James M. Tour

Bio: James M. Tour is an academic researcher from Rice University. The author has contributed to research in topics: Graphene & Carbon nanotube. The author has an hindex of 143, co-authored 859 publications receiving 91364 citations. Previous affiliations of James M. Tour include Moscow State University & IBM.

Abstract WP253: Increased Hydrogen Sulfide As A New Mechanism For Hyperglycemic Worsening Of Stroke Outcome

Abstract: Introduction: Hyperglycemia at stroke onset worsens outcome and reduces the effectiveness of reperfusion therapies. Increased oxidative and mitochondrial injury likely contribute. To treat this mechanism, we synthesized (PEG)-ylated carbon nanoparticles (CNPs) from acid oxidation of activated charcoal (OAC) generating 3 nm discs, catalytic superoxide dismutase mimetics that protect mitochondrial complexes. Cellular uptake is rapid and delayed I.V. PEG-CNPs are highly protective in reversible MCAO in hyperglycemic rats. Hydrogen sulfide (H 2 S) is an essential gaseous transmitter with a narrow therapeutic index associated with many disorders e.g., diabetes. Its synthesis is influenced by radicals. Excess H 2 S is toxic to mitochondrial complex IV. H 2 S is endogenously oxidized to polysulfides (PS), potent antioxidants also needed for protein persulfidation. We hypothesized that OAC’s favorable redox potential will catalyze H 2 S oxidization to PS, acute hyperglycemia will increase H 2 S and PEG-OACs will blunt the increase. Methods: b.End3 brain endothelial and HEK293 cultured cells were employed. SSP4 fluorescence measured PS levels with increasing concentrations of PEG-OACs. AzMC fluorescence detected H 2 S levels in cells incubated in 100 mg/dL glucose media followed by glucose 500 mg/dL with or without PEG-OACs, first in normoxia followed by anoxia/normoxia. Results: PEG-OACs dose dependently increased cellular PS levels (Fig 1a). High glucose increased H 2 S levels especially during anoxia/normoxia (Fig 1b). PEG-OACs completely eliminated the glucose-induced increase in H 2 S (Fig 1c). Conclusions: Acute hyperglycemia increased H 2 S production especially under conditions mimicking ischemia/reperfusion, an effect eliminated by PEG-OACs. Because of mitochondrial toxicity, an H 2 S increase may contribute to worsened outcome in hyperglycemic stroke. These results suggest a new therapeutic target for this important cause of poor stroke outcome.

Heavy metal removal from coal fly ash for low carbon footprint cement

Abstract: Abstract Development of cementitious materials with low carbon footprint is critical for greenhouse gas mitigation. Coal fly ash (CFA) is an attractive diluent additive in cement due to its widespread availability and ultralow cost, but the heavy metals in CFA could leach out over time. Traditional acid washing processes for heavy metal removal suffer from high chemical consumption and high-volume wastewater streams. Here, we report a rapid and water-free process based on flash Joule heating (FJH) for heavy metals removal from CFA. The FJH process ramps the temperature to ~3000 °C within one second by an electric pulse, enabling the evaporative removal of heavy metals with efficiencies of 70–90% for arsenic, cadmium, cobalt, nickel, and lead. The purified CFA is partially substituted in Portland cement, showing enhanced strength and less heavy metal leakage under acid leaching. Techno-economic analysis shows that the process is energy-efficient with the cost of ~$21 ton −1 in electrical energy. Life cycle analysis reveals the reuse of CFA in cement reduces greenhouse gas emissions by ~30% and heavy metal emissions by ~41%, while the energy consumption is balanced, when compared to landfilling. The FJH strategy also works for decontamination of other industrial wastes such as bauxite residue.

Use of a bioengineered antioxidant in mouse models of metabolic syndrome

Abstract: Background: Oxidative stress has been implicated in metabolic syndrome (MetS); however, antioxidants such as vitamin E have had limited success in the clinic. This prompts the question of what effects amore potent antioxidant might produce. A prime candidate is the recently developed bioengineered antioxidant, poly(ethylene glycol)-functionalizedhydrophilic carbon clusters (PEG-HCCs), which are capable of neutralizing the reactive oxygen species (ROS) superoxide anion and hydroxyl radical at106/molecule of PEG-HCC. In this project, we tested the potential of PEG-HCCs as a possible therapeutic for MetS.Results: PEG-HCC treatment lessened lipid peroxidation, aspartate aminotransferase levels, non-fastingblood glucose levels, and JNK phosphorylation inob/ob mice. PEG-HCC-treated WT mice had an increased response to insulin by insulin tolerance tests and adecrease in blood glucose by glucose tolerance tests. These effects were not observed in HFD-fed mice, regardless of treatment. PEG-HCCs were observed in the interstitial space of liver, spleen, skeletal muscle, and adipose tissue. No significant difference was shown in gluconeogenesis or inflammatory gene expression between treatment and dietary groups.Expert Opinion: PEG-HCCs improved some parameters of disease possibly due to a resulting increase in peripheral insulin sensitivity. However, additional studies are needed to elucidate how PEG-HCCsare producing these effects.

Laser-induced graphene (lig) and laser induced graphene scrolls (ligs) materials

Abstract: Laser-induced graphene (LIG) and laser-induced graphene scrolls (LIGS) materials and, more particularly to LIGS, methods of making LIGS (such as from polyimide (PI)), laser-induced removal of LIG and LIGS, and 3D printing of LIG and LIGS using a laminated object manufacturing (LOM) process.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Graphene: Status and Prospects

Abstract: Graphene is a wonder material with many superlatives to its name. It is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have zero effective mass, and can travel for micrometers without scattering at room temperature. Graphene can sustain current densities six orders of magnitude higher than that of copper, shows record thermal conductivity and stiffness, is impermeable to gases, and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a benchtop experiment. This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.

The chemistry of graphene oxide

Abstract: The chemistry of graphene oxide is discussed in this critical review Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)

Improved Synthesis of Graphene Oxide

Abstract: An improved method for the preparation of graphene oxide (GO) is described. Currently, Hummers’ method (KMnO4, NaNO3, H2SO4) is the most common method used for preparing graphene oxide. We have found that excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. This improved method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or Hummers’ method with additional KMnO4. Moreover, even though the GO produced by our method is more oxidized than that prepared by Hummers’ method, when both are reduced in the same chamber with hydrazine, chemically converted graphene (CCG) produced from this new method is equivalent in its electrical conductivity. In contrast to Hummers’ method, the new method does not generate toxic gas and the temperature is easily controlled. This improved synthesis of GO may be important for large-scale production of GO as well as the ...