Transfer printing gold nanoparticle arrays by tuning the surface hydrophilicity of thermo-responsive poly N-isopropylacrylamide (pNIPAAm).

For the transfer of 2-D gold nanoparticle arrays between different substrates, we have developed a new method using thermo-responsive poly-N-isopropylacrylamide (pNIPAAm). By tuning the degree of surface hydrophilicity of pNIPAAm between 5 °C and 50 °C, we demonstrate the transfer of arrays extending over micron-scale areas with preservation of array properties.

Effect of post-annealing on the plasma etching of graphene-coated-copper.

High temperature deposition of graphene on Cu by chemical vapor deposition can be used to produce high quality films. However, these films tend to have a non-equilibrium structure, with relatively low graphene adhesion. In this study, samples of graphene grown on copper foils by high temperature CVD were post-deposition annealed at temperatures well below the critical temperature of Cu. Resistance to etching under plasma was examined to assess the mechanical robustness of the graphene on the Cu surface, analyzed using optical and Raman microscopies. We found a correlation between the post-annealing time and etching time for the complete removal of graphene from Cu. Etching rates, minimum etch times, and surface appearance were observed to vary depending on the etching plasma (air, oxygen or nitrogen). Oxygen plasmas were found to be the least aggressive, emphasizing the improved adhesion with post-annealing treatments. Our results imply that the etching of graphene on Cu, and hence the adhesion of graphene, can be controlled by proper annealing and choice of plasma gas.

Copper-phthalocyanine based metal-organic interfaces: the effect of fluorination, the substrate, and its symmetry.

Metal-organic interfaces based on copper-phthalocyanine monolayers are studied in dependence of the metal substrate (Au versus Cu), of its symmetry [hexagonal (111) surfaces versus fourfold (100) surfaces], as well as of the donor or acceptor semiconducting character associated with the nonfluorinated or perfluorinated molecules, respectively. Comparison of the properties of these systematically varied metal-organic interfaces provides new insight into the effect of each of the previously mentioned parameters on the molecule-substrate interactions.

Molecular heterojunction morphology on rough substrate surfaces: component separation by Fourier subtraction.

The study of molecular heterojunction morphology is often complicated by the presence of a topographically complex substrate. On such substrates, it is difficult to definitively assign a topographic feature to a specific component. We propose a technique, based on the separation of features in reciprocal space (Fourier subtraction), to deconvolute a heterojunction surface into two real space images. The technique has been successfully applied to three classes of systems: (1) where the overlayer features are smaller than those of the substrate, such as with small molecule growth on polymer substrates (DIP/PEDOT:PSS); (2) where the overlayer features are larger than the substrate, such as with a polymer film in contact with a corrugated metal surface (P3HT/Al), and (3) where both the overlayer and substrate features are of the same size. The Fourier subtraction method extends the study of morphology to heterojunctions with realistic substrates, where the complex topography may previously have prevented a basic description of the specific features of each component in a heterojunction film.

Validation and quality assurance of planar chromatographic procedures in pharmaceutical analysis.

Within the process of the International Conference on Harmonization (ICH), 2 guidelines were released containing a standardized terminology, a verified model of requirements for the validation of analytical procedures, and some guidance in the practical aspects of conducting validation studies in pharmaceutical analysis. For planar chromatographic procedures, which may be used at different levels either in qualitative identity testing, assays, semiquantitative limit tests, or quantitative determination of impurities, this paper tries to transfer these formal requirements into practical approaches for validation. Basic acceptance criteria for evaluation of validation experiments based on practical experience are proposed. In addition, selected parameters for robustness testing of given procedures and quality assurance of quantitative planar chromatographic testing by control charts is described.

Access of Native Americans to renal transplantation in Arizona and New Mexico.

Lower rates of transplantation among minority groups are a nationally recognized phenomenon. Native Americans (NA) nationally have nearly four times the risk of end-stage renal disease (ESRD) as compared with white (W) Americans and are significantly overrepresented in the Network 15 ESRD population. To understand more about NA and W transplant rates, we looked at all reported Arizona (AZ) and New Mexico (NM) resident cases from the Network No. 15 data base. Age of onset, sex, primary diagnosis, payment source, transplant donor source, and other factors were examined. NA experienced a slightly earlier onset of ESRD than W, and diabetes mellitus was the primary ESRD diagnosis for 63-73% of NA and for 34-39% of W. Because age distribution and frequency of diabetes mellitus of the NA ESRD population differ from those of W in the Network, age-specific and diagnosis-specific transplant rates were examined. Age-adjusted transplant rates per 100 ESRD patients for AZ were 16.4 (NA) and 21.0 (W) and for NM 14.2 (NA) and 22.4 (W). Diagnosis-specific age-adjusted transplant rates for patients with the primary diagnoses of diabetes mellitus and glomerulonephritis, the two most common causes of ESRD among NA, showed a large difference between W and NA rates. Age-adjusted rates for diabetes were: AZ 8.4% (NA) and 14.5% (W); NM 9.8% (NA) and 15.9% (W). Age-adjusted rates for patients with glomerulonephritis were: AZ 23.7% (NA) and 28.0% (W); NM 22.3% (NA) and 33.0% (W). In all comparisons and in both the W and NA ESRD populations, women were transplanted at lower rates than men. NA experienced a greater delay from onset of treated ESRD to transplant than W. Payment source and transplant donor source did not appear to be significantly different between NA and W. The lower transplant rates in NA versus W in Network No. 15 cannot be explained by age- or diagnosis-specific factors.