Jonathan Coleman

The search for high capacity, low-cost electrode materials for sodium-ion batteries is a significant challenge in energy research. Among the many potential candidates, layered compounds such as MoS2 have attracted increasing attention. However, such materials have not yet fulfilled their true potential. Here we show that networks of liquid phase exfoliated MoS2 nanosheets, reinforced with 20 wt%, single-wall carbon nanotubes, can be formed into sodium-ion battery electrodes with large gravimetric, volumetric and areal capacity. The MoS2/nanotube composite films are highly porous, electrically conductive and mechanically robust due to the percolating carbon nanotube network. When directly employed as the working electrode, they exhibit specific capacity of >400 mAh/g and volumetric capacity of ~650 mAh/cm. Their mechanical stability allows them to be processed into free-standing films with tunable thickness of up to ~100 μm, corresponding to an areal loading of 15 mg/cm. Their hig...

Treatment paradigms for patients with upper tract urothelial carcinoma (UTUC) are typically extrapolated from studies of bladder cancer despite their distinct clinical and molecular characteristics. The advancement of UTUC research is hampered by the lack of disease-specific models. Here, we report the establishment of patient derived xenograft (PDX) and cell line models that reflect the genomic and biological heterogeneity of the human disease. Models demonstrate high genomic concordance with the corresponding patient tumors, with invasive tumors more likely to successfully engraft. Treatment of PDX models with chemotherapy recapitulates responses observed in patients. Analysis of a HER2 S310F-mutant PDX suggests that an antibody drug conjugate targeting HER2 would have superior efficacy versus selective HER2 kinase inhibitors. In sum, the biological and phenotypic concordance between patient and PDXs suggest that these models could facilitate studies of intrinsic and acquired resi...

The engraftment of human tumor tissues into immunodeficient host mice to generate patient-derived xenograft (PDX) models has become increasingly utilized for many types of cancers. By capturing the unique genomic and molecular properties of the parental tumor, PDX models enable analysis of patient-specific clinical responses. PDX models are an important platform to address the contribution of inter-tumoral heterogeneity to therapeutic sensitivity, tumor evolution, and the mechanisms of treatment resistance. With the increasingly important role played by targeted therapies in urological malignancies, the establishment of representative PDX models can contribute to improved facilitation and adoption of precision medicine. In this review of the evolving role of the PDX in urothelial cancer and kidney cancer, we discuss the essential elements of successful graft development, effective translational application, and future directions for clinical models.

To understand the longitudinal renal function trends in patients undergoing radical nephroureterectomy (RNU) and identify clinicopathologic characteristics associated with estimated glomerular filtration rate (eGFR) recovery. 147 patients were available for analysis. Longitudinal eGFR trends were assessed by plotting each patient's eGFR measurements over time. The patient population was dichotomized using eGFR < 60 ml/min/1.73 m2 versus ≥ 60 ml/min/1.73 m2. Cumulative incidence and competing risk regression analysis were used to estimate recovery of postoperative eGFR to the preoperative level and identify clinicopathologic characteristics associated with eGFR recovery. Median age was 68.7 years and median preoperative eGFR was 55.9 ml/min/1.73 m2. 63.6% were male and 95.8% were white. The cumulative incidence of eGFR recovery was significantly higher in patients with baseline eGFR < 60 ml/min/1.73 m2 compared to those with baseline eGFR ≥ 60 ml/min/1.73 m2 (p = 0.01), wit...

To examine the mode of relapse detection and subsequent treatment after partial or radical nephrectomy in patients with low-risk (pT1, N0, Nx) kidney cancer. Retrospective study on 1404 patients treated with partial or radical nephrectomy for low-risk kidney cancer from the years 2000-2012. Scans for chest imaging (X-ray or CT) and abdominal imaging (CT, MRI, or ultrasound) are tabulated. For those patients with relapse, the site, mode of detection, and symptoms were recorded. Twenty-one patients relapsed with a median follow-up of 4.1 years for patients who did not relapse. In 17 (81 %) patients, relapse was detected by imaging alone, while 4 (19 %) patients presented with symptoms. Of the patients who relapsed by imaging, 13 (76 %) were treated immediately, while 4 (24 %) continued observation. During the first 3 years of follow-up, 5762 imaging studies were performed to detect 8 relapses, with 6 patients receiving immediate treatment. The median number of imaging studies per patient per year for the first 3 years was 1.7 (interquartile range 1.0, 2.3) including 30 % CT, 3 % MRI, 36 % X-ray, and 31 % ultrasounds. We found a low yield of surveillance imaging in the first 3 years for pT1 kidney cancer. Nearly 1000 imaging studies were performed to detect one relapse that required treatment. Further studies are needed to evaluate the clinical impact of imaging surveillance according to recent guidelines.

