Metallic state in cubic FeGe beyond its quantum phase transition

We report on results of electrical resistivity and structural investigations on the cubic modification of FeGe under high pressure. The long-wavelength helical order (T(C) = 280 K) is suppressed at a critical pressure p(c) approximately 19 GPa. An anomaly at T(X)(p) and strong deviations from a Fermi-liquid behavior in a wide pressure range above p(c) suggest that the suppression of T(C) disagrees with the standard notion of a quantum critical phase transition. The metallic ground state persisting at high pressure can be described by band-structure calculations if zero-point motion is included. The shortest FeGe interatomic distance display discontinuous changes in the pressure dependence close to the T(C)(p) phase line.

Die neurologische Untersuchung – eine bleibende Kunst?

Die neurologische Untersuchung ist eine Herausforderung an den Arzt wie an den Patienten. Das Ziel ist die Erfassung eines Syndroms – und nicht die Diagnose – mit den Werkzeugen der Anamnese und Befunderhebung. Diese werden in groben Zügen, gewichtet, plakativ und gelegentlich provokativ dargestellt.

Crystal structures of (barium, europium) platinum trigermanium, Ba1-xEuxPtGe3 (x = 0, 0.27, 1)

BaGe3Pt, tetragonal, I4mm (no. 107), a = 4.5636(2) Å, c = 10.2341(6) Å, V = 213.1 Å3, Z = 2, Rgt(F) = 0.030, wRref(F2) = 0.074, T = 293 K.

Ba0.73Eu0.27Ge3Pt, tetragonal, I4mm (no. 107), a = 4.5432(1) Å, c = 10.1763(2) Å, V = 210.0 Å3, Z = 2, Rgt(F) = 0.025, wRref(F2) = 0.061, T = 293 K.

EuGe3Pt, tetragonal, I4mm (no. 107), a = 4.4633(1) Å, c = 10.0625(4) Å, V = 200.5 Å3, Z = 2, Rgt(F) = 0.018, wRref(F2) = 0.035, T = 293 K.

How depth of anesthesia influences the blood oxygenation level-dependent signal from the visual cortex of children

BACKGROUND AND PURPOSE

Functional MR imaging (fMRI) is playing an important role in investigations of cortical development and maturation. Functional MR imaging in young children or infants frequently involves measuring a clinical population under sedation or anesthesia. We examined the effect of depth of anesthesia on the extent and amplitude of the blood oxygen level-dependent (BOLD) response.

METHOD

We performed BOLD-based fMRI on a visual stimulus flickering at 8 Hz at sevoflurane concentrations of 0.5 minimum alveolar concentration (MAC), 0.75 MAC, and 1.0 MAC, on 16 children at least 5 years of age. We determined the extent of activation by counting the number of activated voxels and assessed the change in the local deoxyhemoglobin concentration by comparing DeltaR2*.

RESULTS

The number of activated voxels of the positive BOLD response was higher at 0.75 MAC than at 0.5 MAC or 1.0 MAC. The magnitude of their mean DeltaR2* steadily declined as the level of sevoflurane was increased from 0.5 MAC to 1.0 MAC. The extent of activation of the negative BOLD response declined progressively from 0.5 MAC to 1.0 MAC. The magnitude of their mean amplitude of the DeltaR2* did not change with sevoflurane concentrations. The change in the extent of activation and the magnitude of DeltaR2* when the concentration of sevoflurane increased from 0.5 MAC to 0.75 MAC was due to its vasodilative property. The change in the extent of activation and the amplitude of DeltaR2* following the increase in the concentration of sevoflurane from 0.75 MAC and 1.0 MAC was due to its anesthetic property. This was the case for both the positive and negative BOLD response.

CONCLUSIONS

Careful adjustment of anesthetic depth can be used advantageously when performing BOLD-based fMRI measurements in children.

Retinoic acid induced myelomeningocele in fetal rats: characterization by histopathological analysis and magnetic resonance imaging

The prevention of human neural tube defects by folic acid administration and the potential for fetal surgical intervention for myelomeningocele (MMC) have renewed interest in the molecular pathways and pathophysiology of spina bifida. Animal models for assessment of the early developmental biology and pathophysiology of this lesion are needed. The goal of this study was to develop and characterize a non-surgical rat model of MMC. Time-dated Sprague-Dawley rats were gavage fed different doses of retinoic acid (RA) dissolved in olive oil at E10 (maternal n = 55, fetal n = 505). Control animals received olive oil alone (maternal n = 20, fetal n = 265) or were untreated (maternal n = 5, fetal n = 63). Fetuses were analyzed by detailed histopathology and MRI. Overall, isolated MMC occurred in 60.7% (307/505) of RA-exposed fetuses and no controls. Histopathology confirmed the entire spectrum of severity observed in human MMC, ranging from exposure of the cord with intact neural elements to complete cord destruction. MRI of the brain of MMC fetuses confirmed structural changes similar to humans with Arnold-Chiari malformation, including downward displacement of the cerebellum to just above the foramen magnum and compression of the developing medulla into a small posterior fossa. In conclusion, the RA-induced rat model of MMC is developmentally and anatomically analogous to human MMC. This relatively efficient and cost-effective model of MMC should facilitate investigation of the developmental biology and pathophysiology of MMC, and may be useful for the evaluation of further strategies for prenatal treatment.

[Recurrent strongyloidiasis as an indicator of HTLV-1 infection]

HISTORY AND CLINICAL FINDINGS

A 53-year-old West African man presented two years after a travel to Guinea because of severe headache, neck stiffnes, fever and pruritus. The patient had been in orthopedical treatment for the last five months.

