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Nitrogen doped graphene supported TiO2 hollow nanostructures varying from 10 to 15 nm were designed for sodium ion battery anode applications, which were obtained by a two-step technique hydrothermal-calcining process with urea as an inhibitor and a nitrogen source. The active nitrogen modified graphene matrix supported hollow hierarchical-pore nanoarchitectures, possessing high surface area, massive pores including micro-, meso- and macro-pores, and excellent structural stability, which are highly desirable for application in sodium ion batteries. Its interconnected carbon network ensures good conductivity and fast electron transport; the micro-, meso-, and macroporous nature effectively shortens the sodium ion diffusion path and provides the room necessary for volume expansion. The large specific surface area is beneficial for better contact between the electrode materials and the electrolyte. Such material exhibits excellent performance as anode materials for sodium ion batteries with a high reversible capacity, excellent cycle stability and superior rate capability. Besides, nitrogen and graphene play a crucial role in controlling the formation of the TiO2 hollow nanocrystals.

Three dimensional (3D) porous C/LiFePO 4 /MWCNTs was synthesized by a hybrid of in situ sol gel strategy and a facile electro-polymerization polyaniline technique and a simultaneous sintering progress. In combined with the 3D hierarchical pore topologies and high electronic conduction facilitating the kinetics of both electron transport and lithium ion diffusion within the particles, the optimized electrodes exhibit an ultrahigh rate capacity, stable charge/discharge cycle ability, and a comparative volume capacity. The synthesized LiFePO 4 composite offers a discharge capacity of 169.6mAhg −1 (nearly to its the theoretical capability 170mAhg −1 ) at the C/10 rate and delivers a good rate performance with a capacity of 141.9mAh g −1 at a high rate of 20 C, and stable charge/discharge cycle ability (>95% capacity retention after 200 charge/discharge cycles).This non-organic facile synthesize avenue can be high desirable to prepare high-power electrode materials

Low temperature, 300–600 °C solid oxide fuel cell (LTSOFC) is one of the hot areas in recent fuel cell development. In order to develop high performance LTSOFCs, compatible electrodes are highly demanded. In this work, a lithium transition metal oxide electrode material with hierarchical porous structure was synthesized. The phase structure was analysed by XRD and microstructure was studied by SEM. The as-synthesized material was constructed to devices using the SDC (samarium doped ceria)-carbonate nanocomposite (NSDC) as the electrolyte to test the OCV (open circuit voltage), which indicates good catalytic performance for H2 at 600 °C.

Double-shelled MnO 2 hollow spheres were prepared through a self-template route, by the double oxidation-dissolution rounds of the MnCO 3 precursors. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), field emission scanning microscopy (FESEM) and transmission electron microscopy (TEM) together record the composition and structure evolution during the entire process. The multilayer hollow spheres contain a central hollow interior and a clear gap between the outer and inner shells. Such hollow MnO 2 nanoparticles have great potential in energy storage and conversion, showing a high specific capacitance of 210.2 F g −1 at 0.2 A g −1 and an attractive capacity retention ratio of 86.2% when current density increases 25 times to 5 A g −1 .

Behaviors of atomic defects in graphene sheets in air at high temperature are studied. Results indicate that the number of defects in graphene sheets decreases after high temperature treatment in air. Mechanism for the behaviors are studied by molecular simulations and interpreted as follows. Charge distributions of atoms in graphene sheets are relatively uniform due to large conjugated π bond, but atomic defects in the graphene sheets change the uniform charge distributions. The change of charge distributions makes these defect-regions have higher chemical activities, thus these defect-regions are easy to be eroded selectively by O 2 in air, which makes the number of them decrease. Thus, high temperature treatment in air can be used as a novel method to control atomic defects in graphene sheets. However, in order to obtain the graphene sheets after reactions, two problems should be dealt with: one is sufficient contact between air and graphene sheets during reaction; the other is transfer and enrichment of graphene sheets after reaction. Our method dealt with the two problems.

The alteration of p21-activated kinase 4 (PAK4) and transforming growth factor-beta (TGF-β) signaling effector Smad2/3 was detected in several types of tumors, which acts as oncogenic factor and tumor suppressor, but the relationship between these events has not been explored. Here, we demonstrate that PAK4 interacts with and modulates phosphorylation of Smad2/3 via both kinase-dependent and kinase-independent mechanisms, which attenuate Smad2/3 axis transactivation and TGF-β-mediated growth inhibition in gastric cancer cells. First, PAK4 interaction with Smad2/3, which is independent of PAK4 kinase activity, blocks TGF-β1-induced phosphorylation of Smad2 Ser465/467 or Smad3 Ser423/425 and the consequent activation. In addition, PAK4 phosphorylates Smad2 on Ser465, leading to the degradation of Smad2 through ubiquitin-proteasome-dependent pathway under hepatocyte growth factor (HGF) stimulation. Interestingly, PAK4 expression correlates negatively with phospho-Ser465/467 Smad2 but positively with phospho-Ser465 Smad2 in gastric cancer tissues. Furthermore, the expressions of HGF, phospho-Ser474 PAK4 and phospho-Ser465 Smad2 are markedly increased in gastric cancer tissues, and the expression of Smad2 is decreased in gastric cancer tissues. Our results document an oncogenic role of PAK4 in repression of Smad2/3 transactivation that involved in tumorigenesis, and suggest PAK4 as a potential therapeutic target for gastric cancer.

