Biomedical subjects

M Reinwald

Publications and source records attributed to M Reinwald.

6 recordsLinked to original sources

PubMed2006

Dephasing in (Ga,Mn)As nanowires and rings.

To understand quantum mechanical transport in a ferromagnetic semiconductor, the knowledge of basic material properties such as the phase coherence length and corresponding dephasing mechanism are indispensable ingredients. The lack of observable quantum phenomena has prevented experimental access to these quantities so far. Here we report the observations of universal conductance fluctuations in ferromagnetic (Ga,Mn)As. The analysis of the length and temperature dependence of the fluctuations reveals a T(-1) dependence of the dephasing time.

Journal Article↗

PubMed2006

Low-dose liposomal amphotericin B in the prevention of invasive fungal infections in patients with prolonged neutropenia: results from a randomized, single-center trial.

BACKGROUND: We performed a prospective, randomized, open-label trial to evaluate the efficacy of low-dose liposomal amphotericin B (L-AmB) to reduce the incidence of invasive fungal infections (IFI) in patients with hematological malignancies and prolonged neutropenia (>10 days) following intensive chemotherapy. PATIENTS AND METHODS: In 219 neutropenic episodes (NE) of 132 patients randomization was performed. Patients received either 50 mg L-AmB every other day (arm A) or no systemic antifungal prophylaxis (arm B). RESULTS: In the first NE of each patient the incidence of proven or probable IFI (primary end point) was five of 75 patients (6.7%) in arm A and 20 of 57 patients (35%) in arm B (P=0.001). Invasive aspergillosis occurred less frequently in patients receiving L-AmB-prophylaxis (P=0.0057), whereas the reduction of invasive candidiasis did not reach statistical significance (P=0.0655). In all NE the incidence of IFI was five of 110 NE (4.6%) in arm A versus 22 of 109 NE (20.2%) in arm B (P<0.01). Adverse events, possibly related to L-AmB, were observed in five NE (4.6%) and L-AmB was discontinued in three NE (2.8%). No grade 3 or 4 toxicities were observed. CONCLUSIONS: Antifungal prophylaxis with low-dose L-AmB proved to be feasible and effective in our trial.

Adult↗

PubMed2006

Probing a Kondo-correlated quantum dot with spin spectroscopy.

We investigate the Kondo effect and spin blockade observed in a many-electron quantum dot and study the magnetic field dependence. At lower fields, a pronounced Kondo effect is found, which is replaced by the spin blockade at higher fields. In an intermediate regime, both effects are visible. We make use of this combined effect to gain information about the internal spin configuration of our quantum dot. We find that the data cannot be explained assuming regular filling of electronic orbitals. Instead, spin polarized filling seems to be probable.

Journal Article↗

PubMed2004

Spatially resolved manipulation of single electrons in quantum dots using a scanned probe.

The scanning metallic tip of a scanning force microscope was coupled capacitively to electrons confined in a lithographically defined gate-tunable quantum dot at a temperature of 300 mK. Single electrons were made to hop on or off the dot by moving the tip or by changing the tip bias voltage owing to the Coulomb-blockade effect. Spatial images of conductance resonances map the interaction potential between the tip and individual electronic quantum dot states. Under certain conditions this interaction is found to contain a tip-voltage induced and a tip-voltage-independent contribution.

Journal Article↗

PubMed2004

Spontaneous supercurrent induced by ferromagnetic pi junctions.

We present magnetization measurements of mesoscopic superconducting niobium loops containing a ferromagnetic (PdNi) pi junction. The loops are prepared on top of the active area of a micro-Hall sensor based on high mobility GaAs/AlGaAs heterostructures. We observe asymmetric switching of the loop between different magnetization states when reversing the sweep direction of the magnetic field. This provides evidence for a spontaneous current induced by the intrinsic phase shift of the pi junction. In addition, the presence of the spontaneous current near zero applied field is directly revealed by an increase of the magnetic moment with decreasing temperature, which results in half integer flux quantization in the loop at low temperatures.

Journal Article↗

PubMed2002

Quantitative real-time RT-PCR detects elevated Wilms tumor gene (WT1) expression in autologous blood stem cell preparations (PBSCs) from acute myeloid leukemia (AML) patients indicating contamination with leukemic blasts.

High-dose chemotherapy with subsequent autologous stem cell transplantation is believed to be of therapeutic benefit in patients with acute myeloid leukemia (AML), especially when no allogeneic bone marrow donor is available. One of the main risks is contamination of the stem cell preparations with leukemic blasts, which may account for a higher relapse rate compared to allogeneic bone marrow transplantation. Since overexpression of WT1 is common in leukemic blasts, we investigated, whether PBSCs from AML patients express WT1 at a higher level as compared to patients with solid cancers. PBSCs of seven patients with AML and of five patients with solid cancers were investigated for WT1 expression. Total WT1 copy count was determined in a standardized quantitative real time RT-PCR. WT1 expression was found in all AML PBSCs with an average copy number of 49.99 +/- 61.09. In solid cancers WT1 expression was statistically significantly lower with a copy number of 3.51 +/- 1.92. In AML patients with sustained complete remission we found a nearly significantly lower WT1 expression than in patients who relapsed within the first year after stem cell transplantation. Our data show a higher WT1 expression in PBSCs of AML patients compared to patients with solid cancers. This finding might indicate a contamination with leukemic blasts. Quantification of WT1 in PBSCs might therefore be useful to estimate the risk of relapse after autologous stem cell transplantation in AML patients.

Acute Disease↗