Current-induced domain wall motion in a nanowire with perpendicular magnetic anisotropy

We study theoretically the current-induced magnetic domain wall motion in a metallic nanowire with perpendicular magnetic anisotropy. The anisotropy can reduce the critical current density of the domain wall motion. We explain the reduction mechanism and identify the maximal reduction conditions. This result facilitates both fundamental studies and device applications of the current- induced domain wall motion

On the notation of the "Yotsu-Gana" that appear in Japanese learning books of the Chosen Period

This paper basing on Japanese learning books of the Chosen Period has the purpose of giving a report on the actual condition of the confusion of the 'Yotsu-Gana' that appear in these materials and the application of it on the history of the Japanese language. Research on the confusion of the 'Yotsu-Gana'is almost solely based on Kana materials, Christian materials or Chinese materials, leaving out a comprehensive research from Korean materials. The approach of one more aspect, namely Korean materials, cannot be left out from the research on the actual condition of the confusion of the 'Yotsu-Gana'. A new approach from this angle will give an opportunity to reconsider already existing various accounts, and at the same time it will give abundant sources to approach the problem of the confusion

An Innovative Inflatable Morphing Body Structure for Crashworthiness of Military and Commercial Vehicles.

The greatest demand facing the automotive industry has been to provide safer vehicles with high fuel efficiency at minimum cost. Current automotive vehicle structures have one fundamental handicap: a short crumple zone for crash energy absorption. This leaves limited room for further safety improvements, especially for high-speed crashes. Breakthrough technologies are needed. One potential breakthrough is to use active devices instead of conventional passive devices. An innovative inflatable bumper concept, called the “I-bumper,” is developed in this research for improved crashworthiness and safety of military and commercial vehicles. The developed I-bumper has several active structural components, including a morphing mechanism, a movable bumper, two explosive airbags, and a morphing lattice structure with a locking mechanism that provides desired rigidity and energy absorption capability during a vehicular crash. Another additional innovative means for improving crashworthiness is the use of tubes filled with a granular material to absorb energy during the process of a crash. An analytical design model is also developed in this research for the optimal design of the I-bumper system, with a focus on up-front design. Major design variables include those of the explosive airbag, the morphing lattice structure, and the granular material used in the front posts. The morphing lattice structure is designed to maximize energy absorption during the crash impact. The granular material in the front posts is used for further crash energy management in the passive stage. The new design methodology has been implemented in MATLAB and validation has been conducted at a full vehicle level in order to demonstrate the effectiveness of the I-bumper for improved suitability in a high-speed crash. In future research, this I-bumper can be extended to address other types of crashes (for example, side impacts, rear impacts, roll over, and collision with pedestrian) and to innovative blast-worthiness applications for military vehicles. The main achievement of this work has been an introduction of the I-bumper and the development of an analytical model of the I-bumper for absorbed energy during a crash.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58507/1/sonlee_1.pd

Subtle cytotoxicity and genotoxicity differences in superparamagnetic iron oxide nanoparticles coated with various functional groups

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely utilized for the diagnosis and therapy of specific diseases, as magnetic resonance imaging (MRI) contrast agents and drug-delivery carriers, due to their easy transportation to targeted areas by an external magnetic field. For such biomedical applications, SPIONs must have multifunctional characteristics, including optimized size and modified surface. However, the biofunctionality and biocompatibility of SPIONs with various surface functional groups of different sizes have yet to be elucidated clearly. Therefore, it is important to carefully monitor the cytotoxicity and genotoxicity of SPIONs that are surfaced-modified with various functional groups of different sizes. In this study, we evaluated SPIONs with diameters of approximately 10 nm and 100~150 nm, containing different surface functional groups. SPIONs were covered with −O− groups, so-called bare SPIONs. Following this, they were modified with three different functional groups – hydroxyl (−OH), carboxylic (−COOH), and amine (−NH2) groups – by coating their surfaces with tetraethyl orthosilicate (TEOS), (3-aminopropyl)trimethoxysilane (APTMS), TEOS-APTMS, or citrate, which imparted different surface charges and sizes to the particles. The effects of SPIONs coated with these functional groups on mitochondrial activity, intracellular accumulation of reactive oxygen species, membrane integrity, and DNA stability in L-929 fibroblasts were determined by water-soluble tetrazolium, 2′,7′-dichlorodihydrofluorescein, lactate dehydrogenase, and comet assays, respectively. Our toxicological observations suggest that the functional groups and sizes of SPIONs are critical determinants of cellular responses, degrees of cytotoxicity and genotoxicity, and potential mechanisms of toxicity. Nanoparticles with various surface modifications and of different sizes induced slight, but possibly meaningful, changes in cell cytotoxicity and genotoxicity, which would be significantly valuable in further studies of bioconjugation and cell interaction for drug delivery, cell culture, and cancer-targeting applications