Mesoporous carbons were synthesized using thermoplastic phenolic resin (PF) as carbonaceous precursor and magnesium citrate as template precursor. Pore structure was determined as ink-bottle-like geometry through TEM, N2 adsorption analysis combined with TG curves. The porous carbons prepared were then applied as electrode material for electric double-layer capacitors. The capacitor performance was examined in 30 wt% KOH aqueous solution by cyclic voltammetry and galvanostatic charge/discharge measurements. The carbon prepared with MgO/PF mass ratio of 8/2 had a BET surface area of 1920 m2 g−1 and exhibited a capacitance of 220 F g−1 at a current density of 50 mA g−1. Besides, the carbon with the ratio of 4/6 had the optimize proportion of mesopores, which ensures its good rate performance that up to 98.3%, expressed as the ratio of the capacitance measured at 1000 mA g−1 against that at 50 mA g−1.

Lithium-ion capacitors (LICs) were fabricated using mesocarbon microbeads (MCMB) as a negative electrode and a mixture of activated carbon (AC) and LiFePO4 as a positive electrode (abbreviated as LAC). The phase structure and morphology of LAC samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The electrochemical performance of the LICs was studied using cyclic voltammetry, charge-discharge rate measurements, and cycle performance testing. A LIC with 30 wt% LiFePO4 was found to have the best electrochemical performance with a specific energy density of 69.02 W h kg−1 remaining at 4 C rate after 100 cycles. Compared with an AC-only positive electrode system, the ratio of practical capacity to theoretical calculated capacity of the LICs was enhanced from 42.22% to 56.59%. It was proved that adding LiFePO4 to AC electrodes not only increased the capacity of the positive electrode, but also improved the electrochemical performances of the whole LICs via Li+ pre-doping.

The traditional techniques for preparing spinnable pitch from coal tar pitch are air blowing or thermal treatment. A new method to produce isotropic spinnable pitch has been developed. In this method, a commercial almost free of quinoline insoluble (almost QI-free) coal tar pitch was firstly air blown in the temperature range of 280 to 320 °C. Air blowing increases the softening point of the pitch without destroying its spinnability. Next, a thermal treatment between 350 and 380 °C was applied and this increased the softening point to 280 °C. The effects of processing parameters such as treatment time and temperature for air blowing and thermal treatment on the characteristics of the spinnable pitch were studied. The spinnable pitch obtained by the two-step technique exhibited a high softening point (280 °C), a high coking value (82%). The green fibers spun from the pitch, showed uniform diameters (19 ± 1 μm) with smooth and homogeneous surfaces. The green fibers were then stabilized at 320 °C for 1 h and further carbonized at 1000 °C for 1 h in nitrogen. The obtained carbon fibers also had smooth surfaces and homogeneous diameters (17 ± 1 μm).

Pr2NiO4-Ag composite was synthesized and evaluated as cathode component for low temperature solid oxide fuel cells based on ceria-carbonate composite electrolyte. X-ray diffraction analysis reveals ...

The solid oxide fuel cell (SOFC) is a potential high efficient electrochemical device for vehicles, auxiliary power units and large-scale stationary power plants combined heat and power application. The main challenges of this technology for market acceptance are associated with cost and lifetime due to the high temperature (700-1000 oC) operation and complex cell structure, i.e. the conventional membrane electrode assemblies. Therefore, it has become a top R&D goal to develop SOFCs for lower temperatures, preferably below 600 oC. To address those above problems, within the framework of this thesis, two kinds of innovative approaches are adopted. One is developing functional composite materials with desirable electrical properties at the reduced temperature, which results of the research on ceria-based composite based low temperature ceramic fuel cell (LTCFC). The other one is discovering novel energy conversion technology - Single-component/ electrolyte-free fuel cell (EFFC), in which the electrolyte layer of conventional SOFC is physically removed while this device still exhibits the fuel cell function. Thus, the focus of this thesis is then put on the characterization of materials physical and electrochemical properties for those advanced energy conversion applications. The major scientific content and contribution to this challenging field are divided into four aspects except the Introduction, Experiments and Conclusions parts. They are:Continuous developments and optimizations of advanced electrolyte materials, ceria-carbonate composite, for LTCFC. An electrolysis study has been carried out on ceria-carbonate composite based LTCFC with cheap Ni-based electrodes. Both oxygen ion and proton conductance in electrolysis mode are observed. High current outputs have been achieved at the given electrolysis voltage below 600 oC. This study also provides alternative manner for high efficient hydrogen production. Compatible and high active electrode development for ceria-carbonate composite electrolyte based LTCFC. A symmetrical fuel cell configuration is intentionally employed. The electro-catalytic activities of novel symmetrical transition metal oxide composite electrode toward hydrogen oxidation reaction and oxygen reduction reaction have been experimentally investigated. In addition, the origin of high activity of transition metal oxide composite electrode is studied, which is believed to relate to the hydration effect of the composite oxide.A novel all-nanocomposite fuel cell (ANFC) concept proposal and feasibility demonstration. The ANFC is successfully constructed by Ni/Fe-SDC anode, SDC-carbonate electrolyte and lithiated NiO/ZnO cathode at an extremely low in-situ sintering temperature, 600 oC. The ANFC manifests excellent fuel cell performance (over 550 mWcm-2 at 600 oC) and a good short-term operation as well as thermo-cycling stability. All results demonstrated its feasibility and potential for energy conversion.Fundamental study results on breakthrough research Single-Component/Electrolyte-Free Fuel Cell (EFFC) based on above nanocomposite materials (ion and semi-conductive composite) research activities. This is also the key innovation point of this thesis. Compared with classic three-layer fuel cells, EFFC with an electrolyte layer shows a much simpler but more efficient way for energy conversion. The physical-electrical properties of composite, the effects of cell configuration and parameters on cell performance, materials composition and cell fabrication process optimization, micro electrochemical reaction process and possible working principle were systematically investigated and discussed. Besides, the EFFC, joining solar cell and fuel cell working principle, is suggested to provide a research platform for integrating multi-energy-related device and technology application, such as fuel cell, electrolysis, solar cell and micro-reactor etc.This thesis provides a new methodology for materials and system innovation for the fuel cell community, which is expected to accelerate the wide implementation of this high efficient and green fuel cell technology and open new horizons for other related research fields.

