11,291 research outputs found

    Human Neural Stem Cells Genetically Modified to Overexpress Akt1 Provide Neuroprotection and Functional Improvement in Mouse Stroke Model

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    In a previous study, we have shown that human neural stem cells (hNSCs) transplanted in brain of mouse intracerebral hemorrhage (ICH) stroke model selectively migrate to the ICH lesion and induce behavioral recovery. However, low survival rate of grafted hNSCs in the brain precludes long-term therapeutic effect. We hypothesized that hNSCs overexpressing Akt1 transplanted into the lesion site could provide long-term improved survival of hNSCs, and behavioral recovery in mouse ICH model. F3 hNSC was genetically modified with a mouse Akt1 gene using a retroviral vector. F3 hNSCs expressing Akt1 were found to be highly resistant to H2O2-induced cytotoxicity in vitro. Following transplantation in ICH mouse brain, F3.Akt1 hNSCs induced behavioral improvement and significantly increased cell survival (50–100% increase) at 2 and 8 weeks post-transplantation as compared to parental F3 hNSCs. Brain transplantation of hNSCs overexpressing Akt1 in ICH animals provided functional recovery, and survival and differentiation of grafted hNSCs. These results indicate that the F3.Akt1 human NSCs should be a great value as a cellular source for the cellular therapy in animal models of human neurological disorders including ICH

    The Effect of Clonidine Pretreatment on Epidural Resiniferatoxin in a Neuropathic Pain Rat Model

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    Resiniferatoxin (RTX) is an ultrapotent synthetic TRPV1 (transient receptor potential vanilloid subtype 1) agonist with significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to thermal stimulus. Using a rat model of neuropathic pain, we evaluated the effect of pretreatment with clonidine-which has been shown to relieve intradermal capsaicin-induced hyperalgesia-on the initial hyperalgesic response and the thermal analgesic property of RTX. Thirty-six male rats were divided into 6 treatment groups (n=6 each):RTX 500ng, RTX 1μg, clonidine 20μg (Cl), Cl+RTX 500ng, Cl+RTX 1μg, or normal saline 20μL (control). We evaluated the short-term (180min) and long-term (20 days) analgesic effects of RTX after thermal stimulation and mechanical stimulation. RTX had significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to the thermal stimulus, but the RTX 500ng and RTX 1μg groups showed no initial short-term thermal hyperalgesic responses when pretreated with clonidine. The Cl+RTX 1μg ratsʼ behavior scores indicated that they were more calm and comfortable compared to the RTX 1μg rats. Even though we cannot precisely confirm that pretreatment with clonidine potentiates or adds to the analgesic effect of RTX, clonidine pretreatment with epidural RTX eliminated the initial RTX-associated hyperalgesic response and systemic toxicity in this neuropathic pain rat model

    Effect of magnetic order on the superfluid response of single-crystal ErNi2_{2}B2_{2}C: A penetration depth study

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    We report measurements of the in-plane magnetic penetration depth Δλ\Delta \lambda (T) in single crystals of ErNi2_{2}B2_{2}C down to \sim0.1 K using a tunnel-diode based, self-inductive technique at 21 MHz. We observe four features: (1) a slight dip in Δλ\Delta \lambda (T) at the Neˊ\acute{e}el temperature TNT_{N} = 6.0 K, (2) a peak at TWFMT_{WFM} = 2.3 K, where a weak ferromagnetic component sets in, (3) another maximum at 0.45 K, and (4) a final broad drop down to 0.1 K. Converting to superfluid density ρs\rho_{s}, we see that the antiferromagnetic order at 6 K only slightly depresses superconductivity. We seek to explain some of the above features in the context of antiferromagnetic superconductors, where competition between the antiferromagnetic molecular field and spin fluctuation scattering determines increased or decreased pairbreaking. Superfluid density data show only a slight decrease in pair density in the vicinity of the 2.3 K feature, thus supporting other evidences against bulk ferromagnetism in this temperature range.Comment: 15 pages, 5 figure

    Blocking binding of Bacillus thuringiensis Cry1Aa to Bombyx mori cadherin receptor results in only a minor reduction of toxicity

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    <p>Abstract</p> <p>Background</p> <p><it>Bacillus thuringiensis </it>Cry1Aa insecticidal protein is the most active known <it>B. thuringiensis </it>toxin against the forest insect pest <it>Lymantria dispar </it>(gypsy moth), unfortunately it is also highly toxic against the non-target insect <it>Bombyx mori </it>(silk worm).</p> <p>Results</p> <p>Surface exposed hydrophobic residues over domains II and III were targeted for site-directed mutagenesis. Substitution of a phenylalanine residue (F328) by alanine reduced binding to the <it>Bombyx mori </it>cadherin by 23-fold, reduced biological activity against <it>B. mori </it>by 4-fold, while retaining activity against <it>Lymantria dispar</it>.</p> <p>Conclusion</p> <p>The results identify a novel receptor-binding epitope and demonstrate that virtual elimination of binding to cadherin BR-175 does not completely remove toxicity in the case of <it>B. mori</it>.</p

    Data and videos for ultrafast synchrotron X-ray imaging studies of metal solidification under ultrasound.

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    The data presented in this article are related to the paper entitled 'Ultrafast synchrotron X-ray imaging studies of microstructure fragmentation in solidification under ultrasound' [Wang et al., Acta Mater. 144 (2018) 505-515]. This data article provides further supporting information and analytical methods, including the data from both experimental and numerical simulation, as well as the Matlab code for processing the X-ray images. Six videos constructed from the processed synchrotron X-ray images are also provided

    Contrast enhancement behavior of hydrogen silsesquioxane in a salty developer

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    The authors investigated a contrast enhancement behavior of hydrogen silsesquioxane (HSQ) in a salty development system (NaOH/NaCl). Time-resolved analysis of contrast curves and line-grating patterns were carried out to investigate the unique properties of a salty development process. In NaOH developer without salt, the development process was saturated beyond a certain development time. On the other hand, the addition of salt enabled a continuous development, which was not observed in the pure NaOH development. The continuous thinning process enhances the contrast of HSQ in the salty developer, which allows a fast collapsing behavior in HSQ line-grating patterns. During development process, salt seems to have the role of modifying HSQ by breaking network bonds preferentially, leading to a continuous development rate

    Far-infrared transmission studies of c-axis oriented superconducting MgB2 thin film

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    We reported far-infrared transmission measurements on a c-axis oriented superconducting MgB2_{2} thin film in the frequency range of 30 \sim 250 cm1^{-1}. We found that these measurements were sensitive to values of scattering rate 1/τ1/\tau and superconducting gap 2Δ2\Delta. By fitting the experimental transmission spectra at 40 K and below, we obtained 1/τ=1/\tau = (700 \sim 1000) cm1^{-1} and 2Δ(0)2\Delta (0)\cong 42 cm1^{-1}. These two quantities suggested that MgB2_{2} belong to the dirty limit.Comment: submitted at May
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