Enhanced electrical conductivity of anticorrosive coatings by functionalized carbon nanotubes: effect of hydrogen bonding.

Carbon nanotubes and nanofibers (CNFs) are well-known nano additives to produce coating materials with high electrical and thermal conductivity and corrosion resistance. In this paper, coating materials incorporating hydrogen bonding offered significantly lower electrical resistance. The hydrogen bonding formed between functionalized carbon nanotubes and ethanol helped create a well-dispersed carbon nanotube network as the electron pathways. Electrical resistivity as low as 6.8 Ω cm has been achieved by adding 4.5 wt% functionalized multiwalled carbon nanotubes (MWNT-OH) to 75%polyurethane/25%ethanol. Moreover, the thermal conductivity of polyurethane was improved by 332% with 10 wt% addition of CNF. Electrochemical methods were used to evaluate the anti-corrosion properties of the fabricated coating materials. 75%polyurethane/25%ethanol with the addition of 3.0 wt% of MWNT-OH showed an excellent corrosion rate of 5.105 × 10-3mm year-1, with a protection efficiency of 99.5% against corrosive environments. The adhesion properties of the coating materials were measured following ASTM standard test methods. 75%polyurethane/25%ethanol with 3.0 wt% of MWNT-OH belonged to class 5 (ASTM D3359), indicating the outstanding adhesion of the coating to the substrate. These nanocoatings with enhanced electrical, thermal, and anti-corrosion properties consist of a choice of traditional coating materials, such as polyurethane, yielding coating durability with the ability to tailor the electrical and thermal properties to fit the desired application.

A Rheological Investigation of Carbon Nanotube Grease.

The use of carbon nanotubes (CNTs) as a thickening agent in polyalphaolefin oils to create CNT-grease has significant merit. Given the abnormally high thermal conductivities of CNTs, it is conceivable that a CNT-grease would exhibit excellent thermal conductivity. The rheological response of CNT-greases is important for two reasons: to determine if the grease will have sufficient lubricating properties and to provide critical information on the structure and particle-particle interactions of CNT suspensions. The viscoelastic response and evidence of creep recovery support the theory of the stable 3 Dimensional network (3D) formation in the CNT-grease. The elastic response indicates that significant energy is needed to dismember the network structure and initiate viscous flow. The macroscopic rheological investigation provides additional information regarding the structure of CNT-grease and particle-particle interactions at high SWNT concentrations, ~10.0 wt. The knowledge gained concerning the structure of CNT suspensions will allow its manipulation to achieve better thermal properties.

Carbon Nanotube Inkjet Printing Based Resettable Sensor for Online Scale Monitoring.

In this paper, a new type of sensor and associated system for complete online monitoring of scale deposition with great accuracy and reliability is fabricated and characterized. The system is based on carbon nanotubes (CNTs), which have unique sensing/electronic properties along with physical and chemical stability in corrosive and hostile environments required for the oil and gas application. CNTs inkjet printing technique is used to fabricate the CNTs sensor. The sensitivity of the films, real time monitoring of brine solution, stability of the films in various solvents and fluids and the ability of setting and resetting of the sensor are studied. The results of these studies indicate that adding of one brine solution on the surface of the CNTs inkjet printing increases the resistance from 0.50 kΩ to 1.50 kΩ. The CNTs inkjet printing sample is found to be stable even after 48 hours of soaking the whole sample in DI-water. This sensor not only shows good sensing response for detection of the deposition of brine, but can also be easily reset back many times by just wash it with DI-water. This simple sensor is ideally suited for real time monitoring and the response time of the film is found to be from 15­30 s.

Capacitive deionization performance of asymmetric nanoengineered CoFe2O4 carbon nanomaterials composite.

Capacitive deionization (CDI) is a relatively new technique that uses electric double layer (EDL) effects, high-affinity chemical groups, redox-active materials, and membrane capacitive electrosorption principle for the desalination. In this paper, hydrothermal synthesis of cobalt ferric oxide (CFO) metal oxide nanoparticles (NPs) coupled with the vacuum filtration method, or the freeze-drying method is used to fabricate high-performance nanocomposites: CFO-graphene, CFO-CNTs, and CFO-3DrGO. Two times of hydrothermal reaction methods were conducted to fabricate the CFO-3DrGO nanoengineered as a pseudocapacitive/EDL electrode. The results have demonstrated that the SAC of CFO-3DrGO/CFO (64.5 mg g-1) is greater than that of the CFO-graphene/CFO (55.16 mg g-1) and CFO-CNTs/CFO (21.5 mg g-1) due to the better surface area of the CFO-3DrGO nanocomposite (330 m2 g-1). The higher surface area of the CFO-3DrGO is due to the porous and interconnected 3D structure of the 3DrGO, and it provides a larger surface area to form EDL capacitance. In addition, the added porous 3DrGO entangled with the spinel crystals (CoFe2O4) in the composite allowed for a quick ion diffusion across the interconnected open macroporous structures.

