4ff electron temperature driven ultrafast electron localization

Valence transitions in strongly correlated electron systems are caused by orbital hybridization and Coulomb interactions between localized and delocalized electrons. The transition can be triggered by changes in the electronic structure and is sensitive to temperature variations, applications of magnetic fields, and physical or chemical pressure. Launching the transition by photoelectric fields can directly excite the electronic states and thus provides an ideal platform to study the correlation among electrons on ultrafast timescales. The EuNi$_2$(Si$_{0.21}$Ge$_{0.79}$)$_2$ mixed-valence metal is an ideal material to investigate the valence transition of the Eu ions via the amplified orbital hybridization by the photoelectric field on sub-picosecond timescales. A direct view on the 4$f$ electron occupancy of the Eu ions is required to understand the microscopic origin of the transition. Here we probe the 4$f$ electron states of EuNi$_2$(Si$_{0.21}$Ge$_{0.79}$)$_2$ at the sub-ps timescale after photoexcitation by X-ray absorption spectroscopy across the Eu $M_5$-absorption edge. The observed spectral changes due to the excitation indicate a population change of total angular momentum multiplet states $J$ = 0, 1, 2, and 3 of Eu$^{3+}$, and the Eu$^{2+}$ $J$ = 7/2 multiplet state caused by an increase in 4$f$ electron temperature that results in a 4$f$ localization process. This electronic temperature increase combined with fluence-dependent screening accounts for the strongly non-linear effective valence change. The data allow us to extract a time-dependent determination of an effective temperature of the 4$f$ shell, which is also of great relevance in the understanding of metallic systems' properties, such as the ultrafast demagnetization of ferromagnetic rare-earth intermetallics and their all-optical magnetization switching.Comment: 19 pages, 9 figure

Electronic structure of Kondo lattice compounds YbNi3X9 (X = Al, Ga) studied by hard x-ray spectroscopy

We have performed hard x-ray photoemission spectroscopy (HAXPES) for Yb-based Kondo lattice compounds; an antiferromagnetic heavy-fermion system YbNi3Al9 and a valence fluctuation system YbNi3Ga9. The Yb 3d5/2 spectra of YbNi3Ga9 showed both Yb2+ and Yb3+-derived structures indicating strong valence fluctuation, and the intensity of Yb2+ (Yb3+) structures gradually increased (decreased) on cooling. The Yb 3d5/2 spectra of YbNi3Al9 mostly consisted of Yb3+-derived structures and showed little temperature dependence. The Yb valences of YbNi3Ga9 and YbNi3Al9 at 22 K were evaluated to be 2.43 and 2.97, respectively. Based on the results of the Ni 2p and valence-band HAXPES spectra together with soft x-ray valence-band spectra, we described that the difference of physical properties of YbNi3X9 (X= Al, Ga) is derived from the differences of the 4f-hole level relative to the Fermi level (EF) and Ni 3d density of states at EF. The HAXPES results on the Yb valences were consistent with those obtained by x-ray absorption spectroscopy using the partial fluorescence yield mode and resonant x-ray emission spectroscopy at the Yb L3 edge

Successful management of refractory pleural effusion due to systemic immunoglobulin light chain amyloidosis by vincristine adriamycin dexamethasone chemotherapy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Refractory pleural effusion in systemic immunoglobulin light chain amyloidosis without cardiac decompensation is rarely reported and has a poor prognosis in general (a median survival of 1.6 months). Moreover, the optimum treatment for this condition is still undecided. This is the first report on the successful use of vincristine, adriamycin and dexamethasone chemotherapy for refractory pleural effusion due to systemic immunoglobulin light chain amyloidosis without cardiac decompensation.</p> <p>Case presentation</p> <p>We report the case of a 68-year old Japanese male with systemic immunoglobulin light chain amyloidosis presenting with bilateral pleural effusion (more severe on the right side) in the absence of cardiac decompensation that was refractory to diuretic therapy. The patient was admitted for fatigue, exertional dyspnea, and bilateral lower extremity edema. He had been receiving intermittent melphalan and prednisone chemotherapy for seven years. One month before admission, his dyspnea had got worse, and his chest radiograph showed bilateral pleural effusion; the pleural effusion was ascertained to be a transudate. The conventionally used therapeutic measures, including diuretics and thoracocentesis, failed to control pleural effusion. Administration of vincristine, adriamycin, and dexamethasone chemotherapy led to successful resolution of the effusion.</p> <p>Conclusion</p> <p>Treatment with vincristine, adriamycin, and dexamethasone chemotherapy was effective for the refractory pleural effusion in systemic immunoglobulin light chain amyloidosis without cardiac decompensation and appears to be associated with improvement in our patient's prognosis.</p

Conduction-band electronic states of YbInCu4 studied by photoemission and soft x-ray absorption spectroscopies

We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCu4 by means of temperature-dependent hard x-ray photoemission spectroscopy (HX-PES) of the Cu 2p3/2 and In 3d5/2 core states taken at hν=5.95 keV, soft x-ray absorption spectroscopy (XAS) of the Cu 2p3/2 core absorption region around hν∼935 eV, and soft x-ray photoemission spectroscopy (SX-PES) of the valence band at the Cu 2p3/2 absorption edge of hν=933.0 eV. With decreasing temperature below the valence transition at TV=42 K, we have found that (1) the Cu 2p3/2 and In 3d5/2 peaks in the HX-PES spectra exhibit the energy shift toward the lower binding-energy side by ∼40 and ∼30 meV, respectively, (2) an energy position of the Cu 2p3/2 main absorption peak in the XAS spectrum is shifted toward higher photon-energy side by ∼100 meV, with an appearance of a shoulder structure below the Cu 2p3/2 main absorption peak, and (3) an intensity of the Cu L3VV Auger spectrum is abruptly enhanced. These experimental results suggest that the Fermi level of the CB-derived density of states is shifted toward the lower binding-energy side. We have described the valence transition in YbInCu4 in terms of the charge transfer from the CB to Yb 4f states

