Controlled microtribology of a metal oxide surface

The rational control of the friction and wear (damage) of engineering, as opposed to model, surfaces under practical conditions such as high contact pressures has long been a technological challenge with much fundamental interest. Lubricant fluids and physisorbed surfactant monolayers (boundary lubricants) are effective friction modifiers but often fail at high loads. We show that the chemisorption of a suitably designed single-chained phosphonate surfactant onto crystalline α-alumina surfaces produces robust protective monolayers that significantly reduce the friction forces and wear even at high loads. The mechanisms are explained, which point to some general principles that offer a basis for scale-up in many different engineering systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Mapping of polished coal surfaces by automated reflectance microscopy

The capabilities of Rapid Scan, a system of automated reflectance microscopy, has been extended to the actual mapping of petrographic variation across polished coal surfaces. This is accomplished through computer control of a microscope stepping stage and the storage of binary reflectance data on disc in a matrix form which permits the proper spatial arrangement of values to be re-created. The maps depict lithotype variation, and the distribution of mineral occurrences, cracks and cleat. An image processor can be employed in further map analysis such as the compilation of reflectance profiles from selected areas.     

Simulation reality and stereotype strength: A problem for equipment designers

In designing human–machine interfaces, it may be necessary for designers to simulate the interface in order to find an acceptable arrangement of controls and displays which have a high expectancy of the relationship between these. We report experiments aimed at determining the level of simulation required to obtain valid measures of stereotype strength relating control movement to display movement. Two experiments are reported, using devices of apparently low and high complexity. Low complexity devices were similar to electronic devices that might be used in the home; the chosen high complexity device was a crane control cabin. For two-dimensional control/display arrangements a low level of simulation generally gave valid results for stereotype strength; a high level of simulation is required for three-dimensional arrangements. With the more complex crane control system, there was a strong effect of the control layout, but little effect of the level of simulation: paper/pencil tests performed as well as computer simulation in giving stereotype strengths. Implications for designers are discussed.     

Current Therapies and Technological Advances in Aqueous Aerosol Drug Delivery

Recent advances in aerosolization technology have led to renewed interest in pulmonary delivery of a variety of drugs. Pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) have experienced success in recent years; however, many limitations are presented by formulation difficulties, inefficient delivery, and complex device designs. Simplification of the formulation process as well as adaptability of new devices has led many in the pharmaceutical industry to reconsider aerosolization in an aqueous carrier. In the acute care setting, breath-enhanced air-jet nebulizers are controlling and minimizing the amount of wasted medication, while producing a high percentage of respirable droplets. Vibrating mesh nebulizers offer advantages in higher respirable fractions (RFs) and slower velocity aerosols when compared with air-jet nebulizers. Vibrating mesh nebulizers incorporating formulation and patient adaptive components provide improvements to continuous nebulization technology by generating aerosol only when it is most likely to reach the deep lung. Novel innovations in generation of liquid aerosols are now being adapted for propellant-free pulmonary drug delivery to achieve unprecedented control over dose delivered and are leading the way for the adaptation of systemic drugs for delivery via the pulmonary route. Devices designed for the metered dose delivery of insulin, morphine, sildenafil, triptans, and various peptides are all currently under investigation for pulmonary delivery to treat nonrespiratory diseases. Although these devices are currently still in clinical testing (with the exception of the Respimat®), metered dose liquid inhalers (MDLIs) have already shown superior outcomes to current pulmonary and systemic delivery methods.     

Recent Developments in Drug Delivery to Prolong Allograft Survival in Lung Transplant Patients

Since the discovery of cyclosporine in 1971, calcineurin inhibitors have played a critical role in the therapeutic suppression of the immune response. Patients receiving solid organ transplants rely heavily on these medications to prevent the acute and chronic rejection of allografted tissue. These therapies can prove difficult because of potential toxicity, heightened risk of invasive infection, and erratic oral bioavailability, requiring frequent blood samples for monitoring of systemic levels. Added challenges are presented in immunosuppression of lung transplant patients owing to the increased susceptibility to invasive infection and extensive immune mechanisms inherent in lung tissue. With the introduction of tacrolimus, a more potent calcineurin inhibitor, clinical outcomes of transplants have continued to improve; however, little improvement has been noted in lung transplantation. While very effective upon arrival at the site of action, tacrolimus and cyclosporine present a variety of formulation challenges such as poor solubility, potential systemic toxicity, and extensive first pass metabolism. Initial attempts to improve solubility in both oral and intravenous formulations have resulted in variable drug absorption and increased systemic toxicity, respectfully, creating a need for formulation improvement. Through alternative routes of delivery and novel formulation techniques, researchers have addressed these issues and, in some cases, demonstrated improved clinical outcomes. Through enhanced solubilization, reduction in absorption variability, and more effective drug targeting with reduced systemic levels, improvements in outcomes and overall patient survival in lung and other solid organ transplantation can be expected.     

Neuroprotective Strategies for Traumatic Brain Injury: Improving Clinical Translation

Traumatic brain injury (TBI) induces secondary biochemical changes that contribute to delayed neuroinflammation, neuronal cell death, and neurological dysfunction. Attenuating such secondary injury has provided the conceptual basis for neuroprotective treatments. Despite strong experimental data, more than 30 clinical trials of neuroprotection in TBI patients have failed. In part, these failures likely reflect methodological differences between the clinical and animal studies, as well as inadequate pre-clinical evaluation and/or trial design problems. However, recent changes in experimental approach and advances in clinical trial methodology have raised the potential for successful clinical translation. Here we critically analyze the current limitations and translational opportunities for developing successful neuroprotective therapies for TBI.