This paper investigates the magnetoresistance of micron-sized MnAs/GaAs(AlAs)/MnAs magnetic tunnel junctions. We measure an asymmetric bias dependence of the magnetoresistance in which the negative ...contribution is attributed to resonant tunneling through a midgap defect band. Within this model we find a spin polarization of 60% for MnAs at the interface with GaAs. Moreover, we show that spin-dependent tunneling is a powerful technique for spectroscopic measurements of defects in a very thin layer.
We propose an analytical model of spin-dependent resonant tunneling through a 3D assembly of localized states (spread out in energy and in space) in a barrier. An inhomogeneous distribution of ...localized states leads to resonant tunneling magnetoresistance inversion and asymmetric bias dependence as evidenced with a set of experiments with MnAs/GaAs(7-10 nm)/MnAs tunnel junctions. One of the key parameters of our theory is a dimensionless critical exponent beta scaling the typical extension of the localized states over the characteristic length scale of the spatial distribution function. Furthermore, we demonstrate, through experiments with localized states introduced preferentially in the middle of the barrier, the influence of an homogeneous distribution on the spin-dependent transport properties.
A detailed investigation of the magnetic behavior of an ultrathin Fe film epitaxially grown onto MnAs/GaAs(001) is performed by means of both ferromagnetic resonance (FMR) and magneto-optical ...Kerr-effect (MOKE) experiments, as a function of temperature. When the MnAs underlayer is fully in the hexagonal ferromagnetic alpha phase (at low temperature) or in the orthorhombic non magnetic beta one (at high temperature), the magnetic behavior of the Fe film is found to be nearly the same and independent of the substrate. In contrast, at intermediate temperatures, when the MnAs underlayer presents a self-organized phase consisting of alpha-MnAs and beta-MnAs striped domains, the Fe film is strongly influenced by the dipolar (stray) fields arising from the substrate. As a consequence, the Fe film breaks in two distinct families of striped domains. Theoretical analysis of the FMR data in the whole investigated temperature range is performed using a free-energy density model which provides an accurate determination of the temperature-dependent magnetic parameters. Furthermore, the mechanism of magnetization reversal has been analyzed as a function of temperature by MOKE. The evolution of the magnetization curves can be satisfactory interpreted starting from the main achievements of the theoretical analysis of FMR data.
Malignant Pleural Mesothelioma (MPM) continues to be a challenging problem; because few patients may be treated with radical surgery and conventional chemotherapy have achieved very dismal results. ...Pemetrexed is a new drug with multitarget antifolate activity which seems to be particularly active in many solid tumors and also in MPM. The principal clinical experiences of pemetrexed alone or in combination with other compounds, chiefly platinum and its derivative, are reported. The Italian study on 1114 cases of MPM treated over 30 months is discussed and the definitive results will be available after a complete external review of all responsive patients.
We conducted a prospective randomized clinical trial to assess the mobilizing efficacy of filgrastim, lenograstim and molgramostim following a disease-specific chemotherapy regimen. Mobilization ...consisted of high-dose cyclophosphamide in 45 cases (44%), and cisplatin/ifosfamide/etoposide or vinblastine in 22 (21%), followed by randomization to either filgrastim or lenograstim or molgramostim at 5 microg/kg/day. One hundred and three patients were randomized, and 82 (79%) performed apheresis. Forty-four (43%) patients were chemonaive, whereas 59 (57%) were pretreated. A median number of one apheresis per patient (range, 1-3) was performed. The median number of CD34+ cells obtained after mobilization was 8.4 x 10(6)/kg in the filgrastim arm versus 5.8 x 10(6)/kg in the lenograstim arm versus 4.0 x 10(6)/kg in the molgramostim arm (P=0.1). A statistically significant difference was observed for the median number of days of growth factor administration in favor of lenograstim (12 days) versus filgrastim (13 days) and molgramostim (14 days) (P<0.0001) and for the subgroup of chemonaive patients (12 days) versus pretreated patients (14 days) (P<0.001). In conclusion, all three growth factors were efficacious in mobilizing peripheral blood progenitor cells with no statistically significant difference between CD34+ cell yield and the different regimens, and the time to apheresis is likely confounded by the different mobilization regimens.
Background: The aim of this study was to evaluate the effectiveness of granulocyte–macrophage colony-stimulating factor (GM-CSF) mouthwashes in the prevention of severe mucositis induced by high ...doses of chemotherapy. Patients and methods: Ninety consecutive patients affected by solid tumors and undergoing high-dose chemotherapy with autologous peripheral blood stem cell transplantation rescue were randomized to receive placebo versus GM-CSF mouthwash 150 µg/day. Patients were stratified on the basis of the conditioning treatment and the consequent different risk of severe oral mucositis. Treatment was administered from the day after the end of chemotherapy until the resolution of stomatitis and/or neutrophil recovery. Results: The statistical analyses were intention-to-treat and involved all patients who entered the study. The severity of stomatitis was evaluated daily by the physicians according to National Cancer Institute Common Toxicity Criteria. Both study and control groups were compared with respect to the frequency 30% versus 36%, χ2 exact test, not significant (NS) and mean duration (4.8 ± 4.7 versus 4.4 ± 2.7 days, t-test, NS) of severe stomatitis (grade ≥3). Oral pain was evaluated daily by patients themselves by means of a 10 cm analog visual scale: the mean (± standard error of the mean) maximum mucositis scores were 4.8 ± 3.5 versus 4.2 ± 3.5 cm (t-test, NS). Furthermore, 15/46 patients in the study group (33%) and 19/44 patients in the control group experienced pain requiring opioids (χ2 exact test, NS). Conclusion: We did not find any evidence to indicate that prophylaxis with GM-CSF mouthwash can help to reduce the severity of mucositis in the setting of the patients we studied.
Germ cell tumor is the most common malignancy in young men. The cure rate of these patients has tremendously increased in the cisplatin era, and recent results have indicated that the management of ...patients with GCT is still improving. The use of FDG-PET in the management of patients with GCT has been recently investigated. This report attempts to comprehensively review new advances and delineate the potential applications of FDG-PET in GCT.
Lipoplatin™ is a liposome encapsulated form of cisplatin. Phase I studies on lipoplatin have demonstrated that the compound has an excellent toxicity profile. Therefore we performed a phase II trial ...in heavily pre-treated patients with advanced non-small-cell lung cancer (NSClC), performance status 0-2 in which the primary end-point was response rate and secondary endpoints were safety and overall survival.
Nineteen patients, average age 64 years old, with stage IV NSClC, were treated with lipoplatin 100 mg/m
2
every two weeks, as second line chemotherapy.
We observed 1 partial remission (5.2%) and 3 stable diseases (15.9%). time to progression (ttp) was 16 weeks and median overall survival (OS) was 31 weeks (7.2 months). We observed G1-G2 toxicity during chemotherapy, mainly gastrointestinal with nausea and vomiting (4 patients), asthenia (3 patients), mucositis (2 patients) and anemia (4 patients).
Our phase II study does not support a more extensive use of lipoplatin in phase III studies. An increase of dosage and a better selection of patients are mandatory to un-derstand the real therapeutic activity of lipoplatin.
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