Amorphization by Compound-Element Milling in Al- TM(TM=Mn, Fe, Co and Ni) Binary System

A compound-element milling process was employed to fabricate Al-based amorphous alloys. Amorphous phases with a blend composition of Al_Co_ and Al_Mn_ were obtained by mechanical alloying (MA) for the mixture of Al and monoclinic Al_Co_4 powders and Al and orthorhombic Al_Mn_4 powders which could not be obtained by milling Al and Co or Mn elemental powders. Avail of the MA from the compound and element is due to the enhancement of efficiency during milling by leaving out the welding and supressing the agglomeration of the powders in the process. Mechanism of the amorphization were discussed together with mechanical grinding of the compound. We assert that the MA of Al and its compounds is a available process to produce amorphous phases in Al-enriched(Al>85 at%) alloys

Photoemission Study of Icosahedral Al_<70>Pd_<20>Mn_<10>

Measurements with photoemission spectroscopy in the photonenergy range 35-150 eV have been used to measure the valence band of the stable icosahedral Al_Pd_Mn_. The maxima of the Pd 4d- and Mn 3d derived states are respectively at 3.6 and 0.7 eV below the Fermi level. The strong decrease of intensity towards the Fermi level is interpreted as evidence for the presence of a pseudogap at the Fermi level. No unusual features in the valence band of icosahedral Al_Pd_Mn_, which could be ascribed to its quasiperiodic nature, are observed within the resolution of the experiment

Mirtazapine exerts an anxiolytic-like effect through activation of the median raphe nucleus-dorsal hippocampal 5-HT pathway in contextual fear conditioning in rats

The functional role of serotonergic projections from the median raphe nucleus (MRN) to the dorsal hippocampus (DH) in anxiety remains understood poorly. The purpose of the present research was to examine the functional role of this pathway, using the contextual fear conditioning (CFC) model of anxiety. We show that intra-MRN microinjection of mirtazapine, a noradrenergic and specific serotonergic antidepressant, reduced freezing in CFC without affecting general motor activity dose-dependently, suggesting an anxiolytic-like effect. In addition, intra-MRN microinjection of mirtazapine dose-dependently increased extracellular concentrations of serotonin (5-HT) but not dopamine in the DH. Importantly, intra-DH pre-microinjection of WAY-100635, a 5-HT1A antagonist, significantly attenuated the effect of mirtazapine on freezing. These results, for the first time, suggest that activation of the MRN-DH 5-HT1A pathway exerts an anxiolytic-like effect in CFC. This is consistent with the literature that the hippocampus is essential for retrieval of contextual memory and that 5-HT1A receptor activation in the hippocampus primarily exerts an inhibitory effect on the neuronal activity

MicroRNAs in lung cancer

Lung cancer (LC) is a serious public health problem responsible for the majority of cancer deaths and comorbidities in developed countries. Tobacco smoking is considered the main risk factor for LC; however, only a few smokers will be affected by this cancer. Current screening methods are focused on identifying the early stages of this malignancy. Thus, new data concerning the roles of microRNA alterations in inflammation, epithelial-mesenchymal transition and lung disease have increased hope about LC pathogenesis, diagnosis, treatment and prognosis. MicroRNA mechanisms include angiogenesis promotion, cell cycle regulation by modulating cellular proliferation and apoptosis, and migration and invasion inhibition. In this context, this manuscript reviews the current information about many important microRNAs as they relate to the initiation and progression of LC.info:eu-repo/semantics/publishedVersio

Production of Amorphous Alloy Balloons by Utilizing Viscous Flowability

This paper deals with the first example for the production of an amorphous alloy balloon with a height of 30 mm by blowing at 510 K an amorphous La_Al_Ni_ disk with a diameter of 35 mm and a thickness of 2.2 mm prepared by a metallic mold casting process. The blowing deformation utilizes the significant viscous flowability in the supercooled liquid region obtained by the transition from the amorphous solid. The key point which enables the blowing deformation is attributed to the finding that the La-Al-Ni amorphous alloy has a wide supercooled liquid region reaching 70 K before crystallization and has a high thermal stability against crystallization even in very low viscous state ranging from 10^6 to 10^7 Pa.s

Formation, Thermal Stability and Mossbauer Effect of Amorphous, Quasicrystalline and Crystalline Phases in Al-(Cu, Ni)-Fe Systems