Carbon coating of fine particles of Li 4 Ti 5 O 12 synthesized under hydrothermal condition is carried out by amphiphilic carbonaceous material (ACM) in aqueous solution, followed by carbonization at 800 °C for 2 h. The particles prepared are comprised of highly-crystalline spinel-type Li 4 Ti 5 O 12 with the size in the range of 100–400 nm without any agglomeration, of which surface is uniformly covered by a thin carbon layer. Their electrochemical performance as an anode in lithium-ion batteries is evaluated. The initial discharge capacity of carbon-coated Li 4 Ti 5 O 12 at 20 C rate is 137 mA h g −1 and remains as high as 125 mA h g −1 after 100 cycles (91% retention), exhibiting good rate and cyclic performance. Carbon coating by using ACM as carbon precursor gives the Li 4 Ti 5 O 12 particles an enhanced performance as an anode in lithium-ion batteries, owing to the improvement in electrical conductivity, polarization and ability of dispersion. This non-organic coating process may present a new economic, facile, and green pathway for the preparation of carbon-coated Li 4 Ti 5 O 12 as a high power anode material in lithium-ion batteries.

The shift to low operational temperature of solid oxide or ceramic fuel cells has induced many new concepts and novel technologies. In the present study, fuel cell assembled by all nano composite materials – NiO/Fe 2 O 3 -SDC anode, SDC-carbonate electrolyte and lithiated NiO/ZnO cathode – is investigated. A range of techniques, i.e., X-ray diffraction (XRD), Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy as well as polarization measurements are employed to characterize the crystalline structures, morphologies and electrochemical properties of the synthesized nanocomposite materials and cells. Performance comparison is made between single cells with and without a pre-sintering process. Finally, single cell short term stability and thermo cycle behaviors are also examined. Combined the facile fabrication process, relative high performance and reasonable stability, the current all nanocomposite system may be a promising functional system for low temperature ceramic fuel cells.

A three-dimensional nanostructure composed of birnessite MnO 2 and carbon black (CB) was built via a quite simple co-precipitation method at room temperature. The natural porous construction of conductive CB granules provided enough sites for MnO 2 deposition. The as-prepared composite showed that dispersive MnO 2 nanowires were directly crystallized on the surface of CB matrix, which was believed to be beneficial to its electrochemical performance. The further investigation of cyclic voltammetry (CV) in 1 M Na 2 SO 4 confirmed the inference, which showed good symmetrical rectangular shape, and the specific capacitance was calculated about 186 F/g at a scan rate of 2 mV/s. After 1000 cycles of CV at 10 mV/s, the initial capacitance was maintained at about 91%, indicating that the designed structure had benefit to high electrochemical stability.

Histone modifications play important roles in regulating eukaryotic gene expression and have been used to model expression levels. Here, we present a regression model to systematically infer mRNA stability by comparing transcriptome profiles with ChIP-seq of H3K4me3, H3K27me3 and H3K36me3. The results from multiple human and mouse cell lines show that the inferred unstable mRNAs have significantly longer 3′Untranslated Regions (UTRs) and more microRNA binding sites within 3′UTR than the inferred stable mRNAs. Regression residuals derived from RNA-seq, but not from GRO-seq, are highly correlated with the half-lives measured by pulse-labeling experiments, supporting the rationale of our inference. Whereas, the functions enriched in the inferred stable and unstable mRNAs are consistent with those from pulse-labeling experiments, we found the unstable mRNAs have higher cell-type specificity under functional constraint. We conclude that the systematical use of histone modifications can differentiate non-expressed mRNAs from unstable mRNAs, and distinguish stable mRNAs from highly expressed ones. In summary, we represent the first computational model of mRNA stability inference that compares transcriptome and epigenome profiles, and provides an alternative strategy for directing experimental measurements.

Low temperature solid oxide fuel cells (SOFCs) with metal oxide composite cathode on the ceria–carbonate composite electrolyte have shown promising performance. However, the role of individual elem ...