Ether-based electrolytes enable the application of nitrogen and sulfur co-doped 3D graphene frameworks as anodes in high-performance sodium-ion batteries.

The development of graphitic carbon materials as anodes of sodium-ion batteries (SIBs) is greatly restricted by their inherent low specific capacity. Herein, nitrogen and sulfur co-doped 3D graphene frameworks (NSGFs) were successfully synthesized via a simple and facile one-step hydrothermal method and exhibited high Na storage capacity in ether-based electrolytes. A systematic comparison was made between NSGFs, undoped graphene frameworks (GFs) and nitrogen-doped graphene frameworks (NGFs). It is demonstrated that the high specific capacity of NSGFs can be attributed to the free diffusion of Na ions within the graphene layer and reversible reaction between -C-Sx-C- covalent chains and Na ions thanks to the large interplanar distance and the dominant -C-Sx-C- covalent chains in NSGFs. NSGF anodes, therefore, exhibit a high initial coulombic efficiency (ICE) (92.8%) and a remarkable specific capacity of 834.0 mA h g-1 at 0.1 A g-1. Kinetic analysis verified that the synergetic effect of N/S co-doping not only largely enhanced the Na ion diffusion rate but also reduced the electrochemical impedance of NSGFs. Postmortem techniques, such as SEM, ex situ XPS, HTEM and ex situ Raman spectroscopy, all demonstrated the extremely physicochemically stable structure of the 3D graphene matrix and ultrathin inorganic-rich solid electrolyte interphase (SEI) films formed on the surface of NSGFs. Yet it is worth noting that the Na storage performance and mechanism are exclusive to ether-based electrolytes and would be inhibited in their carbonate ester-based counterparts. In addition, the corrosion of copper foils under the synergetic effect of S atoms and ether-based electrolytes was reported for the first time. Interestingly, by-products derived from this corrosion could provide additional Na storage capacity. This work sheds light on the mechanism of improving the electrochemical performance of carbon-based anodes by heteroatom doping in SIBs and provides a new insight for designing high-performance anodes of SIBs.

Redox signaling regulates the skeletal tissue development and regeneration.

Skeletal tissue development and regeneration in mammals are intricate, multistep, and highly regulated processes. Various signaling pathways have been implicated in the regulation of these processes, including redox. Redox signaling is the signal transduction by electron transfer reactions involving free radicals or related species. Redox homeostasis is essential to cell metabolic states, as the ROS not only regulates cell biological processes but also mediates physiological processes. Following a bone fracture, redox signaling is also triggered to regulate bone healing and regeneration by targeting resident stromal cells, osteoblasts, osteoclasts and endothelial cells. This review will focus on how the redox signaling impact the bone development and bone regeneration.

Correlation between TNF-α -308 and +489 Gene Polymorphism and Acute Exacerbation of Chronic Obstructive Pulmonary Diseases.

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is becoming a common respiratory disease, leading to increased morbidity and mortality worldwide. Tumor necrosis factor-alpha (TNF-α) is a powerful proinflammatory cytokine involved in the pathogenesis of AECOPD. Therefore, we proposed a close correlation between the TNF-α polymorphism [-308G/A (rs1800629), +489G/A (rs1800610)] and the disease progress of patients with AECOPD. Comparison of the TNF-α genotypes between the 198 AECOPD diagnosed patients groups and 195 healthy peoples suggested their significant differences of the three genotypes (AA, GA, GG) distribution for TNF-α -308 (P < 0.05), but no differences of that for TNF-α +489. We found that patients with TNF-α -308 GA/AA genotypes showed smaller adjacent arterial diameter, thicker bronchial wall, higher bronchial artery ratio, higher bronchial wall grading, and higher frequency of acute exacerbations than those with TNF-α -308 GG genotype. Patients with TNF-α +489 GA/AA genotypes showed the same AECOPD properties as patients with TNF-α -308 except for the high frequency of acute exacerbations. Further experiment showed that the TNF-α -308 and+489 gene polymorphisms could affect the expression level of TNF-α in macrophages, suggesting the involvement of the macrophage population in disease regulation of AECOPD patients with TNF-α -308G/A and+489G/A genotype heterogeneity. In conclusion, the TNF-α -308 G/A genotype was related to AECOPD susceptibility and progress, while the TNF-α +489G/A genotype was related to AECOPD progress, but not AECOPD susceptibility.

