672 research outputs found

    Speed-dependent collision effects on radar back-scattering from the ionosphere

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    The question whether the differences between fluctuation spectra for linearly speed-dependent and speed-independent collision frequencies could account for disagreements between rocket and incoherent scatter estimate was addressed. The basic theory used for computing the fluctuation spectrum is outlined. The speed-dependence of the charge-neutral collision frequency is discussed, with special emphasis on its derivation from the mobility measurements. Various developments of the computer code used for the computation of the fluctuation spectrum are described. The range of values of input parameters typical to the collision-dominated ionosphere are briefly described. The computational results are presented, and the significance and limitation of these results and the future scope of the research are discussed

    3D printing of twisting and rotational bistable structures with tuning elements

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    Three-dimensional (3D) printing is ideal for the fabrication of various customized 3D components with fine details and material-design complexities. However, most components fabricated so far have been static structures with fixed shapes and functions. Here we introduce bistability to 3D printing to realize highly-controlled, reconfigurable structures. Particularly, we demonstrate 3D printing of twisting and rotational bistable structures. To this end, we have introduced special joints to construct twisting and rotational structures without post-assembly. Bistability produces a well-defined energy diagram, which is important for precise motion control and reconfigurable structures. Therefore, these bistable structures can be useful for simplified motion control in actuators or for mechanical switches. Moreover, we demonstrate tunable bistable components exploiting shape memory polymers. We can readjust the bistability-energy diagram (barrier height, slope, displacement, symmetry) after printing and achieve tunable bistability. This tunability can significantly increase the use of bistable structures in various 3D-printed components

    Mitochondrial Superoxide Contributes to Blood Flow and Axonal Transport Deficits in the Tg2576 Mouse Model of Alzheimer's Disease

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    Alzheimer's disease (AD) is a neurodegenerative disease characterized by the progressive decline in cognitive functions and the deposition of aggregated amyloid beta (Abeta) into senile plaques and the protein tau into tangles. In addition, a general state of oxidation has long been known to be a major hallmark of the disease. What is not known however, are the mechanisms by which oxidative stress contributes to the pathology of AD.In the current study, we used a mouse model of AD and genetically boosted its ability to quench free radicals of specific mitochondrial origin. We found that such manipulation conferred to the AD mice protection against vascular as well as neuronal deficits that typically affect them. We also found that the vascular deficits are improved via antioxidant modulation of the endothelial nitric oxide synthase, an enzyme primarily responsible for the production of nitric oxide, while neuronal deficits are improved via modulation of the phosphorylation status of the protein tau, which is a neuronal cytoskeletal stabilizer.These findings directly link free radicals of specific mitochondrial origin to AD-associated vascular and neuronal pathology

    Registration of ‘LCS Compass’ Wheat

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    ‘LCS Compass’ (Reg. No. CV-1149, PI 675458), a hard red winter (HRW) wheat (Triticum aestivum L.), was developed and tested as VA10HRW-13 and co-released by the Virginia Agricultural Experiment Station and Limagrain Cereal Seeds, LLC, in 2015. LCS Compass was derived from the cross ‘Vision 20’ /‘Stanof’ using a modified bulk breeding method. LCS Compass is a widely adapted, high-yielding, awned, semidwarf (Rht1) HRW wheat with early to medium maturity and resistance or moderate resistance to diseases prevalent in the mid-Atlantic and Great Plains regions of the United States. In the 2013 Uniform Bread Wheat Trial conducted over 18 locations in eastern states, LCS Compass produced an average grain yield of 4609 kg ha−1 that was similar to ‘Vision 30’ (4697 kg ha−1). In the northern Great Plains, the average grain yield of LCS Compass (4015 kg ha−1) over 44 locations in 2013 was similar to ‘Jerry’ (4013 kg ha−1). In the South Dakota crop zone 3 variety test, LCS Compass had a 3-yr (2015–2017) yield average of 5575 kg ha−1 and was one of highest-yielding cultivars among the 19 cultivars tested over the 3-yr period. LCS Compass has good end-use quality in both the eastern and Great Plains regions of the United States

    Original article title: "Comparison of therapeutic efficacy of topical corticosteroid and oral zinc sulfate-topical corticosteroid combination in the treatment of vitiligo patients: a clinical trial"