Nonequilibrium phase including amorphous and bcc phases in Al-Cu-Fe and Al-Ni-Fe systems formed by sputtering method. The composition range of the formation phases are determined, in harmony with that of the binary Al-transition system. The composition range (Ni=10～15 at%, Fe=10～15 at%) of melt-quenched quasicrystalline phase is the formation region of an amorphous phase in a vapor quenched state. In the investigation for Al_Ni_Fe_ alloy, two exothermic peaks in calorimetric curves are observed during heating. The first peak is correlated with the precipitation of bcc-like nanocrystalline from vapor-quenched amorphous matrix, and the second peak is due to formation of decagonal phase. The Mossbauer spectra of these vapor-quenched nonequilibrium phases are examined and it is concluded that the local structure around Fe atom is similar among icosahedral, decagonal, amorphous and bcc phases

Atomic-scale structural identification and evolution of Co-W-C ternary SWCNT catalytic nanoparticles: High-resolution STEM imaging on SiO 2

International audienceRecently, W-based catalysts have provided a promising route to synthesize single-walled carbon nanotubes (SWCNTs) with specific chirality, but the mechanism of the growth selectivity is vaguely understood. We propose a strategy to identify the atomic structure as well as the structure evolution of the CoW -C ternary SWCNT catalyst. The key is to use a thin SiO 2 film as the catalyst support and observation window. As the catalyst is uniformly prepared on this SiO 2 film and directly used for the SWCNT synthesis, this method has an advantage over conventional methods: it creates an opportunity to obtain original, statistical, and dynamic understanding of the catalyst. As a technique, atomic-scale imaging directly on SiO 2 serves as a powerful and versatile tool to investigate nanocrystals and high-temperature reactions; for the synthesis of SWCNTs, this work successfully visualizes the structure and evolution of the catalyst and illuminates the possible nucleation sites of the chirality-specific growth

Penta-quark states with hidden charm and beauty

More and more hadron states are found to be difficult to be accommodated by the quenched quark models which describe baryons as 3-quark states and mesons as antiquark-quark states. Dragging out an antiquark-quark pair from the gluon field in hadrons should be an important excitation mechanism for hadron spectroscopy. Our recent progress on the penta-quark states with hidden charm and beauty is reviewed.Comment: Plenary talk at the 5th Asia-Pacific Conference on Few-Body Problems in Physics 2011 (APFB2011), 22-26 Aug., 2011, Seoul, Kore

Intrathecal delivery of PDGF produces tactile allodynia through its receptors in spinal microglia

Neuropathic pain is a debilitating pain condition that occurs after nerve damage. Such pain is considered to be a reflection of the aberrant excitability of dorsal horn neurons. Emerging lines of evidence indicate that spinal microglia play a crucial role in neuronal excitability and the pathogenesis of neuropathic pain, but the mechanisms underlying neuron-microglia communications in the dorsal horn remain to be fully elucidated. A recent study has demonstrated that platelet-derived growth factor (PDGF) expressed in dorsal horn neurons contributes to neuropathic pain after nerve injury, yet how PDGF produces pain hypersensitivity remains unknown. Here we report an involvement of spinal microglia in PDGF-induced tactile allodynia. A single intrathecal delivery of PDGF B-chain homodimer (PDGF-BB) to naive rats produced a robust and long-lasting decrease in paw withdrawal threshold in a dose-dependent manner. Following PDGF administration, the immunofluorescence for phosphorylated PDGF β-receptor (p-PDGFRβ), an activated form, was markedly increased in the spinal dorsal horn. Interestingly, almost all p-PDGFRβ-positive cells were double-labeled with an antibody for the microglia marker OX-42, but not with antibodies for other markers of neurons, astrocytes and oligodendrocytes. PDGF-stimulated microglia in vivo transformed into a modest activated state in terms of their cell number and morphology. Furthermore, PDGF-BB-induced tactile allodynia was prevented by a daily intrathecal administration of minocycline, which is known to inhibit microglia activation. Moreover, in rats with an injury to the fifth lumbar spinal nerve (an animal model of neuropathic pain), the immunofluorescence for p-PDGFRβ was markedly enhanced exclusively in microglia in the ipsilateral dorsal horn. Together, our findings suggest that spinal microglia critically contribute to PDGF-induced tactile allodynia, and it is also assumed that microglial PDGF signaling may have a role in the pathogenesis of neuropathic pain