The dedicated high‐resolution grazing‐incidence X‐ray scattering beamline 8‐ID‐E at the Advanced Photon Source

As an increasingly important structural‐characterization technique, grazing‐incidence X‐ray scattering (GIXS) has found wide applications for in situ and real‐time studies of nanostructures and nanocomposites at surfaces and interfaces. A dedicated beamline has been designed, constructed and optimized at beamline 8‐ID‐E at the Advanced Photon Source for high‐resolution and coherent GIXS experiments. The effectiveness and applicability of the beamline and the scattering techniques have been demonstrated by a host of experiments including reflectivity, grazing‐incidence static and kinetic scattering, and coherent surface X‐ray photon correlation spectroscopy. The applicable systems that can be studied at 8‐ID‐E include liquid surfaces and nanostructured thin films.     

Relationship between structural and stress relaxation in a block-copolymer melt

The relationship between structural relaxation on molecular length scales and macroscopic stress relaxation was explored in a disordered block-copolymer melt. Experiments show that the structural relaxation time, measured by x-ray photon correlation spectroscopy is larger than the terminal stress relaxation time, measured by rheology, by factors as large as 100. We demonstrate that the structural relaxation data are dominated by the diffusion of intact micelles while the stress relaxation data are dominated by contributions due to disordered concentration fluctuations.     

Conversion of norbornene derivatives into vicinal-dithioethers via S8 activation

Norbornene reacts with elemental sulfur to give a mixture of trithiolane and pentathiepane. Sulfuration of norbornene derivatives was achieved with elemental sulfur, by using a catalytic amount of a nickel complex, to afford selectively the corresponding trithiolanes. The most effective catalytic system was Ni(NH₃)₆Cl₂ in dimethylformamide. The trithiolanes were reduced with super-hydride into 1,2-dithiolate salts, and quenched in situ to form vicinal-dithioethers.     

Identification of EZH2 and EZH1 Small Molecule Inhibitors with Selective Impact on Diffuse Large B Cell Lymphoma Cell Growth

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Properties of ionic liquids on Au surfaces: non-conventional anion exchange reactions with carbonate

A simple anion metathesis in diluted aqueous carbonate at room temperature affords 1-(12-mercaptododecyl)-3-methyl-imidazolium carbonate (MDMI-HCO(3)) from MDMI salts self-assembled on gold films and nanoparticles. The properties of MDMI-SAM differ from MDMI in solution, for which the anion exchange reaction does not proceed.     

Potential interaction between the volatile and non-volatile fractions on the in vitro antimicrobial activity of three South African Pelargonium (Geraniaceae) species

Previous studies have reported promising antimicrobial efficacy for the essential oils and solvent extracts of several indigenous Pelargonium species. This study aimed to determine if any pharmacological interaction (e.g. synergism or antagonism) exists between the volatile and non-volatile components when the different fractions were investigated. The antimicrobial activity of the following fractions were tested; the essential oil prepared by hydrodistillation (EO), non-volatile fraction (NV), prepared by extraction of plant material remaining in the distilling apparatus (having no or negligible volatile constituents) and solvent extracts prepared from fresh (FC) and dried (DC) plant material containing both volatile and non-volatile constituents. Pelargonium quercifolium oil was dominated by p-cymene (42.1%) and viridiflorol (16.9%), while P. graveolens and P. tomentosum oil had high levels of isomenthone (84.0 and 58.8%, respectively). Menthone was noted as a major constituent in the P. tomentosum EO sample. It was evident from the results that the presence of volatile constituents in the three species; P. graveolens, P. quercifolium and P. tomentosum is generally not a pre-requisite for antimicrobial activity. The most significant variations of antimicrobial activity were noted for P. tomentosum where poorer activity was noted for the FC and EO fractions against Bacillus cereus and Candida albicans. Studies on Staphylococcus aureus, however, showed the converse, where best activity was noted for the FC fraction (3.0 mg/mL). For P. quercifolium, the DC fraction indicated a notable increase in anti-staphylococcal activity (2.0 mg/mL) when compared with the FC (8.0 mg/mL) and EO (16.0 mg/mL) fractions. For P. tomentosum, the FC fraction indicated much lower antimicrobial activity (against both B. cereus and C. albicans) when compared with all other fractions, suggesting that the essential oils may impact negatively on the antimicrobial activity when tested against these two pathogens.     

Process analytical technology for chromatography

A major United States Food and Drug Administration effort is devoted to process analytical technology (PAT), which is emerging as the likely "surprise" of the second half of the decade. PAT is an approach to monitoring, manufacturing, and other processes on a continuous rather than discrete basis. It carries the future promise of new methods of production. Building PAT into a chromatography system provides a significant cost and quality advantage to high volume multitest laboratories and provides a significant marketing advantage to the first suppliers able to implement such an approach.     

How a liquid becomes a glass both on cooling and on heating

The onset of structural arrest and glass formation in a concentrated suspension of silica nanoparticles in a water-lutidine binary mixture near its consolute point is studied by exploiting the near-critical fluid degrees of freedom to control the strength of an attraction between particles and multispeckle x-ray photon correlation spectroscopy to determine the particles' collective dynamics. This model system undergoes a glass transition both on cooling and on heating, and the intermediate liquid realizes unusual logarithmic relaxations. How vitrification occurs for the two different glass transitions is characterized in detail and comparisons are drawn to recent theoretical predictions for glass formation in systems with attractive interactions.     

Comprehensive quality control programme for serology and nucleic acid testing using an Internet-based application

The National Serology Reference Laboratory, Australia (NRL) has quality assured the serology for high risk blood-borne infections since 1985, commencing with anti-Human Immunodeficiency Virus (HIV) enzyme immunoassays and later extending the programmes to other blood-borne virus testing and to nucleic acid testing. A quality control (QC) programme was considered the most appropriate manner in which to achieve real-time monitoring. An Internet-based application, EDCNet, facilitates the entry of results of QC sample testing and returns the analysed results instantaneously. Results can be displayed in a variety of tables and charts, so that QC results from blood service and diagnostic laboratories can be monitored. Comparison of results between laboratories using the same system offers monitoring of accuracy, while within-laboratory comparisons offer monitoring of the assay precision. More than 200,000 data points were submitted to EDCNet in 2002 from blood service laboratories as well as from diagnostic laboratories. Analysis of reagent batch variability was determined, e.g. the coefficient of variation between batches of seven assays used to detect anti-hepatitis C virus (HCV) antibodies ranged from 4.9% to 21.6%. Using EDCNet, laboratories can monitor both precision and accuracy of results by comparison with the results of other laboratories. The system may be a highly cost-effective method for maintaining quality.