29,504 research outputs found

    Corticotropin-releasing factor receptors couple to multiple g-proteins to activate diverse intracellular signaling pathways in mouse hippocampus: role in neuronal excitability and associative learning

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    Corticotropin-releasing factor (CRF) exerts a key neuroregulatory control on stress responses in various regions of the mammalian brain, including the hippocampus. Using hippocampal slices, extracts, and whole animals, we investigated the effects of human/rat CRF (h/rCRF) on hippocampal neuronal excitability and hippocampus-dependent learning in two mouse inbred strains, BALB/c and C57BL/6N. Intracellular recordings from slices revealed that application of h/rCRF increased the neuronal activity in both mouse inbred strains. Inhibition of protein kinase C (PKC) by bisindolylmaleimide I (BIS-I) prevented the h/rCRF effect only in hippocampal slices from BALB/c mice but not in slices from C57BL/6N mice. Inhibition of cAMP-dependent protein kinase (PKA) by H-89 abolished the h/rCRF effect in slices from C57BL/6N mice, with no effect in slices from BALB/c mice. Accordingly, h/rCRF elevated PKA activity in hippocampal slices from C57BL/6N mice but increased only PKC activity in the hippocampus of BALB/c mice. These differences in h/rCRF signal transduction were also observed in hippocampal membrane suspensions from both mouse strains. In BALB/c mice, hippocampal CRF receptors coupled to Gq/11 during stimulation by h/rCRF, whereas they coupled to Gs, Gq/11, and Gi in C57BL/6N mice. As expected on the basis of the slice experiments, h/rCRF improved context-dependent fear conditioning of BALB/c mice in behavioral experiments, and BIS-I prevented this effect. However, although h/rCRF increased neuronal spiking in slices from C57BL/6N mice, it did not enhance conditioned fear. These results indicate that the CRF system activates different intracellular signaling pathways in mouse hippocampus and may have distinct effects on associative learning depending on the mouse strain investigated

    H. W. Spiess - An Appreciation

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    Capt. W. H. Graves

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    Engraving of Captain W. H. Graves who was an attorney, businessman and author in Birmingham, Alabama. He wrote the book titled: Junius Finally Discovered

    Precipitation of supersaturated solute in H ion irradiated Fe-Au and Fe-Au-W alloys studied by positron annihilation spectroscopy

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    The effect of thermal aging of homogenized Fe-Au and Fe-Au-W alloys, irradiated at room temperature with hydrogen ions, was studied for an aging treatment at 300 °C for aging times up to 100 h. The aging behavior of the Fe-based alloys is compared to the results for pure Fe. The precipitation behavior of Au-rich and W-rich precipitates and its correlation to the H+ irradiation-induced defects is investigated by variable energy positron annihilation spectroscopy (VEPAS). The formation of open-volume defects after irradiation is monitored by an increase in the S parameter, while the recovery of the vacancy-like defects and the formation of precipitates are signalled by an increase in the W parameter. Au-rich precipitation continuously develops during long-term aging, as indicated by the increase in the W parameter. The change of the W parameter in the Fe-Au-W alloy is not only due to the effect of solute W on the Au precipitates, but also because of the interface of W-rich Laves phase with matrix.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Novel Aerospace MaterialsRST/Fundamental Aspects of Materials and Energ

    Geometry of Complex Molecular Motions of Guest Molecules in Polymers from Solid State H-2 NMR

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    Nanoporous systems provide interesting possibilities to confine molecules to be used for specific functions, e.g., as switches, in sensorics, or in separation. Such behavior partially mimics biological systems, where enzymes with specific cavities exhibit exquisite binding discrimination and reactivity.1d,1e Recent advances in solid-state inclusion compounds produced an extraordinary variety of cavities that encapsulate guests through noncovalent forces and can be customized through molecular design to control their solid-state properties and guest reactivity. Crystalline polymers offer the additional advantage of processability and alignment due tomechanical forces. In this context, the nanoporous δ and ε crystalline phases of syndiotactic polystyrene (s-PS), obtained by guest removal with supercritical carbon dioxide from cocrystalline phase, offer promising applications in chemical separation (mainly air/water purification), in sensorics, and optical applications