Potato starch-based activated carbon spheres (PCS) were prepared by CO2 activation in this paper. The morphology of PCS was examined by scanning electron microscopy. Effects of activation temperature and time on characteristics of PCS were studied by N2 adsorption method, and the effect of pore structure of PCS on its electrochemical performances was studied by galvanostatic charge–discharge and cyclic voltammetry. The results indicate that PCS is hollow and retain the morphology of potato starch granule. Activation time has a more important effect on the formation and widening of micropores, the ratios of mesopore reaches 41% when activation time is prolonged to 120 min at 900 °C. Electrochemical test indicates good wetting property and conductivity of electrode material are beneficial to high specific capacitance, and mesopores play an important role in the fast transfer of electrolyte ions.

Using green needle coke (GNC) based amphiphilic carbonaceous material (ACM) as the only raw material, carbon aerogels was successfully synthesized via a very simple method at room temperature, followed by drying at ambient pressure and carbonization in an inert atmosphere. The resulting product was piled up by highly connected nano-particles with diameters of 30–50 nm, which constructed a 3-D architecture also providing certain mesopores and macropores. After being carbonized at 500 °C, the diameter of nano-particles shrank to about 25 nm and still maintain some connective ligament parts. Meanwhile, N2 sorption analysis showed that the SBET of CAs-500 is 292 m2/g and had a wide pore size distribution from micropores to macropores. After further activation, such special dimensional structure guaranteed the carbon aerogel a potential electrode material for electrochemical capacitor.

Ceria-carbonate composite materials have been widely investigated as candidate electrolytes for solid oxide fuel cells operated at 300-600 degrees C. However, fundamental studies on the composite e ...

Carbon microspheres were synthesized through polymerization of urea/formaldehyde in the presence of formic acid as catalyst, followed by drying and carbonization in an inert atmosphere. The samples were characterized by SEM, XRD, HRTEM, elemental analysis and XPS. The obtained carbon microspheres were amorphous indicated by the results of XRD and HRTEM. The changes of nitrogen functionalities at 400–1000 °C were determined by XPS. The fraction of pyridine nitrogen and pyrrole/pyridone nitrogen decreased with increasing temperature, whereas the amount of quaternary nitrogen increased.

The effects of primary quinoline insoluble (PQI) on the formation process of mesocarbon microbeads (MCMBs) have been investigated through comparison of microstructural characteristics of PQI and MCMBs, which were comprehensively identified by Fourier transform infrared, solid-state 13C nuclear magnetic resonance and X-ray diffraction. The results showed that PQI had similar polyaromatic structure to MCMBs in terms of carbon aromaticity, which indicated that PQI could overcome the high energy barrier of a new mesophase formation and decrease the activation energy of MCMBs formation. Thus, it was concluded that PQI could act as the nuclei for mesophase growth. The nucleation of PQI was further justified by the of-course growth of the secondary MCMBs.

Amphiphilic carbonaceous material (ACM), with nanoscale dispersion in alkaline aqueous solutions, is synthesized from green needle coke. As a special precursor with small particle size, plenty of functional groups and widened d002 simultaneously, ACM guarantees subsequent ACM-based activated carbons (AACs) with high specific surface area over 3000 m2 g−1 as well as well-developed mesoporous structure after KOH activation. Such pore properties enable AACs’ high performances as electrode materials for electric double-layer capacitors (EDLCs). In particular, surface area up to 3347 m2 g−1 together with notable mesopore proportion (26.9%) gives sample AAC814 outstanding EDLC behaviors during a series of electrochemical tests including galvanostatic charge/discharge, CV and electrochemical impedance spectroscopy. The electrode gets satisfactory gravimetric and volumetric specific capacitance at the current density of 50 mA g−1, up to 348 F g−1 and 162 F cm−3, respectively. Furthermore, for the mesoporosity, there is only a slight capacitance reduction for AAC814 as the current density reaches 1000 mA g−1, indicating its good rate performance. It is all the ACM's unique characteristics that make AACs a sort of competitive EDLC electrode materials, both in terms of specific capacitance and rate capability.

It is known that mesocarbon microbeads (MCMBs) have ordered structure and grow after absorbing molecules from pitch. However, the structure of pitch used for preparing MCMBs is disordered. Thus question of whether there is a region where the molecules absorbed from pitch change their orientations is a very interesting problem. In this paper, an interface between MCMBs and their pitch matrix has been found and the structure of the interface was observed by scanning electron microcopy. There are some ordered regions in the interface but the number of ordered regions in the interface is much fewer than the number inside the MCMBs. This indicates that the interface between the MCMBs and the pitch is the region where the orientations of the molecules absorbed from pitch change.

Carbon spheres perfectly retaining the original morphology of potato starch were prepared by a two-step process including stabilization and carbonization. The potato starch was first stabilized at 210 °C under air, and the stabilized samples were then carbonized at 600 °C for 1h under N2 atmosphere. In the process, stabilization treatment was the main step. The mechanism of stabilization was investigated by thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and differential scanning calorimetry, and the morphology of the carbon spheres was characterized by scanning electron microscopy (SEM). Results show that during stabilization, the loss of water and the occurrence of decomposition and condensation reactions result in the destruction of the crystallite structure in the original potato starch. Thus, during the carbonization step, further intermolecular cross-linking makes microcrystalline melting very difficult. This promotes the formation of monodispersed carbon spheres. The SEM results show that only if the potato starch undergoes adequate stabilization treatment (e.g., 12 h) before carbonization, can the carbon spheres perfectly retain the original shape of the potato starch.

