Dynamics of ferromagnetic nanomagnets with vortex or single-domain configuration

We study the dynamics of flat circular permalloy nanomagnets for 1.) magnetic vortex and 2.) single-domain configurations, using micromagnetic simulation. Dynamical studies for isolated vortex structures show that both the vorticity and the central polarity of the out-of-plane component can be switched fast (50-100 ps) and independently. Micromagnetic simulations of the switching process in thin cylindrical Permalloy (Py) nanoparticles with an initial stable single-domain state show nearly homogeneous single-domain behaviour followed by excitation of spin waves.Comment: 2 pages with 3 eps-figures, --> ICM2003 Rome 28.7.-1.8.03, --> JMM

What Did I Miss? A Demonstration of the Differences Between ChatGPT-4 and 3.5 that Impact Legal Research and Writing

Many news sources are raving about how much more advanced ChatGPT-4 is than 3.5. You may have heard that ChatGPT-4 outscored 90% of test takers on the Uniform Bar Exam, while ChatGPT 3.5 only outscored 10% of test takers. But what does this mean for teaching legal research and writing? In this presentation, we will compare specific examples of ChatGPT 3.5 (the free version many of us tried in the spring) and ChatGPT-4 (the paid version released in March)

Characterization of α‑synuclein multimer stoichiometry in complex biological samples by electrophoresis

The aberrant aggregation of α-synuclein in the brain is a hallmark of Parkinson’s disease (PD). In vivo soluble α-synuclein occurs as a monomer and several multimers, the latter of which may be important for the biological function of α-synuclein. Currently, there is a lack of reproducible methods to compare α-synuclein multimer abundance between complex biological samples. Here we developed a method, termed “multimer-PAGE,” that combines in-gel chemical cross-linking with several common electrophoretic techniques to measure the stoichiometry of soluble α-synuclein multimers in brain tissue lysates. Results show that soluble α-synuclein from the rat brain exists as several high molecular weight species of approximately 56 kDa (αS56), 80 kDa (αS80), and 100 kDa (αS100) that comigrate with endogenous lipids, detergents, and/or micelles during blue native gel electrophoresis (BN-PAGE). Co-extraction of endogenous lipids with α-synuclein was essential for the detection of soluble α-synuclein multimers. Homogenization of brain tissue in small buffer volumes (\u3e50 mg tissue per 1 mL buffer) increased relative lipid extraction and subsequently resulted in abundant soluble multimer detection via multimer-PAGE. α-Synuclein multimers captured by directly cross-linking soluble lysates resembled those observed following multimer-PAGE. The ratio of multimer (αS80) to monomer (αS17) increased linearly with protein input into multimer-PAGE, suggesting to some extent, multimers were also formed during electrophoresis. Overall, soluble α-synuclein maintains lipid interactions following tissue disruption and readily forms multimers when this lipid–protein complex is preserved. Once the multimer-PAGE technique was validated, relative stoichiometric comparisons could be conducted simultaneously between 14 biological samples. Multimer-PAGE provides a simple inexpensive biochemical technique to study the molecular factors influencing α-synuclein multimerization

Processing and characterisation of High-Velocity Suspension Flame Sprayed (HVSFS) bioactive glass coatings

The High-Velocity Suspension Flame Spraying (HVSFS) technique was employed in order to deposit bioactive glass coatings onto titanium substrates. Two different glass compositions were examined: the classical 45S5 Bioglass and a newly-developed SiO2–CaO–K2O–P2O5 glass, labelled as “Bio-K”. Suitable raw materials were melted in a furnace and fritted by casting into water. The frit was dry-milled in a porcelain jar and subsequently attrition-milled in isopropanol. The resulting micron- sized powders were dispersed in a water+isopropanol mixture, in order to prepare suitable suspensions for the HVSFS process. The deposition parameters were varied; however, all coatings were obtained by performing three consecutive torch cycles in front of the substrate. The thickness and porosity of the coatings were significantly affected by the chosen set of deposition parameters; however, in all cases, the layer produced during the third torch cycle was thicker and denser than the one produced during the first cycle. As the system temperature increases during the spraying process, the particles sprayed during the last torch cycle remain at T > Tg while they spread, so that interlamellar viscous flow sintering takes place, favouring the formation of such denser microstructure. Both coatings are entirely glassy; however, micro-Raman spectroscopy reveals that, whereas the 45S5 coating is structurally identical to the corresponding bulk glass, the “Bio-K” coating is somewhat different from the bulk one

Effect of the suspension composition on the microstructural properties of high velocity suspension flame sprayed (HVSFS) Al2O3 coatings

Seven different Al2O3-based suspensions were prepared by dispersing two nano-sized Al2O3 powders (having analogous size distribution and chemical composition but different surface chemistry), one micron-sized powder and their mixtures in a water+isopropanol solution. High velocity suspension flame sprayed (HVSFS) coatings were deposited using these suspensions as feedstock and adopting two different sets of spray parameters. The characteristics of the suspension, particularly its agglomeration behaviour, have a significant influence on the coating deposition mechanism and, hence, on its properties (microstructure, hardness, elastic modulus). Dense and very smooth (Ra ~ 1.3 μm) coatings, consisting of well- flattened lamellae having a homogeneous size distribution, are obtained when micron-sized (~1 -2 μm) powders with low tendency to agglomeration are employed. Spray parameters favouring the break-up of the few agglomerates present in the suspension enhance the deposition efficiency (up to >50%), as no particle or agglomerate larger than ~2.5 μm can be fully melted. Nano-sized powders, by contrast, generally form stronger agglomerates, which cannot be significantly disrupted by adjusting the spray parameters. If the chosen nanopowder forms small agglomerates (up to few microns), the deposition efficiency is satisfactory and the coating porosity is limited, although the lamellae generally have a wider size distribution, so that roughness is somewhat higher. If the nanopowder forms large agglomerates (on account of its surfacechemistry), poor deposition efficiencies and porous layers are obtained. Although suspensions containing the pure micron-sized powder produce the densest coatings, the highest deposition efficiency (~70%) is obtained by suitable mixtures of micron-and nano-sized powders, on account of synergistic effect

Coexisting depressive symptoms do not limit the benefits of chronic neuromodulation: A study of over 200 patients

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142918/1/nau23356_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142918/2/nau23356.pd