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- Abdeldaim, Aly, 1993, et al.
(författare)
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Large easy-axis anisotropy in the one-dimensional magnet BaMo(PO4)(2)
- 2019
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9969 .- 2469-9950. ; 100:21
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Tidskriftsartikel (refereegranskat)abstract
- We present an extensive experimental and theoretical study on the low-temperature magnetic properties of the monoclinic anhydrous alum compound BaMo(PO4)(2). The magnetic susceptibility reveals strong antiferromagnetic interactions theta(CW) = -167 K and long-range magnetic order at T-N = 22 K, in agreement with a recent report. Powder neutron diffraction furthermore shows that the order is collinear, with the moments near the ac plane. Neutron spectroscopy reveals a large excitation gap Delta = 15 meV in the low-temperature ordered phase, suggesting a much larger easy-axis spin anisotropy than anticipated. However, the large anisotropy justifies the relatively high ordered moment, Neel temperature, and collinear order observed experimentally and is furthermore reproduced in a first-principles calculations by using a new computational scheme. We therefore propose BaMo(PO4)(2) to host S = 1 antiferromagnetic chains with large easy-axis anisotropy, which has been theoretically predicted to realize novel excitation continua.
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| 2. |
- Ammoun, Sylwia, et al.
(författare)
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OX1 orexin receptors activate extracellular signal-regulated kinase in Chinese hamster ovary cells via multiple mechanisms : the role of Ca2+ influx in OX1 receptor signaling
- 2006
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 20:1, s. 80-99
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Tidskriftsartikel (refereegranskat)abstract
- Activation of OX1 orexin receptors heterologously expressedin Chinese hamster ovary (CHO) cells led to a rapid, strong,and long-lasting increase in ERK phosphorylation (activation).Dissection of the signal pathways to ERK using multiple inhibitorsand dominant-negative constructs indicated involvement of Ras,protein kinase C, phosphoinositide-3-kinase, and Src. Most interestingly,Ca2+ influx appeared central for the ERK response in CHO cells,and the same was indicated in recombinant neuro-2a cells andcultured rat striatal neurons. Detailed investigations in CHOcells showed that inhibition of the receptor- and store-operatedCa2+ influx pathways could fully attenuate the response, whereasinhibition of the store-operated Ca2+ influx pathway alone orthe Ca2+ release was ineffective. If the receptor-operated pathwaywas blocked, an exogenously activated store-operated pathwaycould take its place and restore the coupling of OX1 receptorsto ERK. Further experiments suggested that Ca2+ influx, as such,may not be required for ERK phosphorylation, but that Ca2+,elevated via influx, acts as a switch enabling OX1 receptorsto couple to cascades leading to ERK phosphorylation, cAMP elevation,and phospholipase C activation. In conclusion, the data suggestthat the primary coupling of orexin receptors to Ca2+ influxallows them to couple to other signal pathways; in the absenceof coupling to Ca2+ influx, orexin receptors can act as signalintegrators by taking advantage of other Ca2+ influx pathways.
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