Observation of a roton collective mode in a two-dimensional Fermi liquid.

Understanding the dynamics of correlated many-body quantum systems is a challenge for modern physics. Owing to the simplicity of their Hamiltonians, (4)He (bosons) and (3)He (fermions) have served as model systems for strongly interacting quantum fluids, with substantial efforts devoted to their understanding. An important milestone was the direct observation of the collective phonon-roton mode in liquid (4)He by neutron scattering, verifying Landau's prediction and his fruitful concept of elementary excitations.

Observation of a superfluid component within solid helium.

We demonstrate by neutron scattering that a localized superfluid component exists at high pressures within solid helium in aerogel. Its existence is deduced from the observation of two sharp phonon-roton spectra which are clearly distinguishable from modes in bulk superfluid helium. These roton excitations exhibit different roton gap parameters than the roton observed in the bulk fluid at freezing pressure.

Morphology of thin nanocomposite films of asymmetric diblock copolymer and magnetite nanoparticles.

Thin self-assembled nanocomposite films of an asymmetric diblock copolymer and nanoparticles are fabricated. The morphologies of the films of the diblock copolymer poly(styrene-block-n-butyl methacrylate), P(Sd-b-BMA), with different volume fractions of large magnetite Fe(3)O(4) nanoparticles are studied before and after annealing. Neutron reflectometry reveals remarkable evidence that confining asymmetric copolymer to a limit of two layers forces the film, after the annealing, to form a mixed cylindrical-lamellar two-layer structure.

Membrane-induced folding and structure of membrane-bound annexin A1 N-terminal peptides: implications for annexin-induced membrane aggregation.

Annexins constitute a family of calcium-dependent membrane-binding proteins and can be classified into two groups, depending on the length of the N-terminal domain unique for each individual annexin. The N-terminal domain of annexin A1 can adopt an alpha-helical conformation and has been implicated in mediating the membrane aggregation behavior of this protein. Although the calcium-independent interaction of the annexin A1 N-terminal domain has been known for some time, there was no structural information about the membrane interaction of this secondary membrane-binding site of annexin A1.

[Advance refusal of treatment in case of loss of autonomy due to persistent brain disease].

A short overview is given of the current debate on ethics and legal clarification of the range and binding force of so-called living wills demanding interruption of treatment in case of loss of autonomy due to persistent or progressive brain disease. Using the examples of dementia and persistent vegetative states - conditions with growing significance for psychiatrists - the binding force of living wills is examined for cases in which the irreversibility and extent of consciousness loss cannot be predicted with certainty. The range of living wills' authority appears also unclear.

[Montelukast-free interval before inhalational bronchial allergen provocation].

Background: Leukotrienes are potent bronchoconstrictive and proinflammatory mediators in bronchial asthma. In a previous study on 16 subjects with bronchial asthma (two randomized groups) we showed that montelukast (10 mg daily) significantly suppressed allergen provocation with specific allergens (mites and pollen) (p = 0.0005).

Transverse and lateral structure of the spin-flop phase in fe/cr antiferromagnetic superlattices.

Direct evidence of the nonuniformly canted state of the spin-flop phase induced by a magnetic field applied to Fe/Cr(100) superlattices is obtained by polarized neutron reflectometry. It is unambiguously demonstrated that the magnetization of the alternating Fe layers is twisted through the multilayer stack proving a stable noncollinear configuration. The maximal tilt at the end layers progressively reduces towards the center of the multilayer.

[Influence of montelukast on inhalational bronchial allergen provocation].

Background: Leukotrienes are potent bronchoconstrictive and proinflammatory mediators in bronchial asthma. A randomized, cross-over study on 16 subjects assigned to two groups investigated whether premedication with the leukotriene antagonist montelukast (10 mg daily for 21 days) has a relevant effect on inhalational bronchial allergen provocation.

Method: Allergens were inhaled by atomizing commercial provocation solutions in dilutions of 1 : 1000, 1 : 100, 1 : 50, 1 : 10 and 1 : 5 with a nebulizer (Pari).

