Widespread Increases in Malondialdehyde Immunoreactivity in Dopamine-Rich and Dopamine-Poor Regions of Rat Brain Following Multiple, High Doses of Methamphetamine

Treatment with multiple high doses of methamphetamine (METH) can induce oxidative damage, including dopamine (DA)-mediated reactive oxygen species (ROS) formation, which may contribute to the neurotoxic damage of monoamine neurons and long-term depletion of DA in the caudate putamen (CPu) and substantia nigra pars compacta (SNpc). Malondialdehyde (MDA), a product of lipid peroxidation by ROS, is commonly used as a marker of oxidative damage and treatment with multiple high doses of METH increases MDA reactivity in the CPu of humans and experimental animals. Recent data indicate that MDA itself may contribute to the destruction of DA neurons, as MDA causes the accumulation of toxic intermediates of DA metabolism via its chemical modification of the enzymes necessary for the breakdown of DA. However, it has been shown that in human METH abusers there is also increased MDA reactivity in the frontal cortex, which receives relatively fewer DA afferents than the CPu. These data suggest that METH may induce neuronal damage regardless of the regional density of DA or origin of DA input. The goal of the current study was to examine the modification of proteins by MDA in the DA-rich nigrostriatal and mesoaccumbal systems, as well as the less DA-dense cortex and hippocampus following a neurotoxic regimen of METH treatment. Animals were treated with METH (10 mg/kg) every 2 h for 6 h, sacrificed 1 week later, and examined using immunocytochemistry for changes in MDA-adducted proteins. Multiple, high doses of METH significantly increased MDA immunoreactivity (MDA-ir) in the CPu, SNpc, cortex, and hippocampus. Multiple METH administration also increased MDA-ir in the ventral tegmental area and nucleus accumbens. Our data indicate that multiple METH treatment can induce persistent and widespread neuronal damage that may not necessarily be limited to the nigrostriatal DA system

An analysis of automatic teller machine usage by older adults : a structured interview approach.

It is often assumed that automatic teller machines (ATMs) are inherently easy to use and require no training. However, there is evidence to suggest that ATM users do experience difficulty when learning to use the system. The purpose of the present study was to conduct an in-depth analysis of ATM usage by older adults. Our approach consisted of telephone interviews followed by structured individual interviews. The goals were to understand the problems encountered by ATM users, to determine how ATMs might be better designed and to assess the training needs of older individuals. The phone interview data provide information about the relationships between age, sex and ATM usage within the adult sample, as well as information about why some people choose not to use ATMs. The structured interview data provide a more in-depth view of the concerns of both users and non-users, and information about training needs. The training and design implications of the results are discussed

The effects of immersive simulation on targeted collaboration skills among undergraduates in special education

The use of immersive simulation as a pedagogical tool has great potential for making a significant impact on student learning in higher education. In this study, the effect of immersive simulation was evaluated for a cohort of undergraduate special education majors. The investigation aimed to determine whether facilitating an immersive co-planning simulation would have an impact on targeted collaboration skills and whether vicarious observational learning would occur for students who observed the simulation. Pre-service teachers in special education were evaluated by their peers on their ability to demonstrate knowledge of (1) co-teaching and co-planning, (2) professional communication, and (3) supports for students with disabilities. The results indicate that they did a better job of facilitating a co-planning session after having first practiced doing so via immersive simulation during a previous class session. It was also discovered that vicarious observational learning during immersive simulation positively affected performance

A survey of automatic teller machine usage across the adult lifespan.

The purpose of this study was to analyze automatic teller machine (ATM) usage across the adult life span. We conducted an extensive survey of 9000 people in the Memphis and Atlanta metropolitan areas. Approximately 17% of those people responded. The survey assessed detailed demographic information, experience with technology in general, experience specifically related to ATMs, problems and dislikes with ATMs, and reasons that people do not use ATMs. The survey provided a valuable set of data. First, we have detailed information about the demographics and individual characteristics of ATM users and nonusers; importantly, these data are stratified across the adult life span. In addition, we know the likes and dislikes of ATM users and the types of problems they typically have using ATMs. Moreover, we have a detailed analysis of why adults of all ages may choose not to use ATMs. Training and design implications of these data are discussed

Livestock abundance predicts vampire bat demography, immune profiles, and bacterial infection risk

Human activities create novel food resources that can alter wildlife–pathogen interactions. If resources amplify or dampen, pathogen transmission probably depends on both host ecology and pathogen biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a 4-year study of 369 common vampire bats across 10 sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria. We predicted that abundant livestock could reduce starvation and foraging effort, allowing for greater investments in immunity. Bats from high-livestock sites had higher microbicidal activity and proportions of neutrophils but lower immunoglobulin G and proportions of lymphocytes, suggesting more investment in innate relative to adaptive immunity and either greater chronic stress or pathogen exposure. This relationship was most pronounced in reproductive bats, which were also more common in high-livestock sites, suggesting feedbacks between demographic correlates of provisioning and immunity. Infection with both Bartonella and haemoplasmas were correlated with similar immune profiles, and both pathogens tended to be less prevalent in high-livestock sites, although effects were weaker for haemoplasmas. These differing responses to provisioning might therefore reflect distinct transmission processes. Predicting how provisioning alters host–pathogen interactions requires considering how both within-host processes and transmission modes respond to resource shifts

