Giant spin splitting in optically active ZnMnTe/ZnMgTe core/shell nanowires.

An enhancement of the Zeeman splitting as a result of the incorporation of paramagnetic Mn ions in ZnMnTe/ZnMgTe core/shell nanowires is reported. The studied structures are grown by gold-catalyst assisted molecular beam epitaxy. The near band edge emission of these structures, conspicuously absent in the case of uncoated ZnMnTe nanowires, is activated by the presence of ZnMgTe coating. Giant Zeeman splitting of this emission is studied in ensembles of nanowires with various average Mn concentrations of the order of a few percent, as well as in individual nanowires. Thus, we show convincingly that a strong spin sp-d coupling is indeed present in these structures.

[Magnetic resonance spectroscopy (HMRS) in migraine]. / Badanie spektroskopii rezonansu magnetycznego (HMRS) w migrenie.

INTRODUCTION: There are 4 million people suffering from migraine in Poland, which account; for 10% of national population. Pathomechanism of migraine is not fully understood. In the recent years multiple studies in migraine patients revealed occurrence of metabolic disorders in nervous system tissue. MATERIAL AND METHODS: In 30 subjects with migraine diagnosis magnetic resonance spectroscopy examination was performed. Relative concentration ratio (WSS) of metabolites level to creatinine (Cr) level was measured. The obtained values were compared to findings in control groups. RESULTS: Linear correlation between increase in both WSS Lac/Cr value in left temporal lobe and WSS ml/Cr value in right frontal lobe and a number of migraine attacks per year in migraine patients was observed. It also turned out that WSS ml/Cr vox3 value depends on a total number of migraine attacks in life. A lactic acid level in left temporal lobe normalizes along with the elongation of interattack interval. There is a statistically significant difference of WSS ml/Cr value measured in left temporal lobe and right frontal lobe between migraine patients and control group. There is a statistically significant difference of WSS Cho/Cr value measured in left temporal lobe and right frontal lobe between migraine subjects and control groups.

The impact of postadmission glycemia on stroke outcome: Glucose normalisation is associated with better survival.

BACKGROUND: Hyperglycemia on admission increases the risk of death in patients with acute stroke. It remains unclear whether glucose normalisation after admission is associated with improved survival. The goal of the study was to determine the relationship between postadmission glucose levels and mortality in stroke patients with and without admission hyperglycemia. METHODS: 302 patients with first-ever ischemic stroke and without prior diagnosis of diabetes mellitus were enrolled. Random plasma glucose level was measured on admission and fasting glucose on day 1, 2, 3, 5 and 7. Hyperglycemia on admission was defined as glucose level > or = 7.8 mmol/L. Postadmission hyperglycemia was diagnosed if mean postadmission fasting glucose level was > or = 6.1 mmol/L. RESULTS: After multivariable adjustment, postadmission hyperglycemia was associated with higher risk of death regardless of admission glucose levels (HR: 1.80, 95%CI: 1.39-2.86, P<0.01). Postadmission hyperglycemia increases risk of death in both patients with admission hyperglycemia (HR: 4.83, 95%CI: 1.93-12.06, P<0.01) and those with admission normoglycemia (HR: 1.64, 95%CI: 1.06-2.54, P=0.03). In patients with admission hyperglycemia glucose normalisation after admission was associated with reduced risk of death compared to those with persistent hyperglycemia (HR: 0.21, 95%CI: 0.08-0.52). The patients who were normoglycemic on day 1 and developed hyperglycemia on next days had increased risk of death compared to persistent normoglycemic patients (HR: 1.55, 95%CI: 1.01-2.39, P=0.04). CONCLUSIONS: Postadmission, but not admission, hyperglycemia is associated with increased risk of death. Glucose normalisation after admission is associated with better survival.

Zn(1-x)MnxTe diluted magnetic semiconductor nanowires grown by molecular beam epitaxy.

It is shown that the growth of II-VI diluted magnetic semiconductor nanowires is possible by the catalytically enhanced molecular beam epitaxy (MBE). Zn(1-x)MnxTe NWs with manganese content up to x=0.60 were produced by this method. X-ray diffraction, Raman spectroscopy, and temperature dependent photoluminescence measurements confirm the incorporation of Mn(2+) ions in the cation substitutional sites of the ZnTe matrix of the NWs.

GaAs:Mn nanowires grown by molecular beam epitaxy of (Ga,Mn)as at MnAs segregation conditions.

GaAs:Mn nanowires were obtained on GaAs(001) and GaAs(111)B substrates by molecular beam epitaxial growth of (Ga,Mn)As at conditions leading to MnAs phase separation. Their density is proportional to the density of catalyzing MnAs nanoislands, which can be controlled by the Mn flux and/or the substrate temperature. After deposition corresponding to a 200 nm thick (Ga,Mn)As layer the nanowires are around 700 nm long. Their shapes are tapered, with typical diameters around 30 nm at the base and 7 nm at the tip. The wires grow along the 111 direction, i.e., along the surface normal on GaAs(111)B and inclined on GaAs(001). In the latter case they tend to form branches. Being rooted in the ferromagnetic semiconductor (Ga,Mn)As, the nanowires combine one-dimensional properties with the magnetic properties of (Ga,Mn)As and provide natural, self-assembled structures for nanospintronics.

Nonvolatile gate effect in a ferroelectric-semiconductor quantum well.

Field effect transistors with ferroelectric gates would make ideal rewritable nonvolatile memories were it not for the severe problems in integrating the ferroelectric oxide directly on the semiconductor channel. We propose a powerful way to avoid these problems using a gate material that is ferroelectric and semiconducting simultaneously. First, ferroelectricity in semiconductor (Cd,Zn)Te films is proven and studied using modified piezoforce scanning probe microscopy. Then, a rewritable field effect device is demonstrated by local poling of the (Cd,Zn)Te layer of a (Cd,Zn)Te/CdTe quantum well, provoking a reversible, nonvolatile change in the resistance of the 2D electron gas. The results point to a potential new family of nanoscale one-transistor memories.

[Side effects, unwanted drug interactions and the problem of cardiotoxicity]. / Dzialania niepozadane i niekorzystne interakcje leków a problem kardiotoksycznosci.

The problem of drug interactions is very important in pharmacotherapy. The interactions of some drugs (antihistamines, macrolides, fluoroquinolones, cisapride) with other can induce ventricular arrhythmias. A lot of non-antiarrhytmic drugs can prolong the QT interval, induce torsade de pointes and cardiotoxicity.