In Situ Transformed Carbon Fibers/Al2O3 Nanocomposites Using Cao-MgO-SiO2 Sintering Agent.

In Situ transformed carbon fibers/Al2O3 ceramic matrix nanocomposites with Cao-MgO-SiO2 sintering agent were prepared by hot-pressed sintering technology in vacuum. In the sintering process, pre-oxidized polyacrylonitrile fibers (below named as pre-oxidized PAN fibers) were used as the precursors of In Situ transformed carbon fibers. The micro/nanostructure of composites and interface between In Situ transformed carbon fibers and matrix were investigated, as well as the properties of composites. The results showed that the composites could be sintered well at a relatively low temperature of 1650 °C. During the sintering, the precursors, pre-oxidized PAN fibers, were In Situ transformed into carbon fibers, and the In Situ transformed carbon fibers had the graphitelike structure along the fiber axial direction. The carbon atoms arrangement in the surface layer of the fiber was more orderly than the core. A typical diffraction peak of carbon fiber at 26°, which corresponded to the (002) crystal plane, was observed, and the inter-planar spacing was approximately 0.34 nm. The CaO-MgO-SiO2 sintering agent formed MgAl2O4 and CaAl2Si2O8 phases in the interface between In Situ transformed carbon fibers and matrix, therefore improving the interface bonding, and thereby modifying the mechanical properties of the composites.

Mechanical properties of epoxy nanocomposites reinforced with very low content of amino-functionalized single-walled carbon nanotubes.

Functionalized single-walled carbon nanotubes (SWNTs) with amino groups were prepared by oxidation, acylation, and amidation of SWNT surfaces. Epoxy/SWNT composite membranes were fabricated using a very low content of amino-grafted SWNTs (< or = 0.08 wt%) as fillers. SWNTs with amino groups acted as a curing agent, covalently bonding to the epoxy matrix. The influence of SWNT content on the mechanical properties of epoxy/amino-functionalized SWNT composite membrane was investigated. It is found that the tensile strength of composites is enhanced with the increase of SWNTs. Only 0.01 wt% of SWNT-R-NH, leads to improvement of the epoxy tensile strength by 9.5%, and 0.08 wt% of SWNT-R-NH2 increased tensile strength by 13.6%. For comparison purposes, epoxy/pristine-SWNT films were also prepared. The improvement of the tensile strength of the amino-functionalized SWNTs system is more remarkable than that of pristine SWNT system at very low weight-percentage loading. The amino groups on the surface of SWNTs can be covalently attached to the epoxy matrix, which effectively improves the dispersion and adhesion of SWNTs in epoxy. This leads to the enhancement in mechanical properties of the epoxy composite. Mechanical results between functionalized and pristine nanotubes are discussed in detail.

[Evaluation of therapeutic effects of the ultramicro needle knife combined with cervical spine fine adjusting on youth cervical curvature abnormality case].

