The remarkable electronic and mechanical properties of carbon nanotubes are widely acclaimed, but these molecules also have a unique structure that encapsulates a one-dimensional volume of space. The promise afforded by this structure is often overlooked. Carbon nanotubes have the capability to contain or transport other atoms, molecules, or crystalline materials inside. The constrained lumen of a nanotube could be a novel reaction chamber, catalyzing the synthesis of new compounds by forcing reactants and products to adopt specific conformations. Perhaps most importantly, the intrinsic properties of nanotubes could be modified by filling with species that have opportune magnetic, electronic charge transfer, absorption, mechanical, catalytic, or thermal characteristics. Such nanoscale heterostructures could have broadly tunable properties, but the components are noncovalently associated, so the chemistry and mechanical integrity of the underlying nanotube is preserved. Because of this potential, filling methods are certain to play a critical role in the evolution of carbon nanotubes as engineering materials. Initial efforts to create nanotube heterostructures were focused on filling multiwall carbon nanotubes (MWNTs) with metal salts and low-surface-tension melts by capillarity. However, this approach has proven limited in terms of yield, homogeneity of filling, and the types of materials that can be encapsulated. More recently, the 1998 discovery of a new class of supramolecular materials based on single-wall carbon nanotubes (SWNTs) introduced new methods for efficient filling. The first of these materials, descriptively called a peapod, was a one-dimensional crystal of C 60 molecules assembled inside a SWNT, and was obtained by a vapor phase process. Syntheses of many other peapod materials have been enabled by this discovery. SWNTs have been filled with various fullerenes and metallofullerenes, fullerene adducts, metal complexes, and other small molecules. This growing area of research is rapidly expanding the scope of nanotube-based materials. In this review, we discuss advances in the creation of nanotube heterostructures. Specifically, we will explore the synthesis of these one-dimensional materials and how their structures are manifest in their unique properties. In addition, we will discuss recent advances in the synthesis and characterization of related double-wall carbon nanotube materials. 2748_C003.fm Page 52 Tuesday, March 28, 2006 10:47 AM © 2006 by Taylor & Francis Group, LLC Chapter three: Carbon nanotube peapod materials 53 3.

In previous works, we have shown our discovery of C60@SWNT and first described the general mechanism of filling, which involves the vapor phase transport of C60 molecules to openings in the SWNTs’ walls. Here, we discuss the high-yield synthesis of C60@SWNT by refinements to our method. Yields are measured by a calibrated weight uptake technique, a methodology that is not subject to many of the potential pitfalls inherent to other techniques that have been applied. At certain processing conditions, yields exceeding 90% were obtained and corroborated by transmission electron microscopy. From our data, we determine the parameters most important for creating endohedral SWNT supramolecular assemblies by the vapor phase method. Our results pave the way for successful single-tube measurements and for high-yield filling with non-fullerenes.

In 2000, as part of Tony Blairﾒs promised devolution of British government, an election was held for a newly created political office: The Mayor of Greater London. After being denied the Party nomination, Labour MP Ken Livingstone chose to run as an independent candidate and was expelled from the party. Unencumbered by partisanship and conventional campaign strategy, he ran a nontraditional campaign and presented himself as a political maverick. This strategy proved to be effective as he won a plurality of the vote in a crowded 11 person field. In 2004, Livingstone was re-admitted to the Labour Party and re-elected mayor. In the 2008 election, Livingstone was defeated by an equally unconventional candidate, Conservative MP Boris Johnson. Johnson, who was born in New York City, used many of the same campaign tactics Livingstone employed eight years earlier. Using multivariate analysis, we compare and contrast voting behavior in the 2000 and 2008 Mayoral elections to determine the sources of voter support, the importance of ideology, and the influence of the maverick campaign style.

The effect of combining sub-2 microm porous particles with elevated operating temperatures on chromatographic performance has been investigated in terms of chromatographic efficiency, productivity, peak elution order, and observed operating pressure. The use of elevated temperature in LC does not increase the obtainable performance but allows the same performance to be obtained in less time. Increasing the column temperature did allow the use of longer columns, generating column efficiencies in excess of 100,000 plates and gradient peak capacities approaching 1000. Raising the temperature increased the optimal mobile phase linear velocity, negating somewhat the pressure benefits observed by reducing the solvent viscosity. When operating at higher temperature the analyte retention is not only reduced, but the order of elution will also often change. High temperature separations allowed exotic organic modifiers such as isopropanol to be exploited for alternative selectivity and faster analysis. Finally, care must be taken when using high temperature separations to ensure that the narrow peak widths produced do not compromise the quality of data obtained from detectors such as high resolution mass spectrometers.

