The screen printing of a power-law fluid

We present a two-dimensional large-aspect-ratio model for the off-contact screen printing of a power-law fluid. We extend the work of White et al. (J Eng Math 54:49–70, 2005) by explicitly including the fluid/air free surface that is present beneath the screen ahead of the squeegee. In the distinguished parameter limit of greatest interest to industry, the process is quasi-steady on the time-scale of a print and can be analysed in three separate regions using the method of matched asymptotic expansions. This allows us to predict where the fluid transfers through the screen, the point at which it first makes contact with the substrate, and the amount of fluid deposited on the substrate during a print stroke. Finally, we show that using a shear-thinning fluid will decrease the amount of fluid transferred ahead of the squeegee, but increase the amount of fluid deposited on the substrate.     

Cisplatin-loaded porous Si microparticles capped by electroless deposition of platinum

The loading and release of the anti-cancer drug platinum cis-dichlorodiamine (cisplatin) from mesoporous silicon (pSi) microparticles is studied. The pSi microparticles are modified with 1-dodecene or with 1,12-undecylenic acid by hydrosilylation, and each modified pSi material acts as a reducing agent, forming a deposit of Pt on its surface that nucleates further deposition, capping the mesoporous structure and trapping free (unreduced) cisplatin within. Slow oxidation and hydrolytic dissolution of the Si/SiO(2) matrix in buffer solution or in culture medium leads to the release of drugs from the microparticles. The drug-loaded particles show significantly greater toxicity toward human ovarian cancer cells (in vitro), relative to an equivalent quantity of free cisplatin. This result is consistent with the mechanism of drug release, which generates locally high concentrations of the drug in the vicinity of the degrading particles. Control assays with pSi particles loaded in a similar manner with the therapeutically inactive trans isomer of the platinum drug, and with pSi particles containing no drug, result in low cellular toxicity. A hydrophobic pro-drug, cis,trans,cis-[Pt(NH(3))(2)(O(2)C(CH(2))(8)CH(3))(2)Cl(2)], is loaded into the pSi films from chloroform without concomitant reduction of the pSi carrier.     

Direct nn-Scattering Measurement With the Pulsed Reactor YAGUAR

Although crucial for resolving the issue of charge symmetry in the nuclear force, direct measurement of nn-scattering by colliding free neutrons has never been performed. At present the Russian pulsed reactor YAGUAR is the best neutron source for performing such a measurement. It has a through channel where the neutron moderator is installed. The neutrons are counted by a neutron detector located 12 m from the reactor. In preliminary experiments an instantaneous value of 1.1 × 10¹⁸/cm²s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as International Science & Technology Center (ISTC) project No. 2286.     

Influence of doping on the electronic structure of (La,Sr)2CuO4

High-statistics (>4 × 10⁸ counts), room-temperature measurements of the electron-positron momentum density of La_2?x Sr _x CuO₄ have been performed for samples with Sr concentrations of x=0.0, 0.1, 0.13, and 0.2. These spectra have been analyzed in conjunction with theoretical calculations of the electron-positron momentum density. The metallic samples show features consistent with the presence of a Fermi surface, but its evolution with increasing Sr concentration does not follow the predictions of band theory. These results may indicate the effects of electron-electron correlation on the electron momentum distribution in the Cu-O plane.     

New Operating System for Project Management: Consequences and Opportunities

This paper follows “Construction Engineering: Reinvigorating the Discipline.” That paper argued that a new flow-based operating system was poised to replace the activity-centered operating system of traditional project management and that a coherent organizational and contractual approach would evolve. Shifting to a new operating system based on the theory, principles, and practices of production system design will reduce waste, spur learning and innovation, and deliver more value to clients and other participants. After a reflection on a model for making sense, the paper explores the consequences of this shift from a number of perspectives and speculates on the impact on practice and research. The paper closes with a brief reflection on teaching in times of rapid change.     

Glucagon therapy in the treatment of symptomatic bradycardia

Symptomatic bradycardia is commonly seen in the emergency department. Effective drug therapy for this clinical scenario is limited. Although glucagon has been used in no clinical trial in this setting, its cardiac activity may prove useful, particularly in the setting of beta-adrenergic blockade. We report a case series comprising three patients taking maintenance beta-blocker therapy who presented to the ED with symptomatic bradycardia and hypotension and in whom glucagon therapy obviated the need for further treatment. Further study is warranted to evaluate and define the role of glucagon in the treatment of symptomatic bradycardia.