OBJECTIVE: To study the therapeutic effects of the ultramicro needle-knife combine with cervical spine fine adjusting on youth cervical curvature abnormality case. METHODS: From November 2016 to October 2018, 88 young patients with abnormal curvature of cervical spine were treated. Due to loss of follow up, 86 cases were actually completely including 37 males and 49 females, ranging in age from 20 to 40 years old, with an average of (30.55±5.21) years old, and the course of disease ranged from 1 to 42 months, with a mean of (14.21±7.38) months. All the patients were divided into two groups:treatment group (44 cases) and control group (42 cases). The patients in the treatment group were treated with ultramicro needle-knife and cervical spine fine adjusting, and the patients in the control group were treated with conventional acupuncture and manipulation. The treatments were done 1 time per week in the treatment group while 3 times per week in control group every week, with a duration of 3 weeks for both groups. Before treatment, 3 weeks after treatment, and at the end of 1 month follow-up, the score of neck pain questionnaire(NPQ), range of the motion(ROM) in the cervical region and the D values of cervical physiological curvature were recorded. The efficacy at the end of treatment and in the follow up was evaluated. During the treatment, the patients were also required to correct the bad posture in daily life, to sleep in a low pillow position, and put a moderately columnar pillow behind the neck for 0.5 hours every morning and evening. RESULTS: Two patients in the control group were dropped out after 3 weeks treatment. No adverse reactions were found in the 2 groups during the treatment period. Compared with those before treatment, all scores at all the observation time points were significantly improved between two groups after treatment(all P<0.05). The NPQ scores of cervical symptoms were different significantly between two groups(all P<0.05). The changing range of the the NPQ score of cervical symptoms and cervical spine alignment curve of the treatment group were better than those of the control group (P<0.05).There was statistical difference in NPQ scores between different time points, in the other words, there was time effect(F=203.63, P=0.000). There was interaction between time factor and group factor(F=4.964, P=0.012). There was no statistical difference in the changing range of the ROM score between two groups (all P>0.05). There was statistical difference in ROM scores between different time points, there was time effect (F=240.32), P=0.000). There was no interaction between time factor and group factor (F=0.311, P=0.734). The effective rate of the treatment group and control group were 90.91%(40 / 44) and 80.95%(34 / 42) respectively, the treatment group was more effective than the control group (P<0.05). During the follow-up period, the effective rate of the treatment group and the control group were 84.09%(37 / 44) and 76.19%(32 / 42) respectively. Obviously, the difference of total effective rate between two groups had no statistical signification(P>0.05) in the follow-up duration. CONCLUSION: The method of needle knife combined with cervical spine fine adjusting has a better therapeutic efficiency than conventional acupuncturecombined with manipulation in treating youth cervical curvature abnormality patients. Because this novel method can recover the cervical curvature, relieve the neck pain, and improve cervical mobility.

Functionalized three-dimensional graphene sponges for highly efficient crude and diesel oil adsorption.

Modified Hummer's method has been used in this study to synthesize graphene oxide (GO) solution that was utilized for the fabrication of three-dimensional (3D) graphene sponges and their subsequent functionalization through a low-cost and facile vapor-based surface enhancement approach. The functionalized 3D-graphene sponge is an excellent absorbent, which can remove more than 3300 wt.% of crude oil (calculated with respect to the original sorbent mass). The functionalization of the obtained graphene sponges with trichloro (1H,1H,2H,2H-perfluorooctyl)silane enhanced their wettability properties due to the super-hydrophobic nature of the resulting materials characterized by the contact angles in water greater than 150°. Furthermore, their elastic compression modulus (estimated by conducting a series of compression tests) was about 22.3 kPa. The equilibrium modeling of the oil removal process, which was performed by plotting Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms, confirmed the properties of the fabricated 3D graphene sponges as exceptional absorbents for crude and diesel oil, which could be attributed to the oleophilic nature of graphene. Moreover, the obtained 3D graphene sponges could be regenerated via heat treatment, which was conducted to release the adsorbed species. After five adsorption-desorption cycles, the sorption capacity of the produced 3D graphene sponges towards crude oil reached 95% of the initial value.

Nanomaterials for efficiently lowering the freezing point of anti-freeze coolants.

In this paper, we report, for the first time, the effect of the lowered freezing point in a 50% water/50% anti-freeze coolant (PAC) or 50% water/50% ethylene glycol (EG) solution by the addition of carbon nanotubes and other particles. The experimental results indicated that the nano materials are much more efficient (hundreds fold) in lowering the freezing point than the regular ionic materials (e.g., NaCl). The possible explanation for this interesting phenomenon is the colligative property of fluid and relative small size of nano material. It is quite certain that the carbon nanotubes and metal oxide nano particles could be a wonderful candidate for the nano coolant application because they could not only increase the thermal conductivity, but also efficiently lower the freezing point of traditional coolants.

Enhanced Magnetic Properties of Graphene Coated with Fe2O3 Nanoparticles.