The metabonomic effects of hepatotoxic doses of pravastatin on the urinary metabolic profiles of female rats have been investigated using ultra performance liquid chromatography (UPLC)-oa-TOF-MS and, independently, by (1)H NMR spectroscopy. UPLC was performed using a 1 mm microbore column packed with 1.7 microm particles. Examination of the data obtained from the individual animals, aided by statistical interpretation of the data, made it possible to identify potential markers for toxicological effects, with both NMR and UPLC-MS analysis highlighting distinct changes in the urinary metabolite profiles. These markers, which included elevated taurine and creatine, as well as bile acids, were consistent with hepatotoxicity in some animals, and this hypothesis was supported by histopathological and clinical chemistry findings. The analytical data from both techniques could be used to define a metabolic "trajectory" as toxicity developed and to provide an explanation for the lack of hepatotoxicity for one of the animals. The two analytical approaches (UPLC-MS and NMR) were found to be complementary whilst the use of a 1mm i.d. x 100 mm column reduced the amount of sample required for analysis to 2 microL, compared with 10 microL for a 2.1mm i.d. x 100 mm column. The 1mm i.d. column also provided increased signal-to-noise without loss of chromatographic efficiency.

The use of a combination of ultraperformance liquid chromatography at approximately 11,000 psi on sub 2-microm particles combined with reversed-phase gradient chromatography at a temperature of 90 degrees C is described as applied to the analysis of endogenous and drug metabolites in human and animal urine. By using elevated temperatures, back pressures can be reduced while maintaining high flow rates and chromatographic efficiency, with peaks 1-3 s wide at the base. Application to urine samples provided a peak capacity of approximately 700 for a 10-min analysis and greater than approximately 1000 in 1 h. Despite the narrow nature of the peaks, good quality mass spectra were also obtained, allowing the identification of typical drug and endogenous metabolites. These ultra-high-resolution chromatograms should be ideal for the analysis of complex samples in, for example, metabolite identification, impurity identification, and metabonomic/metabolomic studies. Applications in natural product analysis and proteomics can also be envisaged.

A quantitative Ultra Performance liquid chromatography/tandem mass spectrometry (UPL/MS/MS) protocol was developed for a five-compound mixture in rat plasma. A similar high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) quantification protocol was developed for comparison purposes. Among the five test compounds, three preferred positive electrospray ionization (ESI) and two preferred negative ESI. As a result, both UPLC/MS/MS and HPLC/MS/MS analyses were performed by having the mass spectrometer collecting ESI multiple reaction monitoring (MRM) data in both positive and negative ion modes during a single injection. Peak widths for most standards were 4.8 s for the HPLC analysis and 2.4 s for the UPLC analysis. There were 17 to 20 data points obtained for each of the LC peaks. Compared with the HPLC/MS/MS method, the UPLC/MS/MS method offered 3-fold decrease in retention time, up to 10-fold increase in detected peak height, with 2-fold decrease in peak width. Limits of quantification (LOQs) for both HPLC and UPLC methods were evaluated. For UPLC/MS/MS analysis, a linear range up to four orders of magnitude was obtained with r2 values ranging from 0.991 to 0.998. The LOQs for the five analytes ranged from 0.08 to 9.85 ng/mL. Three levels of quality control (QC) samples were analyzed. For the UPLC/MS/MS protocol, the percent relative standard deviation (RSD%) for low QC (2 ng/mL) ranged from 3.42 to 8.67% (N = 18). The carryover of the UPLC/MS/MS protocol was negligible and the robustness of the UPLC/MS/MS system was evaluated with up to 963 QC injections.

A new approach to obtain fragmentation information in liquid chromatography/mass spectrometry (LC/MS) studies of small molecules in complex mixtures is presented using simultaneous acquisition of exact mass at high and low collision energy, MS(E). LC/MS-TOF and LC/MS/MS-TOF are powerful tools for the analysis of complex mixtures, especially those for biological fluids allowing the elucidation of elemental composition and fragmentation information. In this example the composition of rat urine was studied using this new approach, allowing the structures of several endogenous components to be confirmed in one analytical run by the simultaneous acquisition of exact mass precursor and fragment ion data. The spectral data obtained using this new approach are comparable to those obtained by conventional LC/MS/MS as exemplified by the identification of endogenous metabolites present in rat urine.

Broad, bipartisan support for environmental protection in the 1960s eroded in subsequent decades as environmental issues became more polarized, particularly along party lines with Democrats lending greater support to environmental causes than Republicans. Yet, party differences and the general influence of partisanship on member behavior may vary over time as changes occur in Congress. Specifically, this article posits that the Republican takeover of the House and Senate in the 1994 elections and the accompanying increase of power vested in leaders enhanced the significance of partisanship. Using League of Conservation Voters’ scores for members of both the House of Representatives and the Senate for the years 1993–2002, this article examines the role of partisanship and other factors on environmental support. While this article confirms the enduring importance of partisanship, we found that both partisanship and other determinants, like constituency characteristics, of members’ support for the environment exhibit considerable variation. This article concludes by suggesting that future research should examine the sources of this variation.