Mesophase pitch (MP)/exfoliated graphite nanoplatelets (GNPs) nanocomposite has been prepared by an efficient method with an initiation of graphite intercalation compounds (GIC). X-ray diffraction, optical microscopy, high-resolution transmission electron microscopy and scanning electron microscopy analysis techniques are used to characterize the samples. It is observed that GIC has exfoliated completely into GNPs during the formation of MP/GNPs nanocomposite and the GNPs are distributed uniformly in MP matrix, which represent a conductive path for a movement of electrons throughout the composites. Electrochemical tests demonstrate that the carbonized MP/GNPs nanocomposite displays higher capacity and better cycle performance in comparison with the pure carbonized MP. It is concluded that such a large improvement of electrochemical performance within the nanocomposite may in general be related to the enhanced electronic conductivity, which is achieved by good dispersion of GNPs within MP matrix and formation of a 3D network of GNPs.

A composite of samarium doped ceria (SDC) and a binary carbonate eutectic (52 mol% Li2CO3/48 mol% Na2CO3) is investigated with respect to its morphology, conductivity and fuel cell performances. Th ...

Two kinds of mesophase pitches with different softening points were prepared at different soaking times and directly activated with KOH to study the effects of the softening point on the textural characteristics of the resulting activated carbons and their behavior as electrodes in capacitors. Results show that the softening points of the two mesophase pitches are 280 and 330 (C, and the specific surface areas of the activated carbons are 1 337 and 1 300 m 2 ·g −1 , respectively. The specific capacitance of the higher softening point mesophase pitch-derived carbon is higher (255.6 F·g −1 ) than that of the lower softening point mesophase pitch-derived carbon (190.8 F·g −1 ) at the same current density. Cyclic voltammograms show that the lower softening point mesophase pitch-derived carbon exhibits better rectangular-shaped I-V curves. The softening points of the mesophase pitches prepared from even the same precursor can significantly affect the electrochemical performance of the resulting activated carbons.

Direct carbon fuel cell (DCFC) is a kind of high temperature fuel cell using carbon materials directly as anode. Electrochemical reactivity and surface property of carbon were taken into account in ...

Activated phenol resin-based carbon spheres (APCS) electrodes with high double layer capacitance and good rate capability were prepared from phenol resin-based spheres (PS) at different carbonization temperatures prior to KOH activation. The carbonization temperature has a marked effect on both the pore structure and the electrochemical performances of the APCS in 6 M KOH electrolyte. APCS carbonized at 600 °C results in higher specific surface area and larger pore size, and hence higher capacitance and better rate capability. The specific capacitance of the APCS in 6 M KOH aqueous solution can be as high as 282 F g −1 . It remains 252 F g −1 as the current density increases to 1000 mA g −1 .

Nano-iron/mesocarbon microbead composites have been synthesized from a coal tar pitch by heating at 415 °C with ferrocene under pressure. The resulting composites were characterized using the combined techniques including SEM, TEM, XRD and EDS. The effect of ferrocene addition on the growth and structure of mesocarbon microbeads was discussed. It was found that nano-iron particles were of sizes 10–40 nm and mainly existed in the form Fe–O and Fe 1− x S. The iron particles, which had dispersed homogeneously in pristine and carbonized spheres, accelerated the nucleation and growth of spheres and consequently enhanced the structural ordering of spheres. The addition of ferrocene introduced a tendency to order in the microtexture of spheres.

Potato starch-based activated carbon spheres (PACS) were prepared from potato starch by stabilization, carbonization followed by activation with KOH. The obtained PACS are hollow and retain the original morphology of potato starch with decrease in size, as shown by scanning electron microscopy. Modification of textural properties of the PACS was achieved by varying the carbonization temperature and the ratio of KOH/PCS. The results of N2 adsorption isotherms indicate that the samples prepared are mainly microporous. The electrochemical behaviors of the hollow PACS were studied by galvanostatic charge–discharge, cyclic voltammetry, and impedance spectroscopy. The results indicate that high specific capacitance of 335 F/g is obtained at current density 50 mA/g for PACS with specific surface area 2342 m2/g. Only a slight decrease in capacitance, to 314 F/g, was observed when the current density increases to 1000 mA/g, indicating a stable electrochemical property.

Graphene materials (GMs) as supercapacitor electrode materials have been investigated. GMs are prepared from graphene oxide sheets, and subsequently suffer a gas-based hydrazine reduction to restore the conducting carbon network. A maximum specific capacitance of 205 F/g with a measured power density of 10 kW/kg at energy density of 28.5 Wh/kg in an aqueous electrolyte solution has been obtained. Meanwhile, the supercapacitor devices exhibit excellent long cycle life along with ∼90% specific capacitance retained after 1200 cycle tests. These remarkable results demonstrate the exciting commercial potential for high performance, environmentally friendly and low-cost electrical energy storage devices based on this new 2D graphene material.