Experimental measurements of optical limiting of nanosecond laser pulses by two distinctly different polymer and carbon nanostructure composite materials dispersed in solution is reported here. The polymer poly(para-phenylenevinylene-co-2,5-dioctyloxy-meta-phenylenevinylene) was used to form exclusive multi walled carbon nanotube and polymer composites. The polymer poly(9,9-di-n-octylfluorenyl-2,7-diyl) was used to form composites consisting of multi walled carbon nanotubes, other clearly defined carbon nanoparticles and

Cell line models aid in understanding cancer aggressiveness. The aim of this study was the establishment of a metastatic variant (T24M) of the T24 bladder cancer cell line and its initial characterization at chromosomal and proteomic levels. T24M were spontaneously developed in mice from T24 cells, following cycles of subcutaneous injections and culture in vitro. Transwell migration assays and injections in mice revealed increased migration and tumorigenic properties of T24M compared to the T24 cells. Cytogenetic analysis demonstrated that T24M retained several karyotypic characteristics of the parental cells and also acquired novel chromosomal aberrations related to aggressive bladder cancer. Proteomic analysis of the T24 and T24M cells by 2-DE and MS led to the generation of their 2-DE proteomic map and revealed differences in multiple proteins. These include proteases of the lysosomal and proteasome degradation pathways, mitochondrial and cytoskeletal proteins. The 2-DE findings were confirmed by immunoblotting of cell lysates and immunohistochemistry of bladder cancer tissue sections for cathepsin D and activity assays for proteasome. Collectively, our results suggest that the T24M cells reflect many known chromosomal and proteomic aberrations encountered in aggressive bladder cancers but also provide access to novel findings with potentially clinical applications.

[*] Dr. S. Collins, Dr. M. Kozlov, J. Razal, Dr. VH Ebron, M. Selvidge, Prof. JP Ferraris, Prof. RH Baughman The NanoTech Institute and Department of Chemistry The University of Texas at Dallas PO Box 830688, BE26 Richardson, TX 75083-0688, USA E-mail: ...

Single walled nanotubes are difficult to disperse in solvents, with dispersion quality limited by nanotube bundling at high concentration. We quantitatively study dispersions of singlewall nanotubes, functionalized with the bulky molecules PABS, PEG, and ODA, in common ...

Purpose: To evaluate a surface conductive radiofrequency (RF) coagulation instrument (Tissuelink FB3.0) in laparoscopic and open partial nephrectomy (PN) in hereditary kidney cancer. The lesion depth and viability in the pathologic specimens from a surgical series and an acute ...

We demonstrate a water-based method to prepare transparent, conducting graphene/single-walled nanotube hybrid films. While the transmittance decreases slightly with increasing graphene content, the DC conductivity, sigma(DC), and sheet resistance scale non-monotonically with film composition. We observe an optimum composition of approximately 3 wt % graphene, which results in a peak in the DC conductivity. We have calculated the figure of merit, the DC to optical conductivity ratio, sigmaDC/sigmaOp, which also shows a peak at this composition. We find that this effect is only present for small graphene flakes. In addition, acid treatment increases both the sigmaDC and sigmaDC/sigmaOp by x2.5. Interestingly, acid treatment is more effective for films close to the optimum composition. This has the effect of sharpening the peaks in both sigmaDC and sigmaDC/sigmaOp. For acid-treated films, addition of 3 wt % graphene results in a 40% increase in sigmaDC/sigmaOp compared to the nanotube-only film, from 12.5 to 18. Optimized, acid-treated films display transmittance of 80% coupled with a sheet resistance of 100 Omega/[square].

