807 research outputs found

    Comparison of Estrone and 17β-Estradiol Levels in Commercial Goat and Cow Milk

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    Increased levels of estrogen metabolites are believed to be associated with cancers of the reproductive system. One potential dietary source of these metabolites that is commonly consumed worldwide is milk. In North America, dairy cows are the most common source of milk; however, goats are the primary source of milk worldwide. In this study, the absolute concentrations of unconjugated and total (unconjugated plus conjugated) estrone (E(1)) and 17β-estradiol (E(2)) were compared in a variety of commercial cow milks (regular and organic) and goat milk. A lower combined concentration of E(1) and E(2) was found in goat milk than in any of the cow milk products tested. The differences in E(1) and E(2) levels between regular and organic cow milks were not as significant as the differences between goat milk and any of the cow milk products. Goat milk represents a better dietary choice for individuals concerned with limiting their estrogen intake

    A Review of Dementia with Lewy Bodies' Impact, Diagnostic Criteria and Treatment

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    Dementia with Lewy bodies is one of the most common causes of dementia. It is not as common as Alzheimer's disease; the general public's awareness of the disease is poor in comparison. Its effects on caregivers and patients alike are not well known to the general population. There are currently no FDA-approved medications specifically for the treatment of DLB. Many of the medications that are approved for Alzheimer's disease are widely used in the treatment of DLB with varying degrees of success. Treatment of DLB is life long and requires a dedicated team of physicians and caregivers to minimize the degree of morbidity and mortality experienced by the patients suffering from the disease as it progresses

    Occupational health and safety: a comment on Mullen

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    The paper by Elizabeth A. Mullen (1990) contains a number of assumptions and assertions that cannot be allowed to pass unchallenged. In addition, the survey itself seems to be based on an inappropriate sample with the particular interpretation of results creating a potentially false impression. The debate concerning the Code of Practice for Health and Safety Representatives and Health and Safety Committees has often been plagued with confusion and misunderstanding and, regrettably, Mullen's paper continues these problems

    Mount St. Helens aerosol evolution

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    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mount St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months

    Introduction and recovery of point defects in electron-irradiated ZnO

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    We have used positron annihilation spectroscopy to study the introduction and recovery of point defects in electron-irradiated n-type ZnO. The irradiation (Eel=2MeV, fluence 6×10 exp 17 cm exp −2) was performed at room temperature, and isochronal annealings were performed from 300 to 600 K. In addition, monochromatic illumination of the samples during low-temperature positron measurements was used in identification of the defects. We distinguish two kinds of vacancy defects: the Zn and O vacancies, which are either isolated or belong to defect complexes. In addition, we observe negative-ion-type defects, which are attributed to O interstitials or O antisites. The Zn vacancies and negative ions act as compensating centers and are introduced at a concentration [VZn]≃cion≃2×10 exp 16 cm exp −3. The O vacancies are introduced at a 10-times-larger concentration [VO]≃3×10 exp 17 cm exp −3 and are suggested to be isolated. The O vacancies are observed as neutral at low temperatures, and an ionization energy of 100 meV could be fitted with the help of temperature-dependent Hall data, thus indicating their deep donor character. The irradiation-induced defects fully recover after the annealing at 600 K, in good agreement with electrical measurements. The Zn vacancies recover in two separate stages, indicating that the Zn vacancies are parts of two different defect complexes. The O vacancies anneal simultaneously with the Zn vacancies at the later stage, with an activation energy of EmV,O = 1.8 ± 0.1 eV. The negative ions anneal out between the two annealing stages of the vacancies.Peer reviewe

    Introduction and recovery of Ga and N sublattice defects in electron-irradiated GaN