To date, the sizes of the nanoscale ionic aggregates present in ionomers as determined by scanning transmission electron microscopy (STEM) experiments are inconsistent with small-angle X-ray scattering (SAXS) data interpreted by the Yarusso-Cooper model. To address this discrepancy, we have investigated a pair of model nanoparticles (11- and 55-atom An clusters) with both STEM and SAXS. To mimic ionic aggregates, these nanoparticles were supported by amorphous PS films of predetermined thickness. While the size of the STEM probe was inconsequential to the resolution and measurement of the particles, the optimal specimen thickness was determined to be less than 50 nm. SAXS was performed on dilute solutions of the nanoparticles and fit using a monodisperse, noninteracting hard-sphere form factor model. For Au 11, STEM finds a diameter of 1.3 +/- 0.14 nm and SAXS finds a diameter of 1.4 nm. Similarly, both STEM and SAXS determine a diameter of 1.7 nm for Au 55. For a combined system of An 11 and Au 55, STEM data suggests a bimodal distribution of particle sizes consistent with those of the individual particles while SAXS data indicate hard spheres with diameter of 1.6 nm. Analysis of this model system has allowed us to optimize several experimental conditions of potential importance in reconciling STEM and SAXS data from ionomers.

The combination of a new 1.7 mum reversed-phase packing material, and a chromatographic system, operating at ca. 12,000 psi, (so-called ultra performance liquid chromatography, UPLC) has enabled dramatic increases in chromatographic performance to be obtained for complex mixture separation. This increase in performance is manifested in improved peak resolution, together with increased speed and sensitivity. Here, we show that UPLC offers significant advantages over conventional reversed-phase HPLC amounting to a more than doubling of peak capacity, an almost 10-fold increase in speed and a 3- to 5-fold increase in sensitivity compared to that generated with a conventional 3.5 microm stationary phase. The first functional genomic application of UPLC-MS technology is illustrated here with respect to multivariate metabolic profiling of urines from males and females of two groups of phenotypically normal mouse strains (C57BL19J and Alpk:ApfCD) and a "nude mouse" strain. We have also compared this technology to conventional HPLC-MS under similar analytical conditions and show improved phenotypic classification capability of UPLC-MS analysis together with increased ability to probe differential pathway activities between strains as a result of improved analytical sensitivity and resolution.

The use of Ultra Performance Liquid Chromatography (UPLC), with a rapid 1.5 minute reversed-phase gradient separation on a 1.7 mu m reversed-phase packing material to provide rapid "high throughput" support for metabonomic screening is demonstrated. The peak capacity and the number of marker ions detected using these fast UPLC separations and oa-TOF MS was found to be similar to that generated by conventional HPLC-MS methods with a 10 minute separation. The UPLC-MS methodology was applied to the analysis of urine samples from rodents, including normal and Zucker obese rats and three strains of mice (of both sexes), and was found to provide rapid discrimination between age, strain, gender and diurnal variation.

. Single wall carbon nanotubes filled with C 60 were analyzed using resonance Raman scattering and electron energy loss spectroscopy. In order to obtain concentrations of the fullerene molecules inside the tubes, the scattering intensity from the fullerenes relative to that from the tubes was used. Since the scattering intensity from the tubes is subject to strong fluctuations, the determination of the concentrations is shown to require averaging of results from different lasers and from all observable Raman lines. The fluctuations are shown to be intrinsic and a consequence of photoselective resonance scattering. Calibration of absolute concentrations can be obtained from electron energy loss spectroscopy performed on the same samples. Samples with three different diameters were analyzed and good agreement between the fullerene concentrations measured by the two methods was obtained.

Artificial burrow systems (ABS) have been used to manage populations of the western burrowing owl (Athene cunicularia hypugaea), study their breeding biology, and prevent construction impacts or mitigate habitat loss. However, few studies have documented rates of ABS reoccupancy or longevity. We examined patterns of ABS use by western burrowing owls in southwestern Idaho from 1997-2001 by establishing 104 clusters (2 or 3 ABS per cluster). Eighty of these clusters were both available and monitored for greater than or equal to4 years. Annual occupancy rate for the 80 clusters averaged 55.4+/-4.3% (SE), and reoccupancy rate was higher than other studies reported for owls nesting in natural burrows. Twenty-six of 80 (32.5%) clusters were used greater than or equal to4 years, and of these, owls nested in 14 clusters every year they were available. Our results indicate that artificial burrows provided long-term nest sites for burrowing owls, which has important implications for management and future conservation of this species.