The effect of polymer stiffness on magnetization reversal of magnetorheological elastomers

Ultrasoft magnetorheological elastomers (MREs) offer convenient real-time magnetic field control of mechanical properties that provides a means to mimic mechanical cues and regulators of cells in vitro. Here, we systematically investigate the effect of polymer stiffness on magnetization reversal of MREs using a combination of magnetometry measurements and computational modeling. Poly-dimethylsiloxane- based MREs with Young’s moduli that range over two orders of magnitude were synthesized using commercial polymers SylgardTM 527, Sylgard 184, and carbonyl iron powder. The magnetic hysteresis loops of the softer MREs exhibit a characteristic pinched loop shape with almost zero remanence and loop widening at intermediate fields that monotonically decreases with increasing polymer stiffness. A simple two-dipole model that incorporates magneto-mechanical coupling not only confirms that micrometer-scale particle motion along the applied magnetic field direction plays a defining role in the magnetic hysteresis of ultrasoft MREs but also reproduces the observed loop shapes and widening trends for MREs with varying polymer stiffnesses

New Reversal Mode in Exchange Coupled Antiferromagnetic/Ferromagnetic Disks: Distorted Viscous Vortex

Magnetic vortices have generated intense interest in recent years due to their unique reversal mechanisms, fascinating topological properties, and exciting potential applications. Additionally, the exchange coupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novel phenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vortices in exchange coupled Ir20Mn80/Fe20Ni80 microdots: distorted viscous vortex reversal. Contrary to the previously known or proposed reversal modes, the vortex is distorted close to the interface and viscously dragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpected asymmetries in the annihilation and nucleation fields. These results provide a deeper understanding of the physics of exchange coupled vortices and may also have important implications for applications involving exchange coupled nanostructures.Comment: 27 pages, 4 figures and a supplemental information sectio

A new reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks: distorted viscous vortex

Magnetic vortices have generated intense interest in recent years due to their unique reversal mecha-nisms, fascinating topological properties, and exciting potential applications. In addition, the exchangecoupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novelphenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vorticesin exchange coupled Ir20Mn80/Fe20Ni80microdots: distorted viscous vortex reversal. In contrast to thepreviously known or proposed reversal modes, the vortex is distorted close to the interface and viscouslydragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpected asymme-tries in the annihilation and nucleationfields. These results provide a deeper understanding of the physicsof exchange coupled vortices and may also have important implications for applications involvingexchange coupled nanostructure

Neural Tube Defects and Folate Pathway Genes: Family-Based Association Tests of Gene–Gene and Gene–Environment Interactions

BACKGROUND: Folate metabolism pathway genes have been examined for association with neural tube defects (NTDs) because folic acid supplementation reduces the risk of this debilitating birth defect. Most studies addressed these genes individually, often with different populations providing conflicting results. OBJECTIVES: Our study evaluates several folate pathway genes for association with human NTDs, incorporating an environmental cofactor: maternal folate supplementation. METHODS: In 304 Caucasian American NTD families with myelomeningocele or anencephaly, we examined 28 polymorphisms in 11 genes: folate receptor 1, folate receptor 2, solute carrier family 19 member 1, transcobalamin II, methylenetetrahydrofolate dehydrogenase 1, serine hydroxymethyl-transferase 1, 5,10-methylenetetrahydrofolate reductase (MTHFR), 5-methyltetrahydrofolate-homo-cysteine methyltransferase, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase, betaine-homocysteine methyltransferase (BHMT), and cystathionine-beta-synthase. RESULTS: Only single nucleotide polymorphisms (SNPs) in BHMT were significantly associated in the overall data set; this significance was strongest when mothers took folate-containing nutritional supplements before conception. The BHMT SNP rs3733890 was more significant when the data were stratified by preferential transmission of the MTHFR rs1801133 thermolabile T allele from parent to offspring. Other SNPs in folate pathway genes were marginally significant in some analyses when stratified by maternal supplementation, MTHFR, or BHMT allele transmission. CONCLUSIONS: BHMT rs3733890 is significantly associated in our data set, whereas MTHFR rs1801133 is not a major risk factor. Further investigation of folate and methionine cycle genes will require extensive SNP genotyping and/or resequencing to identify novel variants, inclusion of environmental factors, and investigation of gene–gene interactions in large data sets