wt% SLS-MMT aqueous solution was 326.7 mPa,s, while that of pure polymer(AAA) was only 8.3 mPa,s. This optimized sample has the smallest FLAPIvalue at all test temperatures from 180 to 220℃ in both fresh and salt water based drilling fluid. All the evidences of high temperature resistance indicate that the strong adsorption can enhance the thickness of hydrated shell and adsorption of clay particles in drilling fluid at high temperature. Such mechanism supplied the better way to design high-temperature resistant fluid loss additives for deep and ultra-deep oil and gas formation engineering.

A facile strategy for large-scale production of 2D nanosheets exfoliated by three-roll milling

Two-dimensional(2D)nanomaterials,such as graphene,MoS_(2),and MAX,have attracted increasing research attention in recent years due to their unique structural and performance advantages.However,their complex production processes and equipment requirements are significant issues affecting their widespread use.Here,with an exfoliation strategy using three-roll milling,we present a simple,cost-effective,and extensible method to produce multilayer graphene,BN,MoS_(2),and Ti_(3)AlC_(2) nanosheets.The roller and phenolic resin created three kinds of forces on the layered 2D materials,i.e.,shear forces,compressive forces,and adhesive forces,which exfoliated layered materials from their edges and surfaces into nanosheets.Subsequently,the exfoliated materials were ultrasonically washed with alcohol,treated with ultrasonic vibration,and centrifuged to obtain 2D nanomaterials.The easy operation and high yield are attractive for research based on the construction of high-performance 2D nanosheet-based devices at low cost.Herein,the obtained multilayer graphene and MoS_(2) nanosheets were used as anode materials of sodium/potassium-ion batteries,respectively,to test their electrochemical properties.Better performances are obtained compared with their primary bulk materials.

3D printing of high-performance micro-supercapacitors with patterned exfoliated graphene/carbon nanotube/silver nanowire electrodes

Micro-supercapacitors(MSCs)show great potential as on-chip energy storage devices for portable electronics.The major flaw of thin-film MSCs is their low energy density.To improve the energy density,thicker electrodes are required.However,the fabrication of MSCs with thick electrodes remains a challenge.In this work,a novel 3D printing method is employed to fabricate high-performance MSCs with interdigitated exfoliated graphene(EG)/carbon nanotube(CNT)/silver nanowire(Ag NW)electrodes.The nanowelding of Ag NW junction plays a critical role in the realization of 3D printing.To enhance the electrochemical performances of EG,phosphorus atoms are incorporated into the carbon framework with 1.7 at%.The areal capacitance of the 3D printed MSC is 21.6 mF cm^(-2)at a scan rate of 0.01 V s^(-1).The areal energy density of the MSC ranges from 0.5 to 2μWh cm^(-2)with a maximum power density of 2.5 mW cm^(-2).

Mechanically exfoliated MoS_(2) nanosheets decorated with SnS_(2) nanoparticles for high-stability gas sensors at room temperature

Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing properties of pure MoS_(2) nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen,which results in weak stability for MoS_(2)-based gas sensors.Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS_(2) nanosheets.In this work,we design a novel nanocomposite based on MoS_(2) nanosheets decorated with tin disulfide(SnS_(2))nanoparticles(MoS_(2)/SnS_(2))via combining the mechanical exfoliation method with the facile hydrothermal method.The experimental results indicate that,after surfaces decoration with SnS_(2) nanoparticles,the as-prepared gas sensor based on MoS_(2)/SnS_(2) nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3%at room temperature.Moreover,the MoS_(2)/SnS_(2) sensor also possesses desirable gas sensing properties upon NO_(2) at room temperature,such as high sensitivity,rapid response/recovery speed(28 s/3 s,5×10^(-6) NO_(2)),satisfactory selectivity,favorable repeatability and reversibility.The improved gas sensing properties of MoS_(2)/SnS_(2) nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS_(2) nanoparticles.This work elucidates that SnS_(2) nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS_(2) nanosheets,providing a promising approach to achieve high-stability NO2 gas sensors at room temperature.

Preparation and Characterization of Exfoliated Poly（ethyleneterephthalate）/Montmorillonite Nanocomposites Using Modified MMTs with Variable Content of Antimony Acetate

Poly（ethylene terephthalate） （PET）/montmorillonite （MMT） nanocomposite was prepared by the direct polymerization with MMTs modified with variable content of antimony acetate （Sb（OAc）3）, which was also used as catalyst polymerization. The modified MMTs （AS-Sb-MMT） were prepared by intercalating both Sb（OAc）3 and amphoteric surfactant （AS） into MMT layers. Nine kinds of Sb-MMTs [MMT treated with Sb（OAc）3] with different Sb content were obtained, but only six kinds of PET/MMT nanocomposites could be prepared. ICPAES was used to characterize Sb content of modified MMT, XRD was used to characterize interlayer spacing, IR spectroscopy was used to characterize composition change of Sb catalyst in modified MMT and TEM was used to investigate micromorphology of PET/MMT nanocomposites. Several results are obtained, i.e., （a） Sb content of Sb-MMT is affected by both drying temperature and washing-drying sequence, （b） compared with Na-MMT （unmodified MMT）, the change in the interlayer spacing of Sb-MMT is attributed to the solvent ethylene glycol （EG） rather than the intercalated or absorbed Sb（OAc）3, （c） based on this, a model is developed to describe the swelling of Na-MMT and modified MMT by EG and the effect of drying temperature on the interlayer spacing, （d） exfoliation state of MMT in PET matrix of nanocomposites is controlled not only by Sb content and interlayer spacing, but also by the composition of Sb catalyst in modified MMT.

Fast response speed of mechanically exfoliated MoS2 modified by PbS in detecting NO2

MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such as poor sensitivity,long response time.Constructing the hete ro structure is an effective approach to improve gas-sensing performance of MoS2.Herein,PbS@MoS2 composites synthesized by mechanical exfoliation combining with wet-chemical precipitation are used to investigate its performance in detecting NO2 at room temperature.The response value of PbS@MoS2 gas sensor against NO2 is significantly improved compared with the pure MoS2 gas sensor.At the same time,the modification with PbS also accelerates the response speed of MoS2,and the response time is almost reduced by two orders of magnitude,from hundreds of seconds to less than ten seconds.The enhanced response value and fast response time are mainly benefited from the modulation effect of NO2 to PbS@MoS2 heterostructure and the mechanically exfoliated MoS2 surface with few defects.This work can be expected to provide useful guidance for designing composite materials with excellent gas sensing properties.