Constraints on Scalar-Field Dark Energy from the Cosmic Lens All-Sky Survey Gravitational Lens Statistics

We use the statistics of strong gravitational lensing based on the Cosmic Lens All-Sky Survey (CLASS) data to constrain cosmological parameters in a spatially-flat, inverse power-law potential energy density, scalar-field dark energy cosmological model. The lensing-based constraints are consistent with, but weaker than, those derived from Type Ia supernova redshift-magnitude data, and mildly favor the Einstein cosmological constant limit of this dark energy model.Comment: 10 pages, 1 figure; ApJL, in press; minor additions, new referenc

The effect of high-speed power training on physical frailty in older adults: Effect of a visual-guided exercise program in South Korean rural areas

Objective. Exercise has been shown to be an effective intervention; the difficulty still lies in providing exercise programs to the older adults in rural areas. Therefore, this study aimed to examine the effects of a 12-week exercise program provided with visual guidelines (prerecorded video) on frailty among older adults in rural areas. Methods. Fifty participants (71.7 ± 4.9 years) from 5 different rural areas were recruited and divided into two groups: the exercise group (EX, n = 24 (male: 8, female: 18)) and the control group (CON, n = 26 (male: 7, female: 17)). With the commencement of the exercise intervention, a prerecorded high-speed power training program for frail older adults was distributed to the EX group. A new prerecorded exercise program was delivered to the EX group every 4 weeks. Frailty status was diagnosed with Fried’s criteria before and after the intervention. Muscle strength was measured in the upper and lower limb strength (hand-grip strength and leg extension and flexion), and physical function was measured using a short physical performance battery and gait speed. Fasting blood was collected before and after the intervention and analyzed for blood lipid profile. Results. After 12 weeks of the intervention period, a significant difference in frailty status () and score () favoring the EX group was observed. Physical functions (gait speed () and time for sit to stand ()) were significantly improved in the EX group with a significant increase in knee extensor strength (). A significant difference in serum high-density lipoprotein levels favoring the EX group () was also observed. Conclusions. This study confirmed the positive effect of a visual-guided exercise program on older adults’ residents in rural areas and provided alternative methods to effectively provide exercise program for the older adults with limited resources

Evolution of rubisco complex small subunit transit peptides from algae to plants

Chloroplasts evolved from a free-living cyanobacterium acquired by the ancestor of all photosynthetic eukaryotes, including algae and plants, through a single endosymbiotic event. During endosymbiotic conversion, the majority of genes in the endosymbiont were transferred to the host nucleus and many of the proteins encoded by these genes must therefore be transported into the chloroplast after translation in the cytosol. Chloroplast-targeted proteins contain a targeting signal, named the transit peptide (TP), at the N-terminus. However, the evolution of TPs is not well understood. In this study, TPs from RbcS (rubisco small subunit) were compared between lower and higher eukaryotes. Chlamydomonas reinhardtii RbcS (CrRbcS) TP was non-functional in Arabidopsis. However, inclusion of a critical sequence motif, FP-RK, from Arabidopsis thaliana RbcS (AtRbcS) TP allowed CrRbcS TP to deliver proteins into plant chloroplasts. The position of the FP-RK motif in CrRbcS TP was critical for function. The QMMVW sequence motif in CrRbcS TP was crucial for its transport activity in plants. CrRbcS TPs containing additional plant motifs remained functional in C. reinhardtii. These results suggest that TPs evolved by acquiring additional sequence motifs to support protein targeting to chloroplasts during evolution of land plants from algae.113Ysciescopu