INVESTIGATIONS

Stool microscopy revealed a high number of Strongyloides stercoralis larvae. Hematology, biochemistry and all other parasitology results were normal. HIV-1/2 testing was negative and CD4+-lymphocyte count was normal. Concomitant infection by Human T Cell lymphotropic virus type 1 (HTLV-1) was confirmed by serology and PCR. The phylogenetic analysis confirmed African origin of the virus.

TREATMENT

The infection responded to a five-day course of albendazol at 400 mg/d but during the following five years repeat recrudescences were observed inspite of high-dosage and prolonged antiparasitic treatments. Eventually, eradication of the infection was achieved by a four day course of ivermectin 0.2 mg/kg/d.

CONCLUSIONS

Although both strongyloidiasis and HTLV-1 infections occur most frequently in tropical areas, these may also be observed in temperate regions. Suppression of the immune system by HTLV-1 differs from that by HIV. CD4+-lymphocytes were rarely decreased. Prolonged treatment with ivermectin in a dosage exceeding the current recommendations may be required in HTLV-1 infected patients and was well tolerated. The unusual presentation of the infection with muscular symptoms contributed to the delay of the diagnosis. HTLV-1 positive patients must be monitored for years. They and their partners must be instructed how to prevent transmission of the virus.

Gesundheit in der Mediengesellschaft

The article sketches concepts of entertaining health education programmes on television as discussed in the new sub-discipline of health communication in Germany and describes some examples and aspects of cooperation between the Federal Center for Health Education (BZgA/FCHE) Cologne as an institutional health education agency and German television partners. Specific chances and problems of entertaining forms of mass media health education on television are discussed. Finally, perspectives for institutional health education in relation to television are discussed.

Langzeit-Entwicklung von Dissektionen der A. carotis interna: Quantitative Blutvolumenfluss-Untersuchungen mit der 2D cine Phasen-Kontrast MR Technik

PURPOSE

To use the magnetic resonance (MR) phase-contrast technique as a non-invasive method to determine blood volume flow in internal carotid artery (ICA) dissection, which has variable initial volume flow reduction and long term hemodynamic compromise. ICA dissection can lead to partial or complete recanalization or persistent occlusion, and strong clinical motivation exists for reliable assessment of the blood flow, in particular blood volume flow, in the carotid artery circulation after ICA dissection.

MATERIALS AND METHODS

Blood volume flow in the carotid artery circulation was quantified in 28 patients with unilateral ICA dissection and 20 age-matched normal controls. Blood volume flow was measured in the ICAs and the common carotid arteries (CCAs) using 2D cine phase-contrast MR imaging. Final measurements were performed until after at least 6 months the hemodynamic compromise showed no changes by ultrasound and MRA.

RESULTS

In long term follow up, 11/28 patients demonstrated remaining vessel occlusion, 10/28 partial and 7/28 complete recanalizations. Patients with ICA occlusion showed a significant contralateral volume flow increase (mean 56 %, p < 0.001) in comparison to normal controls. Patients with partial recanalization demonstrated volume flow rates between 24 ml/min and 188 ml/min in the dissected ICA and a less but significant (p < 0.001) increase in the contralateral volume flow. In patients with complete recanalization, normal volume flow conditions were found for both ICAs and CCAs.

CONCLUSION

In ICA dissection, quantitative volume flow determination using 2D cine phase-contrast MR imaging is helpful in the initial assessment and long term follow-up of hemodynamic compromise. ICA dissection demonstrated a partial or complete recanalization in nearly (2/3) of the investigated patients and a persisting vessel occlusion in little more than (1/3). Compensatory contralateral increase in volume flow was found.

Refinement of the crystal structure of Bi-II, at 2.54 GPa

Bi, monoclinic, C12/m1 (No. 12), a = 6.67256(1) Å, b = 6.1108(2) Å, c = 3.30013(9) Å, β = 110.412(2)°, V = 126.1 Å3, Z = 4, R(P) = 0.118, R(I) = 0.087, T = 295 K, P = 2.54 GPa.

Chemical composition of the attachment pad secretion of the locust Locusta migratoria

This study is the first attempt to characterise the chemical composition of the secretion of the smooth pads of the locust Locusta migratoria and to relate this to the composition of the cuticle coverage of the pads and the wings. Gas-chromatography and mass-spectrometry (GC-MS) were the principal techniques used for the characterization of these materials. Secretion droplets were visualised and quantified with the aid of diverse microscopic techniques. The chemical composition of prints is shown to differ from the cuticle coverage, in particular, with respect to the fatty acid distribution: in the secretion, saturated and unsaturated fatty acids with chain lengths between C(16) and C(20) in both the free form and as glycerides predominate, whereas cuticle coverage contains waxes of long-chained fatty-acids bound to long-chain primary alcohols. The second important difference is the significant amount of glucose and other saccharides found in methanolyzates of the pad fluid. A considerable amount of the amino acids (up to 53%) was detected in the non-volatile portion of the fluid. Data obtained from the shock-freezing, carbon-platinum coating and replica preparation show that the secretory droplets contain nano-droplets on their surfaces. The results lead us to suggest that the pad secretion is an emulsion consisting of lipidic nano-droplets dispersed in an aqueous liquid. According to the chemical composition of the secretion, a high-viscosity of the fluid may be suggested. Presumably, the fluid is a kind of a coupling agent, promoting and strengthening adhesion between otherwise incompatible materials by providing the proximity of contact for intermolecular forces.