We have measured the dispersibility of single-walled carbon nanotubes in a range of solvents, observing values as high as 3.5 mg/mL. By plotting the nanotube dispersibility as a function of the Hansen solubility parameters of the solvents, we have confirmed that successful solvents occupy a well-defined range of Hansen parameter space. The level of dispersibility is more sensitive to the dispersive Hansen parameter than the polar or H-bonding Hansen parameter. We estimate the dispersion, polar, and hydrogen bonding Hansen parameter for the nanotubes to be <delta(D)> = 17.8 MPa(1/2), <delta(P)> = 7.5 MPa(1/2), and <delta(H)> = 7.6 MPa(1/2). We find that the nanotube dispersibility in good solvents decays smoothly with the distance in Hansen space from solvent to nanotube solubility parameters. Finally, we propose that neither Hildebrand nor Hansen solubility parameters are fundamental quantities when it comes to nanotube-solvent interactions. We show that the previously calculated dependence of nanotube Hildebrand parameter on nanotube diameter can be reproduced by deriving a simple expression based on the nanotube surface energy. We show that solubility parameters based on surface energy give equivalent results to Hansen solubility parameters. However, we note…

A method is presented to produce graphene dispersions, stabilized in water by the surfactant sodium cholate, at concentrations up to 0.3 mg/mL. The process uses low power sonication for long times (up to 400 h) followed by centrifugation to yield stable dispersions. The dispersed concentration increases with sonication time while the best quality dispersions are obtained for centrifugation rates between 500 and 2000 rpm. Detailed TEM analysis shows the flakes to consist of 1-10 stacked monolayers with up to 20% of flakes containing just one layer. The average flake consists of approximately 4 stacked monolayers and has length and width of approximately 1 mum and approximately 400 nm, respectively. These dimensions are surprisingly stable under prolonged sonication. However, the mean flake length falls from approximately 1 mum to approximately 500 nm as the centrifugation rate is increased from 500 to 5000 rpm. Raman spectroscopy shows the flake bodies to be relatively defect-free for centrifugation rates below 2000 rpm. The dispersions can be easily cast into high-quality, free-standing films. The method extends the scope for scalable liquid-phase processing of graphene for a wide range of applications.

Single-wall carbon nanotubes (SWCNT) are severely restricted in their applications, as they exist in rope-like bundles. Recently, J. Coleman et al. demonstrated a spectroscopic method to monitor bundle dissociation in low concentration NT-polymer composites.1 The method ...

The optical properties of high-concentration solutions of conjugated molecules are dominated by inner-filter and re-absorption effects. We apply a simple model to isolate the contributions from these phenomena to the non-linearity of the observed photoluminescence (PL) intensity with concentration. Poly (9, 9-dioctylflourene)(PFO) solutions were studied across a range of concentrations and in a number of different solvents. The model accurately predicts the behaviour of PFO in good solvents up to concentrations above 0.1 mg/ml. In ...

Applications of single-wall carbon nanotubes (SWNT) are severely restricted, as they exist in rope-like bundles. Many methods have been suggested to de-bundle SWNTs, including both covalent and non-covalent funtionalisation with surfactants, acids, polymers and macromolecules. However, these strategies are unsatisfactory because they result in either the chemical modification of the nanotube or the presence of residual dispersion agents. What is required is the demonstration of stable, exfoliated SWNT dispersions in ...

The single most common processing technique for carbon nanotubes involves dispersing them in liquid media.[1] The resulting suspensions can then be used for fundamental studies of the properties of the nanotubes themselves [2] or can be further processed into useful structures such as sheets [3] or fibers.[4] This procedure has been incredibly successful in spite of one huge obstacle: owing to their high molecular weight, nanotubes are considered insoluble in all known solvents. This handicap has generally been circumvented by ...

Large-scale debundling of single-walled nanotubes has been demonstrated by dilution of nanotube dispersions in the solvent N-methyl-2-pyrrolidone (NMP). At high concentrations some very large (~ 100s of micrometers) nanotube aggregates exist that can be removed by mild centrifugation. By measurement of the absorbance before and after centrifugation as a function of concentration the relative aggregate and dispersed nanotube concentrations can be monitored. No aggregates are observed below C NT≈ 0.02 mg/mL, suggesting that ...