The (FePt) 100Ϫx Cr x alloy thin films with xϭ0 -16 at. % were fabricated on natural-oxidized Si͑111͒ substrate by dc magnetron sputtering. The as-deposited films were annealed between 300 and 750°C in order to transform the soft magnetic fcc ␥-FePt phase to the hard magnetic fct ␥ 1 -FePt phase. The addition of Cr in the FePt thin films will reduce its saturation magnetization and coercivity, however, it could inhibit the grain growth during annealing of the samples. The optimum condition for high-density magnetic recording purpose of the (FePt) 100Ϫx Cr x alloy films was found with xϭ5 at. %, annealing at 650°C for 15 min, and ice water quench cooling. According to the transmission electron microscopy study, the average grain size in the annealed (FePt) 100Ϫx Cr x alloy thin films decrease from 60 to 5 nm with increasing x from 0 to 16.

Fe 100Ϫx Pt x alloy thin films with xϭ25-67 at. % were prepared by dc magnetron sputtering on naturally oxidized Si substrates. Effects of film composition, annealing temperature ͑300-650 °C͒, annealing time ͑5-120 min͒, and cooling rate ͑furnace cooling or ice water quench cooling͒ on the magnetic properties were investigated. Optimum conditions for saturation magnetization and coercivity of the Fe 100Ϫx Pt x alloy films were found with xϭ50 at.%, annealed at 600 °C for 30 min and cooled by ice water quenching. Our experimental data suggests that the magnetic hardening in Fe 100Ϫx Pt x alloy thin films is mainly due to the fct ␥ 1 -FePt phase and the domain wall pinning effect. The domain nucleation mechanism is dominated in samples with furnace cooling; the domain wall pinning mechanism dominates in samples cooled with ice water quenching.

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Hypothalamic neuropeptide Y (NPY) is a powerful orexigenic agent which plays critical roles in periodic eating behavior and maintenance of body weight (Wynne et al. 2005). Central administration of NPY can induce hyperphagia even under conditions of satiation, resulting in an increase of fat deposition, a decrease of energy expenditure, and a promotion of obesity (Williams et al. 2001). Phenylpropanolamine (PPA) is an over-the-counter anorectic drug that can be used in human dieters to reduce obesity (Schteingart 1992;Borovicka et al. 2002;Cooper et al. 2005). PPA is structurally and functionally related to amphetamine (AMPH)-like anorectic drugs, such as ephedrine, phentermine, diethylpropion, and methamphetamine, and is regarded as a sympathomimetic agent because of its Address correspondence and reprint requests to Dr Dong-Yih Kuo, Department of Physiology, Chung Shan Medical University, Taichung City 40201, Taiwan. E-mail: dykuo@csmu.edu.twAbbreviations used: AMPH, amphetamine; CART, cocaine-and amphetamine-regulated transcript; CREB, c-AMP response element binding protein; EMSA, electromobility shift assay; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; i.c.v., intracerebroventricular; NPY, neuropeptide Y; ODN, oligodeoxynucleotides; PKA, protein kinase A; PPA, phenylpropanolamine; SOD, superoxide dismutase. AbstractThe appetite-suppressing effect of phenylpropanolamine (PPA) has been attributed to its inhibitory action on neuropeptide Y (NPY), an appetite stimulant. However, molecular mechanisms underlying this effect are not clear. This study aimed to investigate if cAMP response element binding protein (CREB) signaling was involved. Moreover, possible role of superoxide dismutase-2 (SOD-2) during PPA treatment was also examined. Rats were daily treated with PPA for 4 days. Changes in hypothalamic NPY, protein kinase A, CREB, and SOD-2 mRNA contents were measured and compared. Results showed that protein kinase A, CREB, and SOD-2 mRNA levels increased during PPA treatment, which is concomitant with decreases in NPY and feeding. Moreover, CREB DNA binding activity detected by electromobility shift assay increased during PPA treatment, revealing an involvement of CREB-dependent gene transcription. Furthermore, infusions of CREB antisense oligonucleotide (or missense control) into cerebroventricle were performed at 1 h before daily PPA treatment in free-moving rats, and results showed that CREB knockdown could block PPA-induced anorexia and modify NPY and SOD-2 mRNA content toward normal. It is suggested that CREB signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of NPY gene expression and that an increase of SOD-2 may favor this modulation.

Effects of nitrogen contents and substrate temperatures to the microstructure and magnetic properties of the FeCoN films have been investigated. According to the TEM and x-ray Scherrer's equation analyses, we found that the grain size of films with substrate temperature below 200°C is roughly about 13 nm, however, it increases very fast for films with substrate temperature above 300°C. N content in the films is saturated to 30 at. %, as N 2 flow ratio N 2 /͑ArϩN 2 ) is higher than 5 vol. %. From the magnetization studies, we have found that the saturation magnetization 4M s of the optimum samples ͑with the substrate temperature near 200°C͒ is 23.9 kG. The improvement of the magnetic properties is attributed to the combination of ␣-Fe with N to form the high magnetic moment FeN phases.