Graphene, with its unique 2D nanostructure and excellent electrical, thermal, and mechanical properties, is considered an alternative to carbon nanotubes in nanocomposites. In this study, we present a one step approach for the deposition of iron oxide (Fe2O3) nanoparticles onto graphene sheets through solution mixture. The morphology, crystallinity, and magnetic properties of as-synthesized composites were investigated. It was shown that highly crystalline Fe2O3 nanoparticles were densely and uniformly coated on graphene surface. Magnetic measurements reveal that, as compared to weak diamagnetism of pristine graphene, graphene-Fe2O3 nanocomposites display ferromagnetic behavior with coercivity of 101 Oe, saturation magnetization of 12.6 emu g(-1), and remanent magnetization of 3.13 emu g(-1) at room temperature. The enhanced magnetic performance was attributed to the homogeneous dispersion of Fe2O3 nanoparticles in graphene matrix and such nanocomposites are promising materials for applications in magnetic media and energy storage.

Isolation and characterization of a delta5 FA desaturase from Pythium irregulare by heterologous expression in Saccharomyces cerevisiae and oilseed crops.

By using the polymerase chain reaction approach with two degenerate primers targeting the heme-binding and the third histidine-rich motifs in microsomal carboxyl-directed desaturases, we identified a cDNA PiD5 from Pythium irregulare encoding a delta5 desaturase. The substrate specificity of the enzyme was studied in detail by expressing PiD5 in a yeast (Saccharomyces cerevisiae) mutant strain, AMY-2alpha, where ole1, a delta9 desaturase gene, is disrupted. The result revealed that the encoded enzyme could desaturate unsaturated FA from 16 to 20 carbons beginning with delta9 and delta11 as well as delta8 ethylenic double bonds. Introduction of PiD5 into Brassica juncea under the control of a CaMV 35S constitutive promoter resulted in accumulation of several delta5-unsaturated polymethylene-interrupted FA (delta5-UPIFA) including 18:2-5,9, 18:2-5,11, 18:3-5,9,12, and 18:4-5,9,12,15 in vegetative tissues. The transgenic enzyme could also desaturate the exogenously supplied homo-gamma-linolenic acid (20:3-8,11,14) to arachidonic acid (20:4-5,8,11,14). Introduction of PiD5 into B. juncea and flax under the control of seed-specific promoters resulted in production of delta5-UPIFA, representing more than 10% of the total FA in the seeds.

Carbon-supported molybdenum carbide catalysts for the conversion of vegetable oils.

Ordered mesoporous carbon (OMC)-supported molybdenum carbide catalysts were successfully prepared in one pot using a solvent-evaporation-induced self-assembly strategy accompanied by a carbothermal hydrogen reduction reaction. Characterization with nitrogen sorption, small-angle XRD, and TEM confirmed that the obtained materials had high surface areas, large pore volumes, ordered mesoporous structures, narrow pore size distributions, and uniform dispersions of molybdenum carbide particles. With nitrogen replaced by hydrogen in the carbothermal reduction reaction, the formation temperature of molybdenum carbide could be reduced by more than 100 °C. By changing the amount of molybdenum precursor added from less than 2 % to more than 5 %, molybdenum carbide structures could be easily regulated from Mo(2) C to MoC. The catalytic performance of OMC-supported molybdenum carbide catalysts was evaluated by hydrodeoxygenation of vegetable oils. Compared with Mo(2)C, MoC exhibited high product selectivity and excellent resistance to leaching in the conversion of vegetable oils into diesel-like hydrocarbons.

High-level production of gamma-linolenic acid in Brassica juncea using a delta6 desaturase from Pythium irregulare.

gamma-Linolenic acid (GLA), a nutritionally important fatty acid in mammals, is synthesized by a delta6 desaturase. Here, we report identification of PiD6, a new cDNA from the oleaginous fungus, Pythium irregulare, encoding a 459-amino acid protein that shares sequence similarity to carboxyl-directed desaturases from various species. Expression of PiD6 in yeast (Saccharomyces cerevisiae) revealed that it converts exogenously supplied linoleic acid into GLA, indicating that it encodes a delta6 fatty acid desaturase. Expression of the desaturase in Brassica juncea under the control of the Brassica napus napin promoter resulted in production of three delta6 unsaturated fatty acids (18:2-6, 9; 18:3-6, 9, 12; and 18:4-6, 9, 12, 15) in seeds. Among them, GLA (18:3-6, 9, 12) is the most abundant and accounts for up to 40% of the total seed fatty acids. Lipid class and positional analysis indicated that GLA is almost exclusively incorporated into triacylglycerol (98.5%) with only trace amounts found in the other lipids. Within triacylglycerols, GLA is more abundant at the sn-2 position.