Quasiperiodic Tip Splitting in Directional Solidification

We report experimental results on the tip splitting dynamics of seaweed growth in directional solidification of succinonitrile alloys with poly(ethylene oxide) or acetone as solutes. The seaweed or dense branching morphology was selected by solidifying grains which are oriented close to the {111} plane. Despite the random appearance of the growth, a quasiperiodic tip splitting morphology was observed in which the tip alternately splits to the left and to the right. The tip splitting frequency f was found to be related to the growth velocity V as a power law f V^{1.5}. This finding is consistent with the predictions of a tip splitting model that is also presented. Small anisotropies are shown to lead to different kinds of seaweed morphologies.Comment: 4 pages, 7 figures, submitted to Physical Review Letter

Very high rotational frequencies and band termination in 73Br

Rotational bands in 73Br have been investigated up to spins of 65/2 using the EUROBALL III spectrometer. One of the negative-parity bands displays the highest rotational frequency 1.85 MeV reported to date in nuclei with mass number greater than 25. At high frequencies, the experimental dynamic moment of inertia for all bands decrease to very low values, indicating a loss of collectivity. The bands are described in the configuration-dependent cranked Nilsson-Strutinsky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination case in the A = 70 mass region.Comment: 6 pages, 6 figures, submitted to Phys. Rev. C as a Rapid Communicatio

Psychiatric and neurocognitive consequences of endogenous hypercortisolism

Psychiatric and neurocognitive symptoms due to hypercortisolism were already described by Harvey Cushing in his original paper on patients with Cushing's syndrome (CS). Nowadays, it is well known that psychiatric and cognitive complaints are two of the most common, and most distressing, symptoms in patients with CS. Psychiatric symptoms are indeed a major clinical manifestation of CS. The most commonly observed psychiatric conditions are depression and anxiety, whilst mania and psychosis are less common. Several domains of cognitive function are impaired at diagnosis, including episodic and working memory, executive function and attention. Following treatment, one-fourth of the patients still experience depressed mood, and the cognitive impairments are only partially restored. Consequently, quality of life in patients with CS is severely and persistently affected. Neuroimaging studies have also illustrated the deleterious effects of hypercortisolism on the brain by demonstrating reduced grey matter volumes and cortical thickness, altered resting-state functional responses and during cognitive tasks, as well as widespread reduced white matter integrity, especially in structures important for cognitive function and emotional processing, both before and after successful abrogation of hypercortisolism. In this paper, we summarize the current knowledge on the psychiatric and neurocognitive consequences of hypercortisolism in patients with CS, both before, and after successful treatment. In addition, we review the structural and functional brain abnormalities associated with hypercortisolism and discuss the influence of these factors on quality of life

Closed shells at drip-line nuclei

The shell structure of magic nuclei far from stability is discussed in terms of the self-consistent spherical Hartree-Fock-Bogoliubov theory. In particular, the sensitivity of the shell-gap sizes and the two-neutron separation energies to the choice of particle-hole and particle-particle components of the effective interaction is investigated.Comment: 19 pages, LaTeX, 8 uuencoded figures available upon reques

Intracellular Fas ligand in normal and malignant breast epithelium does not induce apoptosis in Fas-sensitive cells

Fas ligand (FasL) is expressed on some cancers and may play a role in the immune evasion of the tumour. We used immuno-histochemistry to study the expression of Fas and FasL in tissue samples from breast cancer patients, as well as normal breast tissue. Our results show that Fas and FasL are co-expressed both in normal tissue and in breast tumours. Fas and FasL mRNA were expressed in fresh normal and malignant breast tissue, as well as cultured breast epithelium and breast cancer cell lines. Flow cytometry analysis of live cells failed to detect FasL on the surface of normal or malignant breast cells; however, both stained positive for FasL after permeabilization. Fas was detected on the surface of normal breast cells and T47D and MCF-10A cell lines but only intracellularly in other breast cell lines tested. Neither normal breast epithelium nor breast cell lines induced Fas-dependent apoptosis in Jurkat cells. Finally, 20 tumour samples were stained for apoptosis. Few apoptotic cells were detected and there was no increase in apoptotic cells on the borders between tumour cells and lymphocytes. We conclude that FasL is expressed intracellularly in both normal and malignant breast epithelium and unlikely to be important for the immune evasion of breast tumours. © 2000 Cancer Research Campaign http://www.bjcancer.co