    Lydia H. Hart Diary

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    Diary, 1823-1830, 1875 and loose papers 1813, 1831, and undated of Lydia H. Hart of Richmond, Virginia and later Walden, Orange County, New York. The Diary was started by Lydia H. Hart, the wife of Reverend William H. Hart, who was the rector of St. John’s Church in Richmond, VA and later St. Andrews Church in Walden, New York. Diary entries include day-to-day activities and meetings with local neighbors and church patron’s. These neighbors included Elizabeth Van Lew and her parents, which Lydia Hart writes about several times. Most dated entries also include discussion of specific bible verses or Rev. Hart’s sermons. Notable entries include a description of the funeral service for Rev. John Buchanan, former rector of St. John’s Church from 1795 to 1822. Diary entries are chronological and more frequent for 1823 and become less frequent in 1823. In 1828, Lydia Hart moved to New York and eventually to Walden, New York in May 1830.At the end of the diary entries is an entry form another author, possibly by Mary. W. Hart dated 1875. Lydia Hart died in 1831 and could not have made the entry.At the back of the diary and upside down to the diary entries are transcriptions of letters and poems of Lydia Hart’s to various newspapers and and personnel correspondence. Entries include a plea for support to the city of Richmond to take care of its ‘destitute children’, letters to the editor of local newspapers, and poems for the birth of a child or death of a patron.Loose papers include a letter dated Jan 8th 1813, a bequeath request from William H. Hart for the placement of a Tombstone for Lydia Hart, a table of contents for various letters or sermons, a letter from William Hart to a friend from Richmond, and 2 loose undated papers of unknown authorship. The letter from William Hart speaks of the events of Lydia’s death, and inquiries about events taking place in Richmond

    1, 2-H shift in benzylchlorocarbene: isotope effect and influence of the solvent

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    Laser flash photolysis of 3-chloro-3-benzyldiazirine and 3-chloro-3-(phenyldideuteriomethyl)diazirine in isooctane over the 60 to -80-degrees-C temperature range gives rise to curved Arrhenius plots for both 1,2-H and 1,2-D migration in benzylchlorcarbene. The k(H)/k(D) values increase smoothly from 0.87 to 2.62 when the temperature increases from -60 to +30-degrees-C. The k(H)/k(D) value is approximately 4 for most of the temperatures studied if a solvent correction is applied. Quantum mechanical tunnelling or the influence of the solvent may be a possible explanation for these observations.PT: J; CR: BONNEAU R, 1989, J AM CHEM SOC, V111, P5973 BONNEAU R, 1992, J PHOTOCH PHOTOBIO A, V68, P97 DIX EJ, 1993, J AM CHEM SOC, V115, P10424 EVANSECK JD, 1990, J PHYS CHEM-US, V94, P5518 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 JACKSON JE, 1994, ADV CARBENE CHEM JONES M, 1980, REACTIVE INTERMEDIAT, V2 KIRMSE W, 1971, CARBENE CHEM LIU MTH, 1984, TETRAHEDRON, V40, P887 LIU MTH, 1990, J AM CHEM SOC, V112, P3915 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LIU MTH, 1992, J PHYS ORG CHEM, V15, P285 LIU MTH, 1994, RES CHEM INTERMEDIAT, V20, P195 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MOSS RA, 1992, TETRAHEDRON LETT, V33, P4287 MOSS RA, 1994, ADV CARBENE CHEM MUROV SL, 1973, HDB PHOTOCHEMISTRY NICKON A, 1993, ACCOUNTS CHEM RES, V26, P84 SALIS GA, 1968, J PHYS CHEM-US, V72, P752 SANDER W, 1994, UNPUB SCHAEFER HF, 1979, ACCOUNTS CHEM RES, V12, P288 SCHOLLER WW, 1989, HOUBEN WEYL METHODEN, P41 SHIMANOUCHI T, 1972, TABLES MOL VIBRATION, V1 SUGIYAMA MH, 1992, J AM CHEM SOC, V114, P966 WIERLACHER S, 1993, J AM CHEM SOC, V115, P8943; NR: 25; TC: 20; J9: J PHOTOCHEM PHOTOBIOL A-CHEM; PG: 5; GA: PV021Source type: Electronic(1
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