Fundamental thickness limit of itinerant ferromagnetic SrRuO3_3 thin films

We report on a fundamental thickness limit of the itinerant ferromagnetic oxide SrRuO$_3$ that might arise from the orbital-selective quantum confinement effects. Experimentally, SrRuO$_3$ films remain metallic even for a thickness of 2 unit cells (uc), but the Curie temperature, T$_C$, starts to decrease at 4 uc and becomes zero at 2 uc. Using the Stoner model, we attributed the T$_C$ decrease to a decrease in the density of states (N$_o$). Namely, in the thin film geometry, the hybridized Ru-d$_yz,zx$ orbitals are terminated by top and bottom interfaces, resulting in quantum confinement and reduction of N$_o$.Comment: 20 pages, 4 figure

Durable remissions are rare following high dose therapy with autologous stem cell transplantation for adults with "paediatric" bone and soft tissue sarcomas

BACKGROUND: The role of high dose therapy (HDT) with autologous stem cell transplantation (AuSCT) for the treatment of bone and soft tissue sarcomas remains investigational. There are few reports examining this strategy focusing on the adult population. METHODS: We retrospectively reviewed our experience of adult patients undergoing HDT and AuSCT for 'paediatric' sarcomas. RESULTS: A total of 17 patients (14 male, 3 female) with median age at transplant of 24 years (range 20 – 41) were identified. The diagnosis was Ewings sarcoma/PNET (10), osteosarcoma (5) and rhabdomyosarcoma (2). Status prior to HDT, following conventional-dose chemotherapy +/- surgery +/- radiotherapy, was complete remission (CR) (6), partial remission (PR) (6), stable disease (1) and progressive disease (4). There was no transplant-related mortality. Two patients remain disease free beyond four years and both received HDT as part of their primary therapy (CR1 and PR1) however, the median progression free survival and overall survival following AuSCT for the entire cohort was only 7 months (range: 2–92 months) and 13 months (range: 2 – 92 months), respectively. CONCLUSION: HDT and AuSCT infrequently achieves prolonged remissions in adult patients and should only be considered in patients who are in a PR or CR following conventional-dose therapy. Further studies are required to define the role of HDT with AuSCT for adult patients with sarcoma

The Full Range of Predictions for B Physics From Iso-singlet Down Quark Mixing

We extend the range of predictions of the isosinglet (or vector) down quark model to the fully allowed physical ranges, and also update this with the effect of new physics constraints. We constrain the present allowed ranges of sin(2*beta) and sin(2*alpha), gamma, x_s, and A_{B_s}. In models allowing mixing to a new isosinglet down quark (as in E_6) flavor changing neutral currents are induced that allow a Z^0 mediated contribution to B-Bbar mixing and which bring in new phases. In (rho, eta), (x_s, sin(gamma)), and (x_s, A_{B_s}) plots for the extra isosinglet down quark model which are herein extended to the full physical range, we find new allowed regions that will require experiments on sin(gamma) and/or x_s to verify or to rule out an extra down quark contribution.Comment: 13 pages in RevTeX, 7 postscript figure

Lanczos exact diagonalization study of field-induced phase transition for Ising and Heisenberg antiferromagnets

Using an exact diagonalization treatment of Ising and Heisenberg model Hamiltonians, we study field-induced phase transition for two-dimensional antiferromagnets. For the system of Ising antiferromagnet the predicted field-induced phase transition is of first order, while for the system of Heisenberg antiferromagnet it is the second-order transition. We find from the exact diagonalization calculations that the second-order phase transition (metamagnetism) occurs through a spin-flop process as an intermediate step.Comment: 4 pages, 4 figure