Magnetic field effects on two-dimensional Kagome lattices

Magnetic field effects on single-particle energy bands (Hofstadter butterfly), Hall conductance, flat-band ferromagnetism, and magnetoresistance of two-dimensional Kagome lattices are studied. The flat-band ferromagnetism is shown to be broken as the flat-band has finite dispersion in the magnetic field. A metal-insulator transition induced by the magnetic field (giant negative magnetoresistance) is predicted. In the half-filled flat band, the ferromagnetic-paramagnetic transition and the metal-insulator one occur simultaneously at a magnetic field for strongly interacting electrons. All of the important magnetic fields effects should be observable in mesoscopic systems such as quantum dot superlattices.Comment: 10 pages, 4 figures, and 1 tabl

Preparation of β-sialon from Silica-gel

To prepare β-sialon (Si_2Al_4O_4N_4) through alumino-thermite reaction, white silica-gel with amorphous structure was reacted with aluminum at 1400℃ to 1800℃ for 0.5 to 4.0h under nitrogen gas flow. The molar ratio of SiO_2 to Al was 12 : 16 and cobalt of 8 mass% against white silica-gel was added as a reaction promoter. Sialon (Si_Al_zO_zN_) with the z-value ranging from 2.5 to 4.0 was formed at 1400℃ and 1600℃. Aluminum compounds such as α-Al_2O_3,AIN and others were formed along with sialon at these temperatures. The reason why many aluminum compounds were formed is considered to be caused by volatilization of silicon as SiO gas. On the other hand, Al_2O_3・AIN spinel and AIN were formed at 1800℃, except sialon

A CASE OF REPLACEMENT OF THE ABDOMINAL AORTIC ANEURYSM

This is a report on a case of successful replacement of abdominal aortic aneurysm with a crimped Dacron graft. The prognosis of such a disease is said to be very poor, and it is generally accepted that a surgical replacment of the aneurysm is the only reliable treatment at present. Therefore the importance of early diagnosis and surgery must be stressed

Flat-band ferromagnetism in quantum dot superlattices

Possibility of flat-band ferromagnetism in quantum dot arrays is theoretically discussed. By using a quantum dot as a building block, quantum dot superlattices are possible. We consider dot arrays on Lieb and kagome lattices known to exhibit flat band ferromagnetism. By performing an exact diagonalization of the Hubbard Hamiltonian, we calculate the energy difference between the ferromagnetic ground state and the paramagnetic excited state, and discuss the stability of the ferromagnetism against the second nearest neighbor transfer. We calculate the dot-size dependence of the energy difference in a dot model and estimate the transition temperature of the ferromagnetic-paramagnetic transition which is found to be accessible within the present fabrication technology. We point out advantages of semiconductor ferromagnets and suggest other interesting possibilities of electronic properties in quantum dot superlattices.Comment: 15 pages, 7 figures (low resolution). High-resolution figures are available at http://www.brl.ntt.co.jp/people/tamura/Research/PublicationPapers.htm

The BBB disruption was restored after adding GM6001 or a neutralizing anti-VEGF antibody to the sera from relapsing MS patients.

<p>(A)–(J) The effects of TNF-α, IFN-γ, IL-17 or VEGF neutralizing antibodies or a matrix- metalloproteinases (MMPs) inhibitor, GM6001, on the amount of tight junction proteins in TY09 cells after exposure to the sera from SPMS or RRMS-R patients was determined by a Western blot analysis. (K)–(N) Each bar graph reflects the combined densitometry data from each independent experiment (mean±SEM, SPMS n = 6, RRMS-R n = 4). (M) In patients with RRMS-R, preincubation with a VEGF neutralizing antibody or GM6001 increased the amount of claudin-5 protein in TY09 cells. Part 2 (O) The TEER value of the TY09 cells significantly increased after incubation with the sera from RRMS-R patients that had been pretreated with an anti-VEGF neutralizing antibody or GM 6001 (mean±SEM, n = 6). SPMS: conditioned medium containing a 10% concentration of serum from a SPMS patient diluted with non-conditioned DMEM containing 10% FBS; SPMS+TNF-α Ab: conditioned medium with 10% SPMS sera pretreated with a TNF-α neutralizing antibody; SPMS+IFN-γ Ab: conditioned medium with 10% SPMS sera pretreated with an IFN-γ neutralizing antibody; SPMS+IL-17 Ab: conditioned medium with 10% SPMS sera pretreated with an IL-17 neutralizing antibody; SPMS+VEGF Ab: conditioned medium with 10% SPMS sera pretreated with a VEGF neutralizing antibody; SPMS+GM6001: conditioned medium with 10% SPMS sera pretreated with GM6001; RRMS-R: conditioned medium containing a 10% concentration of serum from a RRMS-R patient diluted with non-conditioned DMEM containing 10% FBS; RRMS-R+TNF-α Ab: conditioned medium with 10% RRMS-R sera pretreated with a TNF-α neutralizing antibody; RRMS-R+IFN-γ Ab: conditioned medium with 10% RRMS-R sera pretreated with an IFN-γ neutralizing antibody; RRMS-R+IL-17 Ab: conditioned medium with 10% RRMS-R sera pretreated with an IL-17 neutralizing antibody; RRMS-R+VEGF Ab: conditioned medium with 10% RRMS-R sera pretreated with a VEGF neutralizing antibody; RRMS-R+GM6001: conditioned medium with 10% RRMS-R sera pretreated with GM6001.</p

The effects of MS patients' sera on the tight junction proteins and adhesion molecules in TY09 cells.

<p>(A)–(D) The changes in the amounts of claudin-5, occludin and VCAM-1 in human brain microvascular endothelial cells, named “TY09 cells”, were determined after exposure to the sera from patients in the relapse phase of MS (RRMS-R), the stable phase of RRMS (RRMS-S) or secondary progressive MS (SPMS), or from healthy controls, as determined by a Western blot analysis. (E)(F)(G) Each bar graph reflects the combined densitometry data from each independent experiment (mean ± SEM, SPMS n = 8, RRMS-R n = 6, RRMS-S n = 9, Normal n = 6). (E)(F) The amount of claudin-5 protein in TY09 cells was significantly decreased after the exposure to sera from SPMS or RRMS-R patients, and the amount of occludin protein in TY09 cells was significantly reduced after exposure to sera from SPMS patients, whereas the amounts of the claudin-5 and occludin proteins were not significantly affected by exposure to sera from RRMS-S patients or healthy controls. (G) The amount of VCAM-1 was significantly increased after exposure to sera from RRMS-R, RRMS-S or SPMS patients (H) The TEER value of BMECs was significantly decreased after exposure to RRMS-R or SPMS sera, but was not influenced by exposure to sera from RRMS-S patients or healthy controls (mean±SEM, SPMS n = 8, RRMS-R n = 6, RRMS-S n = 9, Normal n = 6). Control: non-conditioned DMEM containing 20% FBS; SPMS: conditioned medium with 10% serum from an SPMS patient diluted with non-conditioned DMEM containing 10% FBS; RRMS-R: conditioned medium with a 10% concentration of serum from an RRMS-R patient diluted with non-conditioned DMEM containing 10% FBS; RRMS-S: conditioned medium with a 10% concentration of serum from an RRMS-S patient diluted with non-conditioned DMEM containing 10% FBS; Normal: conditioned medium with 10% serum from a healthy control diluted with non-conditioned medium of DMEM containing 10% FBS.</p