Investigation of the thermal tolerance of silicon-based lateral spin valves.

Improvement in the thermal tolerance of Si-based spin devices is realized by employing thermally stable nonmagnetic (NM) electrodes. For Au/Ta/Al electrodes, intermixing between Al atoms and Au atoms occurs at approximately 300 °C, resulting in the formation of a Au/Si interface. The Au-Si liquid phase is formed and diffuses mainly along an in-plane direction between the Si and AlN capping layers, eventually breaking the MgO layer of the ferromagnetic (FM) metal/MgO electrodes, which is located 7 µm away from the NM electrodes. By changing the layer structure of the NM electrode from Au/Ta/Al to Au/Ta, the thermal tolerance is clearly enhanced. Clear spin transport signals are obtained even after annealing at 400 °C. To investigate the effects of Mg insertion in FM electrodes on thermal tolerance, we also compare the thermal tolerance among Fe/Co/MgO, Fe/Co/Mg/MgO and Fe/Co/MgO/Mg contacts. Although a highly efficient spin injection has been reported by insertion of a thin Mg layer below or above the MgO layer, these thermal tolerances decrease obviously.

Monolayer MoS2 field effect transistor with low Schottky barrier height with ferromagnetic metal contacts.

Two-dimensional MoS2 has emerged as promising material for nanoelectronics and spintronics due to its exotic properties. However, high contact resistance at metal semiconductor MoS2 interface still remains an open issue. Here, we report electronic properties of field effect transistor devices using monolayer MoS2 channels and permalloy (Py) as ferromagnetic (FM) metal contacts. Monolayer MoS2 channels were directly grown on SiO2/Si substrate via chemical vapor deposition technique. The increase in current with back gate voltage (Vg) shows the tunability of FET characteristics. The Schottky barrier height (SBH) estimated for Py/MoS2 contacts is found to be +28.8 meV (at Vg = 0V), which is the smallest value reported so-far for any direct metal (magnetic or non-magnetic)/monolayer MoS2 contact. With the application of positive gate voltage, SBH shows a reduction, which reveals ohmic behavior of Py/MoS2 contacts. Low SBH with controlled ohmic nature of FM contacts is a primary requirement for MoS2 based spintronics and therefore using directly grown MoS2 channels in the present study can pave a path towards high performance devices for large scale applications.

Acute leukemia during pregnancy: an investigative survey of the past 11 years.

INTRODUCTION: The management of pregnant women with acute leukemia is usually challenging. We collected data concerning pregnant women with acute leukemia in the Kanagawa area in Japan. METHODS: A questionnaire was sent to 24 institutions in the Kanagawa area. RESULTS: Data were obtained for 11 patients, median age of 31 years (range, 20-36). Eight patients had acute myeloid leukemia and three had acute lymphoblastic leukemia. Six patients were diagnosed in the first trimester of pregnancy, one in the second trimester, and four in the third trimester. Five of six patients diagnosed in the first trimester had abortions before chemotherapy, and one had an elective abortion after receiving chemotherapy. All patients diagnosed in the second or third trimester delivered live infants. Of the six patients diagnosed in the first trimester, two died of recurrent leukemia, and four remained in remission. Of the five patients diagnosed in the second or third trimester, four achieved complete remission and remained in remission. One patient died of sepsis 4 days after cesarean section. CONCLUSIONS: Careful surveillance and monitoring of the fetus and close co-operation among hematologists, gynecologists, and pediatricians are essential to successfully treat pregnant women with acute leukemia.

Adjuvant radiotherapy to an initial bulky mass in diffuse large B-cell lymphoma: lack of survival benefit.

The role of adjuvant radiotherapy to the site of the initial bulky mass in lymphoma remains to be determined. We retrospectively analyzed clinical data for 35 consecutive patients with diffuse large B-cell lymphoma who had an initial bulky mass were treated successfully by chemotherapy reaching complete remission or complete remission unconfirmed according to International Workshop Criteria. Median age was 57 years. Median follow-up period for surviving patients after completion of chemotherapy was 45 months. Twenty patients (group A) received adjuvant radiotherapy to the bulky mass, while 15 (group B) did not. Median dose of radiation in group A was 40 Gy (range, 30-60 Gy). In group A, four relapses occurred, all from other sites; group B included three relapses from bulky and one from other sites. Overall survival (P = 0.15) and recurrence-free survival (P = 0.48) did not differ significantly between groups. Although adjuvant radiotherapy to the initial bulky site is useful for controlling local disease, no survival benefit was seen.

Anti-cancer activities of pyrazolo[1,5-a]indole derivatives.

The structure activity relationship (SAR) in the anti-cancer activities of pyrazolo[1,5-a]indole derivatives was investigated, and the following conclusions were obtained: 1) N(1)-quaternarization is essential for anti-cancer activity, 2) the size and polarity of the 2-substituent is crucial for in vitro activity which allows further investigation in an in vivo test, 3) the effect of the 4-substituent on the activity is minor compared with the other two factors.