Coarsening of antiferromagnetic domains in multilayers: the key role of magnetocrystalline anisotropy.

The domain structure of an antiferromagnetic superlattice is studied. Synchrotron Mössbauer and polarized neutron reflectometric maps show micrometer-size primary domain formation as the external field decreases from saturation to remanence. A secondary domain state consisting mainly of at least 1 order of magnitude larger domains is created when a small field along the layer magnetizations induces a bulk-spin-flop transition.

Pre-eclampsia associated alterations of the elastic fibre system in umbilical cord vessels.

Although pre-eclampsia (PE) is often associated with fetal hypoxia, hypertension and/or disturbed function of the fetal circulation, the effect of these altered hemodynamic parameters on the structure and composition of umbilical vessels has not been systematically investigated before. Therefore, this study focuses on PE-associated changes of the elastic fibre system in umbilical cord vessels investigated by light and electron microscopy, immunocytochemistry and biochemistry. In umbilical cord veins, no changes in thickness of the vessel wall or of any sublayer were observed.

Variability of cerebral blood flow deficits in 99mTc-HMPAO SPECT in patients with Alzheimer's disease.

The purpose of this study was to analyse the frequency of the different pathological perfusion patterns in SPECT in a clinical, unselected population of patients with Alzheimer's disease. In 91 patients and 16 control subjects regional cerebral blood flow (rCBF) was measured with Single Photon Emission Computed Tomography (SPECT) using 99mTc-hexa-methyl-propyleneamine oxime (HMPAO). 95% confidence intervals obtained from the perfusion values of the control subjects were used to define normal perfusion ranges.

Apolipoprotein E type 4 allele and Alzheimer's disease: effect on age at onset and relative risk in different age groups.

The effect of the apolipoprotein E (apoE) genotype on the age at onset of Alzheimer's disease (AD) and the relative risk conferred by the apoE epsilon 4 allele were studied in 91 patients and 69 healthy age-matched controls. According to the age of presentation, which varied from 44 to 95 years, subjects were divided into four groups. The inheritance of at least one epsilon 4 allele was associated with a significant reduction of the age at onset by 7.

[The "neuroleptic threshold"--a review of the literature].

The neuroleptic threshold theory raised the expectation that schizophrenic patients could be treated with an optimal, individual neuroleptic dosage, causing no side effects. Although most existing studies do not fulfill current methodological standards, a few methodologically convincing analyses confirm that good clinical results can be achieved with relatively low dosages (4 mg haloperidol equivalent per day). Thus, the neuroleptic threshold theory and methods related to it deserve further research.

[Willingness to participate in dementia research by relatives of Alzheimer patients and family members of cognitively normal persons].

We investigated the willingness to participate in dementia research of relatives of demented (n = 52) and cognitively unimpaired elderly individuals (n = 42). This unrepresentative sample was given a questionnaire to determine the rate of approval with respect to two research examples, the first of which referred to a therapeutic study with potential individual benefits, the second to a diagnostic research project without such benefits. Independent of potential individual benefits, an overwhelming majority acknowledged the necessity for dementia research and consented to participate in the given research examples.

[The apolipoprotein E-epsilon 4 allele is a risk factor for Alzheimer disease with early and late onset].

The apolipoprotein E genotype was determined in 50 patients with clinically diagnosed and prospectively confirmed Alzheimer's disease of mild to moderate severity and in 50 healthy age- and sex-matched controls. The frequency of the epsilon 4 allele was increased in the patients irrespective of the age at onset and of a possible familial transmission of the disease. It was associated with a relative risk of 2.

[The new euthanasia-discussion from the psychiatric viewpoint].

The practice to kill terminally ill patients on their own demand has resulted in the Netherlands in a decriminalisation of active euthanasia which thus has fundamentally changed the way to deal with dying patients. Sooner or later this development will extend to other European countries as well as to the USA. Involuntary euthanasia of severely handicapped newborn children or of demented persons is propagated by the practical ethics of P.