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    We have used positron annihilation spectroscopy to study the introduction and recovery of point defects introduced by 0.45 and 2 MeV electron irradiation at room temperature in n-type GaN. Isochronal annealings were performed up to 1220 K. We observe vacancy defects with specific lifetime of τV=190±15ps that we tentatively identify as N vacancies or related complexes in the neutral charge state in the samples irradiated with 0.45MeV electrons. The N vacancies are produced at a rate Σ0.45N≃0.25 cm exp −1. The irradiation with 2 MeV electrons produces negatively charged Ga vacancies and negative nonopen volume defects (negative ions) originating from the Ga sublattice, at a rate Σ2.0Ga≃5cm exp −1. The irradiation-induced N vacancies anneal out of the samples at around 600 K, possibly due to the motion of the irradiation-induced N interstitials. Half of the irradiation-induced Ga vacancies anneal out of the samples also around 600 K, and this is interpreted as the isolated Ga vacancies becoming mobile with a migration barrier of EV,GaM=1.8±0.1eV. Interestingly, we observe a change of charge state of the irradiation-induced negative ions from 2− to 1− likely due to a reconstruction of the defects in two stages at annealing temperatures of about 600 and 700 K. The negative ions anneal out of the samples together with the other half of the Ga vacancies (stabilized by, e.g., N vacancies and/or hydrogen) in thermal annealings at 800–1100K.Peer reviewe

    Formation of targeted monovalent quantum dots by steric exclusion

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    Precise control over interfacial chemistry between nanoparticles and other materials remains a significant challenge limiting the broad application of nanotechnology in biology. To address this challenge, we use “Steric Exclusion” to completely convert commercial quantum dots (QDs) into monovalent imaging probes by wrapping the QD with a functionalized oligonucleotide. We demonstrate the utility of these QDs as modular and non-perturbing imaging probes by tracking individual Notch receptors on live cells

    Air-Coupled Ultrasonic Transducers for the Detection of Defects in Plates

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    In order to minimise the problems due to the acoustic impedance mismatch between solids and air, the non destructive testing of materials using ultrasonic transducers generally requires either contact transducers or immersion transducers to be used [1]. Air-coupled transducers however would be very advantageous for testing structures which must be not contaminated with couplant and also for all in-situ industrial applications. Although the propagation of ultrasonic waves from laser generation [2] involves air-coupling, the difficulties due to the experimental set-up of this technique and the financial investment it implies are two major disadvantages

    Genome-wide association of familial late-onset alzheimer's disease replicates BIN1 and CLU and nominates CUGBP2 in interaction with APOE

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    Late-onset Alzheimer's disease (LOAD) is the most common form of dementia in the elderly. The National Institute of Aging-Late Onset Alzheimer's Disease Family Study and the National Cell Repository for Alzheimer's Disease conducted a joint genome-wide association study (GWAS) of multiplex LOAD families (3,839 affected and unaffected individuals from 992 families plus additional unrelated neurologically evaluated normal subjects) using the 610 IlluminaQuad panel. This cohort represents the largest family-based GWAS of LOAD to date, with analyses limited here to the European-American subjects. SNPs near APOE gave highly significant results (e.g., rs2075650, p = 3.2×10-81), but no other genome-wide significant evidence for association was obtained in the full sample. Analyses that stratified on APOE genotypes identified SNPs on chromosome 10p14 in CUGBP2 with genome-wide significant evidence for association within APOE ε4 homozygotes (e.g., rs201119, p = 1.5×10-8). Association in this gene was replicated in an independent sample consisting of three cohorts. There was evidence of association for recently-reported LOAD risk loci, including BIN1 (rs7561528, p = 0.009 with, and p = 0.03 without, APOE adjustment) and CLU (rs11136000, p = 0.023 with, and p = 0.008 without, APOE adjustment), with weaker support for CR1. However, our results provide strong evidence that association with PICALM (rs3851179, p = 0.69 with, and p = 0.039 without, APOE adjustment) and EXOC3L2 is affected by correlation with APOE, and thus may represent spurious association. Our results indicate that genetic structure coupled with ascertainment bias resulting from the strong APOE association affect genome-wide results and interpretation of some recently reported associations. We show that a locus such as APOE, with large effects and strong association with disease, can lead to samples that require appropriate adjustment for this locus to avoid both false positive and false negative evidence of association. We suggest that similar adjustments may also be needed for many other large multi-site studies. © 2011 Wijsman et al
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