Graphene-polyelectrolyte multilayer membranes with tunable structure and internal charge

One great advantage of graphene-polyelectrolyte multilayer (GPM) membranes is their tunable structure and internal charge for improved separation performance. In this study, we synthesized GO-dominant GPM membrane with internal negatively-charged domains, polyethyleneimine (PEI)-dominant GPM membrane with internal positively-charged domains and charge-balanced dense/loose GPM membranes by simply adjusting the ionic strength and pH of the GO and PEI solutions used in layer-by-layer membrane synthesis. A combined system of quartz crystal microbalance with dissipation (QCM-D) and ellipsometry was used to analyze the mass deposition, film thickness, and layer density of the GPM membranes. The performance of the GPM membranes were compared in terms of both permeability and selectivity to determine the optimal membrane structure and synthesis strategy. One effective strategy to improve the GPM membrane permeability-selectivity tradeoff is to assemble charge-balanced dense membranes under weak electrostatic interactions. This balanced membrane exhibits the highest MgCl2 selectivity (∼86%). Another effective strategy for improved cation removal is to create PEI-dominant membranes that provide internal positively-charged barrier to enhance cation selectivity without sacrificing water permeability. These findings shine lights on the development of a systematic approach to push the boundary of permeability-selectivity tradeoff for GPM membranes

Sub-nanosecond signal propagation in anisotropy engineered nanomagnetic logic chains

Energy efficient nanomagnetic logic (NML) computing architectures propagate and process binary information by relying on dipolar field coupling to reorient closely-spaced nanoscale magnets. Signal propagation in nanomagnet chains of various sizes, shapes, and magnetic orientations has been previously characterized by static magnetic imaging experiments with low-speed adiabatic operation; however the mechanisms which determine the final state and their reproducibility over millions of cycles in high-speed operation (sub-ns time scale) have yet to be experimentally investigated. Monitoring NML operation at its ultimate intrinsic speed reveals features undetectable by conventional static imaging including individual nanomagnetic switching events and systematic error nucleation during signal propagation. Here, we present a new study of NML operation in a high speed regime at fast repetition rates. We perform direct imaging of digital signal propagation in permalloy nanomagnet chains with varying degrees of shape-engineered biaxial anisotropy using full-field magnetic soft x-ray transmission microscopy after applying single nanosecond magnetic field pulses. Further, we use time-resolved magnetic photo-emission electron microscopy to evaluate the sub-nanosecond dipolar coupling signal propagation dynamics in optimized chains with 100 ps time resolution as they are cycled with nanosecond field pulses at a rate of 3 MHz. An intrinsic switching time of 100 ps per magnet is observed. These experiments, and accompanying macro-spin and micromagnetic simulations, reveal the underlying physics of NML architectures repetitively operated on nanosecond timescales and identify relevant engineering parameters to optimize performance and reliability.Comment: Main article (22 pages, 4 figures), Supplementary info (11 pages, 5 sections

Establishing an experimental rat model of photodynamically-induced retinal vein occlusion using erythrosin B

<b>AIM:</b>To develop a reliable, reproducible rat model of retinal vein occlusion (RVO) with a novel photosensitizer (erythrosin B) and study the cellular responses in the retina.<b>METHODS</b>:Central and branch RVOs were created in adult male rats <i>via</i> photochemically-induced ischemia. Retinal changes were monitored<i> via</i> color fundus photography and fluorescein angiography at 1 and 3h, and 1, 4, 7, 14, and 21d after irradiation. Tissue slices were evaluated histopathologically. Retinal ganglion cell survival at different times after RVO induction was quantified by nuclear density count. Retinal thickness was also observed.<b>RESULTS</b>:For all rats in both the central and branch RVO groups, blood flow ceased immediately after laser irradiation and retinal edema was evident at one hour. The retinal detachment rate was 100% at 3h and developed into bullous retinal detachment within 24h. Retinal hemorrhages were not observed until 24h. Clearance of the occluded veins at 7d was observed by fluorescein angiography. Disease manifestation in the central RVO eyes was more severe than in the branch RVO group. A remarkable reduction in the ganglion cell count and retinal thickness was observed in the central RVO group by 21d, whereas moderate changes occurred in the branch RVO group.<b>CONCLUSION:</b> Rat RVO created by photochemically-induced ischemia using erythrosin B is a reproducible and reliable animal model for mimicking the key features of human RVO. However, considering the 100% rate of retinal detachment, this animal model is more suitable for studying RVO with chronic retinal detachment

How New Chinese Immersion School Teachers Can Improve Their Teaching Skills And Have A Mindset Of Supporting And Inspiring Students?

The research question in this article is to find out how new Chinese immersion school teachers can improve their teaching skills and have a mindset of supporting and inspiring students. The project consists of a literature review and a website. Based on large amount of literature review and intensive research, conclusion have been drawn to answer the research question, The research conclusions are presented in a well-designed website aiming to help new teachers who are in transition to teach in Chinese immersion school in U.S. The findings are combined into four representative aspects: social ideologies, patterns of teacher-student interaction, classroom roles, teaching and learning. In the expansive discussion through these four aspects, the research question is addressed with the support of practical classroom cases, in- depth analysis and recommendation. This research not only answers the research question from an academic perspective but also aims to help new Chinese immersion school teachers to solve their struggles and problems in transition

Simple Metals at High Pressure

In this lecture we review high-pressure phase transition sequences exhibited by simple elements, looking at the examples of the main group I, II, IV, V, and VI elements. General trends are established by analyzing the changes in coordination number on compression. Experimentally found phase transitions and crystal structures are discussed with a brief description of the present theoretical picture.Comment: 22 pages, 4 figures, lecture notes for the lecture given at the Erice course on High-Pressure Crystallography in June 2009, Sicily, Ital

The therapeutic potential of the filarial nematode-derived immunodulator, ES-62 in inflammatory disease

The dramatic recent rise in the incidence of allergic or autoimmune inflammatory diseases in the West has been proposed to reflect the lack of appropriate priming of the immune response by infectious agents such as parasitic worms during childhood. Consistent with this, there is increasing evidence supporting an inverse relationship between worm infection and T helper type 1/17 (Th1/17)-based inflammatory disorders such as rheumatoid arthritis, inflammatory bowel disease, type 1 diabetes and multiple sclerosis. Perhaps more surprisingly, given that such worms often induce strong Th2-type immune responses, there also appears to be an inverse correlation between parasite load and atopy. These findings therefore suggest that the co-evolution of helminths with hosts, which has resulted in the ability of worms to modulate inflammatory responses to promote parasite survival, has also produced the benefit of protecting the host from pathological lesions arising from aggressive proinflammatory responses to infection or, indeed, aberrant inflammatory responses underlying autoimmune and allergic disorders. By focusing upon the properties of the filarial nematode-derived immunomodulatory molecule, ES-62, in this review we shall discuss the potential of exploiting the immunomodulatory products of parasitic worms to identify and develop novel therapeutics for inflammation