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    <p>Abstract</p> <p>Background</p> <p>Vitiligo is the most prevalent pigmentary disorder which occurs worldwide, with an incidence rate between 0.1-4 percent. It is anticipated that the discovery of biological pathways of vitiligo pathogenesis will provide novel therapeutic and prophylactic targets for future approaches to the treatment and prevention of vitiligo. The purposes of this study were evaluating the efficacy of supplemental zinc on the treatment of vitiligo.</p> <p>Methods</p> <p>This randomized clinical trial was conducted for a period of one year. Thirty five patients among 86 participants were eligible to entrance to the study. The patients in two equal randomized groups took topical corticosteroid and combination of oral zinc sulfate-topical corticosteroid.</p> <p>Results</p> <p>The mean of responses in the corticosteroid group and the zinc sulfate-corticosteroid combination group were 21.43% and 24.7%, respectively.</p> <p>Conclusion</p> <p>Although, the response to corticosteroid plus zinc sulfate was more than corticosteroid, there was no statistically significant difference between them. It appeared that more robust long-term randomized controlled trials on more patients, maybe with higher doses of zinc sulfate, are needed to fully establish the efficacy of oral zinc in management of vitiligo.</p> <p>Trial Registration</p> <p>chiCTRTRC10000930</p

    Direct targeting of hippocampal neurons for apoptosis by glucocorticoids is reversible by mineralocorticoid receptor activation

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    Prova tipográfica (In Press)An important question arising from previous observations in vivo is whether glucocorticoids can directly influence neuronal survival in the hippocampus. To this end, a primary postnatal hippocampal culture system containing mature neurons and expressing both glucocorticoid (GR) and mineralocorticoid (MR) receptors was developed. Results show that the GR agonist dexamethasone (DEX) targets neurons (microtubule-associated protein 2-positive cells) for death through apoptosis. GR-mediated cell death was counteracted by the MR agonist aldosterone (ALDO). Antagonism of MR with spironolactone ([7a-(acetylthio)-3-oxo-17a-pregn- 4-ene,21 carbolactone] (SPIRO)) causes a dose-dependent increase in neuronal apoptosis in the absence of DEX, indicating that nanomolar levels of corticosterone present in the culture medium, which are sufficient to activate MR, can mask the apoptotic response to DEX. Indeed, both SPIRO and another MR antagonist, oxprenoate potassium ((7a,17a)-17-Hydroxy-3-oxo-7- propylpregn-4-ene-21-carboxylic acid, potassium salt (RU28318)), accentuated DEX-induced apoptosis. These results demonstrate that GRs can act directly to induce hippocampal neuronal death and that demonstration of their full apoptotic potency depends on abolition of survival-promoting actions mediated by MR

    Crosstalk between JNK and SUMO Signaling Pathways: deSUMOylation Is Protective against H2O2-Induced Cell Injury

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    Background: Oxidative stress is a key feature in the pathogenesis of several neurological disorders. Following oxidative stress stimuli a wide range of pathways are activated and contribute to cellular death. The mechanism that couples c-Jun N-terminal kinase (JNK) signaling, a key pathway in stress conditions, to the small ubiquitin-related modifier (SUMO), an emerging protein in the field, is largely unknown. Methodology/Principal Findings: With this study we investigated if SUMOylation participates in the regulation of JNK activation as well as cellular death in a model of H 2O 2 induced-oxidative stress. Our data show that H 2O 2 modulates JNK activation and induces cellular death in neuroblastoma SH-SY5Y cells. Inhibition of JNK’s action with the D-JNKI1 peptide rescued cells from death. Following H2O2, SUMO-1 over-expression increased phosphorylation of JNK and exacerbated cell death, although only in conditions of mild oxidative stress. Furthermore inhibition of SUMOylation, following transfection with SENP1, interfered with JNK activation and rescued cells from H 2O 2 induced death. Importantly, in our model, direct interaction between these proteins can occur. Conclusions/Significance: Taken together our results show that SUMOylation may significantly contribute to modulation o

    Effects of NK-4 in a Transgenic Mouse Model of Alzheimer's Disease

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    Beta-amyloid (Aβ) peptides are considered to play a major role in the pathogenesis of Alzheimer's disease (AD) and molecules that can prevent pathways of Aβ toxicity may be potential therapeutic agents for treatment of AD. We have previously reported that NK-4, a cyanine photosensitizing dye, displays neurotrophic and antioxidant activities. In this study, we report the effects of NK-4 on the toxicity of Aβ and on cognitive function and Aβ concentration in a transgenic mouse model of AD (Tg2576). In vitro, NK-4 effectively protected neuronal cells from toxicity induced by Aβ. In addition, it displayed profound inhibitory activities on Aβ fibril formation. In vivo, Tg2576 mice received an intraperitoneal injection at 100 or 500 µg/kg of NK-4 once a day, five times a week for 9 months. Administration of NK-4 to the mice attenuated impairment of recognition memory, associative memory, and learning ability, as assessed by a novel object recognition test, a passive avoidance test, and a water maze test, respectively. NK-4 decreased the brain Aβ concentration while increasing the plasma amyloid level in a dose-dependent manner. NK-4 also improved memory impairments of ICR mice induced by direct intracerebroventricular administration of Aβ. These lines of evidence suggest that NK-4 may affect multiple pathways of amyloid pathogenesis and could be useful for treatment of AD
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