Berberine is one of the main alkaloids of Rhizoma coptidis which has been used for patients with gastrointestinal disorders. The major aim of this study was to investigate the effect of berberine on tight junction. Caco-2 cells were treated with various concentration of berberine. We observed the integrity of tight junction by measuring the transepithelial electrical resistance (TEER), and also studied the effect of berberine on morphology of tight junction and tight junction protein. These findings showed the first time that berberine could reduce epithelial gut permeability, and might help explain the possible mechanisms of anti-diarrhea activity of berberine.

Silica aerogel (SiO2 aerogel) was prepared by sol–gel method from tetraethyl orthosilicate hydrolyzation and has been characterized by scanning electron microscopy and N2 adsorption for its surface structure, surface area, and pore-size distribution. Constant current charge–discharge technique, cyclic voltammetry, and electrochemical impedance spectrum were employed for its specific capacitance and equivalent series resistance. The results showed that the maximum specific capacitance of SiO2 aerogel electrode in 1 M Et4NBF4/PC electrolyte was 62.5 F g−1. In addition, the SiO2 aerogel capacitor exhibits excellent long-term stability with no significant degradation after 500 charging and discharging cycles. Therefore, the application of high surface area SiO2 aerogel as electrodes in supercapacitor devices is promising.

In this study, activated carbon (AC)-Fe3O4 nanoparticles asymmetric supercapacitor cells have been assembled and characterized in 6 M KOH aqueous electrolyte for the first time. The nanostructure Fe3O4 was prepared by the microwave method. It only cost several minutes to prepare magnetite nanoparticles with average particle size of 35 nm. The electrochemical performances of the hybrid AC-Fe3O4 supercapacitor were tested by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge−discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within potential range 0−1.2 V. The supercapacitor delivered a specific capacitance of 37.9 F/g at a current density of 0.5 mA/cm2. The result of cyclic characteristic test showed that it also can keep 82% of initial capacity over 500 cycles.

A novel composite material based on mixture of samarium-doped ceria (SDC)-carbonate was studied as electrolyte in low temperature solid oxide fuel cells. The phase and microstructures of composite ...

Graphite foams were prepared from the mesophase-pitch with addition of natural graphite and the relationship between properties and structure of these foams was investigated in detail. These graphite foams possessed high specific compressive strength and experimental results show that less microcracks appeared on the cell walls of foam by adding of natural graphite. The specific compressive strength increased from 2.0 to 5.84 MPa/g cm3 with the addition of 30 wt% natural graphite, and the inter layer spacing of graphite foams decreased with the increase of the natural graphite content in the pitch. In addition, the optical micrograph shows that the anisotropic domain size of the foam decreased with the addition of natural graphite and it also affects the compressive strength of the foams.

The carbon materials prepared from polyimide (PI) resin film were investigated by TG-DTG, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. TG-DTG study revealed that the weight loss of PI resin film during carbonization occurred in three stages, and the most serious changes occurred at 605.5°C. XRD results indicated that a disorder structure occurred after the carbonization at 600°C and graphite crystallite appeared gradually with increasing the temperature. And PI resin film still presented some characteristics of nongraphitizing carbon, after graphitizing at 2600°C. XPS analysis identified that pyrrole type nitrogen was a main component of surface nitrogen atoms after carbonization. When the temperature reached 2600°C, nitrogen atoms disappeared totally; the reason why oxygen atoms still existed in the material at so high temperature was our subject of interesting matter in the later study. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

A simple method for preparing the mesophase-pitch-based carbon foams at low pressures through prolonging the soaking time in the preparation process of the mesophase pitch was disclosed. The physical properties, morphologies and the crystal structure of the as-obtained foams were investigated. Bulk density of the resultant carbon foams cover a range 0.514–0.624 g/cm3, under the preparation pressure range 0.5–2 MPa. The SEM micrographs revealed that the thermal shrinkage of the graphitized foams derived from the higher softening point mesophase pitch was less than that of the foam from the lower softening point; Optical micrographs showed that higher softening point mesophase pitch derived carbon foams exhibited better orientation and less microcracks in both junctions and ligaments; The XRD results revealed that higher softening point pitch derived graphitized foams exhibited smaller interlayer spacing and larger crystallite size. The properties of the carbon foam can be severely affected by the properties of the precursor, so it is critical to tailor the properties of the pitch precursor so as to obtain high performance and low cost products.

An isotropic pitch and an anisotropic pitch with similar softening point were chosen to be precursors for activated carbons (ISO and ANISO, respectively). Chemical activations with same conditions were carried out and the effects of microstructure of precursors on characteristics of activated carbons were discussed. Isotropic pitch with more noncrystallite carbon atoms or edge carbon atoms on the microstructural defects had more reactive ability and more pores were manufactured through sufficient chemical activation. Electric double-layer capacitors (EDLC) were made with the two activated carbons as electrode materials and 1 M Et4NBF4/PC as the electrolyte. The performance of EDLC with the ISO has higher specific capacitance (43.5 F g−1) than the ANISO (21.3 F g−1) and has better power performance and lower resistance than the latter.