希薄磁性半導体Cd_<1-x>Mn_xTeの真空紫外光電子・逆光電子分光

Valence-band and conduction-band densities of states (DOS's) of Cd1-xMnxTe epitaxial films (0 ≤ x ≤ 0.7) have been investigated by means of in situ measurements of ultraviolet photoemission and inverse-photoemission spectroscopies (UPS and IPES). Based on one-electron band theory, features observed at -3.4 and 3.6 eV relative to the valence-band maximum (VBM) are ascribed to emission from the Mn 3d↑ and 3d↓ states with eg symmetry, respectively, providing a Mn 3d spin-exchange splitting energy (Ueff) of 7.0±0.2 eV. This value compares well with the value predicted in the theoretical investigation of electronic structures and magnetic properties of Cd1-xMnxTe. With increasing Mn concentration, the energy position of the conduction-band minimum shifts almost linearly toward higher energy relative to the VBM as a result of an increasing contribution of the higher-lying Mn 4s level relative to the Cd 5s level. Mn 3d partial DOS's in the valence-band region of Cd1-xMnxTe have been determined from resonant photoemission spectroscopy in the Mn 3p-3d core excitation region. The partial DOS's reveal an appreciable contribution of the Mn 3d states to the top 9 eV of valence bands with three structures; valence bands at 0~-2.5 eV, a main peak at -3.4 eV and a multielectron satellite at -5~-9 eV. These features are almost independent of the Mn concentration. Apart from one-electron band theory, the whole spectrum including the multielectron satellite is found to be well reproduced in terms of the configuration interaction theory using a Mn2+(Te2-)4 model cluster. Electronic structures of zinc-blende MnTe epitaxial films have also been investigated by means of UPS and IPES. The Ueff-value of zinc-blende MnTe is in good agreement with those of Cd1-xMnxTe and Zn 1-xMnxTe. The width of valence bands and Ueff are by 1.3 eV narrower and by 0.3 eV larger than those of NiAs-type MnTe, respectively.Contents Abstract / p1 Chapter1.Introduction / p2 　References / p7 Chapter2.General description of photoemission and inverse-photoemission spectroscopies / p10 　2-1.Photoemission spectroscopy / p10 　2-2.Inverse-photoemission spectroscopy / p13 　References / p17 Chapter3.Hot wall epitaxy(HWE) / p18 　3-1.HWE method / p18 　3-2.Details of the HWE apparatus for DMS / p20 　References / p28 Chapter4.Experimental details I:ultraviolet photoemission and inverse-photoemission study / p29 　4-1.Ultraviolet photoemission and inverse-photoemission spectrometers / p29 　4-2.Sample preparation / p33 　References / p45 Chapter5.Experimental details II:Resonant photoemission spectroscopy / p47 　5-1.Photoemission measurements at SOR-RING / p47 　5-2.Sample preparation / p47 　References / p49 Chapter6.Results and discussion / p50 　6-1.Photoemission and inverse-photoemission study of Cd1-xMnxTe / p50 　6-2.Photoemission and inverse-photoemission study of zinc-blende MnTe / p71 　References / p77 Chapter7 Conclusion / p80 Acknowledgments / p82広島大学(Hiroshima University)博士(理学)Physical Sciencedoctora

Essentiality of Nfatc1 short isoform in osteoclast differentiation and its self-regulation

Abstract During osteoclast differentiation, the expression of the transcription factor nuclear factor of activated T cell 1 (Nfatc1) increases in an autoproliferative manner. Nfatc1 isoforms are of three sizes, and only the short isoform increases during osteoclast differentiation. Genetic ablation of the whole Nfatc1 gene demonstrated that it is essential for osteoclastogenesis; however, the specific role of the Nfatc1 short form (Nfatc1/αA) remains unknown. In this study, we engineered Nfatc1 short form-specific knockout mice and found that these mice died in utero by day 13.5. We developed a novel osteoclast culture system in which hematopoietic stem cells were cultured, proliferated, and then differentiated into osteoclasts in vitro. Using this system, we show that the Nfatc1/αA isoform is essential for osteoclastogenesis and is responsible for the expression of various osteoclast markers, the Nfatc1 short form itself, and Nfatc1 regulators

Osteomyelitis due to methicillin-resistant successfully treated by an oral combination of minocycline and trimethoprim–sulfamethoxazole

Most of the anti-methicillin-resistant Staphylococcus aureus drugs available in Japan are administered intravenously, except for linezolid, which can also be administered orally. Here, we report a lupus patient with methicillin-resistant S. aureus– induced osteomyelitis. Linezolid had to be stopped due to severe anemia. In an effort to treat her on an outpatient basis, we planned to use a combination of minocycline and trimethoprim–sulfamethoxazole that exhibited in vitro sensitivity against the methicillin-resistant S. aureus detected, and rifampicin is used against methicillin-resistant S. aureus in certain cases. The use of rifampicin increased the level of C-reactive protein even though the prednisolone dose used was doubled, so we gave up using it. The combined application of oral minocycline and trimethoprim–sulfamethoxazole, however, controlled the inflammation, and the patient was able to be discharged. Fourteen months later, we discontinued the administration of both drugs and there has been no relapse more than a year. This combination of antibiotics may be useful, especially when patients want to be treated on an outpatient basis