Oxide mixtures MO–SDC, M = Cu, Ni, Co, SDC = Ce 0.9 Sm 0.1 O 1.95 were synthesized by employing a citrate/nitrate combustion technique. Two kinds of Carbon materials, activated carbon (AC) and vapor grown carbon fiber (VGCF) were homogeneously dispersed into the MO–SDC. The materials can be used as anodes to fabricate single cells using a uniaxial die-press method. The sintering temperature was studied to optimize cell performance. Experimental results showed that cells sintered at 700 °C had better performance. When the temperature was above 750 °C, the cells were severely distorted, and cannot be tested. Compared with the basic MO–SDC anode, AC and VGCF improve the solid oxide fuel cell (SOFC) anode properties, due to a change of the microstructures of the anode materials which enhance their electron conductivity. Single cell performances were evaluated by I–V measurements, and when 1.25 wt.%VGCF was introduced into the MO–SDC by ball-milling, termed: 1.25 wt.%VGCF–MO–SDC, the 1.25 wt.%VGCF–MO–SDC anode material could achieve the highest power density of up to 0.326 W cm −2 with H 2 as fuel. The calcination temperature of the MO–SDC dry gel also strongly influenced the electrochemical performance of the 1.25 wt.%VGCF–MO–SDC material. XRD spectra for each calcined temperature and the I–V measurement both suggest that calcinations at 550 °C for 1 h are suitable. 1.0 wt.%AC–MO–SDC and 1.25 wt.%VGCF–MO–SDC have similar performance when the cell was fed in methanol/3%H 2 O, and the corresponding power density was up to 0.253 W cm −2 . Traces of carbon were found in the off-gases.

The utilization of the microfabrication technique to fabricate advanced computing chips has exponentially increased in the last few decades. Needless to say, this fabrication technique offers some unique advantages to develop micro-systems. Though many conventional microfabrication techniques today uses very harsh chemicals, the authors believe that the manipulation of system components and fabrication methods may aid in the utilization of the microfabrication techniques used in fabricating computer chips to develop advanced biological microfluidic systems. Presented in this paper is a fabrication approach in which popular fabrication methods and techniques are coupled together to develop an integrated system that aids in the fabrication of cell-laden microfluidic systems. This system aims to reduce the uses of harsh chemicals and decreases the lengthy fabrication time. Additionally, this integrated system will enable the printing of cells as the microfluidic chip is being fabricated. To demonstrate the unique capabilities of the integrated system, an advanced microfluidic chip is being fabricated and investigated. The advanced chip will feature the investigation of cancer cells in a co-cultured microfluidic environment. The investigations presented demonstrate co-cultures in a microfluidic chip, advanced cell printing with localized surface enhancement, cell integration, and full additive fabrication of a microfluidic chip.

The rational design and fabrication of electrode materials is a significant, yet highly challenging task. In this work, mesoporous Fe3O4 nanostructures featuring 3D structured hollow nanoparticles decorated by N-doped graphene with an average size of 10 nm were synthesized by a combination of hydrothermal and post carbonization techniques, and were subsequently studied as an anode material for lithium ion batteries. This hollow nanoarchitecture anchored on N-doped graphene sheets, possessing a large specific surface area and enhanced volumetric capacity, offers maximum lithium storage, facilitates rapid electrochemical kinetics, buffers volume changes during the lithium ion insertion and extraction processes, and removes detrimental active sites due to N incorporation, which is important for improving the recycling ability of anode materials. High reversible capacities, excellent rate-capability and stable performance were continuously observed. Accordingly, graphene-based composites that intercalate hollow Fe3O4 nanocrystals into N-doped graphene sheets have been demonstrated to be promising electrode materials for energy storage.

Mesocarbon microbeads (MCMB) were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440°C for Ih. By investigating the morphology of mesophase spheres and the structure of the MCMB carbonized at 1000°C for Ih using scanning electron microscope (SEM) and XRD, it was found that phenolic resin accelerated the formation and coalescence of mesophase spheres. Some of the obtained MCMB were bi- or tri-spheres with the distorted microtextural carbon layers. Hexamethylenetetramine in the pitch modified by phenolic resin accelerated the condensation of phenolic resin and consequently expedited the combination of mesophase spheres, which was proved by the formation of some tetra-spheres. Owing to the cross-linkage of the additives, MCMB with complex structure were obtained.

To observe the changes in forkhead/winged helix transcription factor p3(Foxp3), regulatory T cells (Treg), retinoid-related orphan receptor gamma (RORγt) in rat model of chronic obstructive pulmonary disease (COPD).Twenty Sprague-Dawley (SD) rats were randomly divided into normal control group and COPD model group, with 10 rats in each group. The COPD model was reproduced by smoke inhalation and tracheal instillation of lipopolysaccharide (LPS), and no such treatment was conducted in normal control group. Twenty-eight days after the model reproduction, the pulmonary function was determined, the pathological changes of lung tissue were observed with haematoxylin-eosin (HE) staining, interleukins (IL-6, IL-10) in serum were detected by enzyme-linked immunosorbent assay (ELISA), CD4⁺ CD25⁺ Foxp3⁺ Treg of peripheral blood was determined by flow cytometry, and the expressions of Foxp3, RORγt, IL-17 protein in lung tissue were assayed by Western Blot.Under light microscope, significal interstitial infiltration of inflammatory cells was found in alveoli and interstitial tissue of the lung, and destruction of alveolar tissue, alveolar wall thinning, and even rupture to fuse into bullae, and bleeding into alveoli in different degress could be observed. Compared with the normal control group, forced vital capacity (FVC), forced expiratory volume in 0.3 second (FEV0.3), FEV0.3/FVC, peak expiratory flow (PEF) in model group were significantly decreased [FVC (mL): 8.04 ± 2.03 vs. 9.97 ± 2.14, FEV0.3 (mL): 6.16 ± 2.23 vs. 8.84 ± 2.12, FEV0.3/FVC: 0.70 ± 0.09 vs. 0.85 ± 0.11, PEF (mL/s): 33.56 ± 4.76 vs. 40.14 ± 5.64, P0.05 or P0.01]. Serum IL-6 was obviously increased (ng/L: 93.17 ±20.96 vs. 76.28 ± 13.24, P0.05), IL-10 was significantly decreased (ng/L: 78.62 ± 15.17 vs. 104.34 ± 19.46, P0.01), and CD4⁺ CD25⁺ FoxP3(+)Treg was significantly diminished [(2.75 ± 0.83)% vs. (4.16 ± 1.14)%, P0.01] in model group compared with those in the normal control group. The expression of Foxp3 protein in lung tissue in model group was significantly down-regulated compared with that in the normal control group (gray scale: 0.38 ± 0.15 vs. 0.63 ± 0.11, P0.01), and RORγt and IL-17 protein expressions were significantly up-regulated [RORγt (gray scale): 0.96 ± 0.23 vs. 0.47 ± 0.11, IL-17 (gray scale): 1.02 ± 0.24 vs. 0.34 ± 0.08, both P0.01]. Correlation analysis showed that FEV0.3 was positively correlated with Foxp3 (r=0.585, P0.05), and FEV0.3/FVC was negatively correlated with IL-6 and RORγt (r=-0.655, r=-0.607, both P0.05). PEF was positively correlated with Treg (r=0.573, P0.05), and negatively correlated with IL-17 (r=-0.198, P0.05). IL-6 was negatively correlated with Foxp3(r=-0.603, P0.05),and positively correlated with RORγt (r=0.588, P0.05). IL-10 was positively correlated with Treg (r=0.573, P0.05). Treg was positively correlated with Foxp3 (r=0.607, P0.05), and negatively correlated with IL-17 (r=-0.569, P0.05). Foxp3 was negatively correlated with RORγt (r=-0.591, P0.05). RORγt was positively correlated with IL-17 (r=0.578, P0.05).There is a relationship among decreased pulmonary function, inflammation and imbalance of Foxp3/Treg and RORγt/Th17 in COPD.

In the present experiments, mesocarbon microbeads (MCMBs) were prepared from a coal tar pitch with or without micro-Al2O3 powder under 410 °C for 7 h to study the influence of alumina on the MCMBs. OM, SEM, XRD and EDS were used to analyze the as-received MCMBs, among which SEM was used firstly to observe the microtextures of MCMBs systemically. The results show that the irregular alumina particles, which have been enwrapped in the MCMBs, impede the growth of the mesophase spheres and consequently decrease the yield of them. The textural layers of the formed MCMBs were disturbed by the aluminum oxide particles. Although the alumina in the spheres could escape and seems to maintain the sphericity of MCMBs during the graphitization, the bad influence would remain. In addition, ash analysis of MCMBs was carried out, which further confirmed the existence of alumina particles in the as-received spheres and the absence of them in the graphitized spheres. In conclusion, alumina in raw pitches is disadvantageous for the growth and the final structure of MCMBs and should be removed in advance if high yield and regular structure are expected.

Li 4 Ti 5 O 12 ultrafine powders were synthesized by hydrothermal method using aqueous TiCl 4 solution and LiOH·H 2 O as raw materials. The prepared particles comprise crystalline spinel-type Li 4 Ti 5 O 12 with the size in the range of 100–400 nm without any agglomerate. Electrochemical measurements were then carried out to evaluate the anode performances of Li 4 Ti 5 O 12 samples in lithium-ion batteries. The initial discharge capacity is 172.8 mAh g − 1 at 0.1 C and 142.4 mAh g − 1 at 10 C. It maintained its capacitance to as high as 122.2 mAh g − 1 (87.3% retention) at 10 C even after 100 cycles, indicating a good rate and cyclic performance. This novel non-organic hydrothermal method presented an economical, facile and green pathway for Li 4 Ti 5 O 12 as anode material in lithium-ion batteries of high power densities.

Hollow carbon microspheres (HCS) were prepared from potato starch by ZnCl2 activation. The morphology and surface areas of the HCS were studied by scanning electron microscopy and N2 adsorption method, respectively. The results show that the HCS with bowl-like and eggshell-like structures are microporous materials. The preparation mechanism of the HCS was investigated by X-ray diffraction and thermogravimetric analysis. The results indicate that basic zinc chloride formed during impregnation decomposes into ZnO, HCl and H2O. ZnO and HCl play an important role in the preparation of the HCS. Moreover, removal of ZnO grains by HCl washing contributes to the total surface areas of the HCS.