A new Rayleigh-like wave in guided propagation of antiplane waves in couple stress materials.

Motivated by the unexpected appearance of shear horizontal Rayleigh surface waves, we investigate the mechanics of antiplane wave reflection and propagation in couple stress (CS) elastic materials. Surface waves arise by mode conversion at a free surface, whereby bulk travelling waves trigger inhomogeneous modes. Indeed, Rayleigh waves are perturbations of the travelling mode and stem from its reflection at grazing incidence. As is well known, they correspond to the real zeros of the Rayleigh function. Interestingly, we show that the same generating mechanism sustains a new inhomogeneous wave, corresponding to a purely imaginary zero of the Rayleigh function. This wave emerges from 'reflection' of a bulk standing mode: This produces a new type of Rayleigh-like wave that travels away from, as opposed to along, the free surface, with a speed lower than that of bulk shear waves. Besides, a third complex zero of the Rayleigh function may exist, which represents waves attenuating/exploding both along and away from the surface. Since none of these zeros correspond to leaky waves, a new classification of the Rayleigh zeros is proposed. Furthermore, we extend to CS elasticity Mindlin's boundary conditions, by which partial waves are identified, whose interference lends Rayleigh-Lamb guided waves. Finally, asymptotic analysis in the thin-plate limit provides equivalent one-dimensional models.

Toroidal insulating inhomogeneity in an infinite space and related problems.

An analytic solution for the steady-state temperature distribution in an infinite conductive medium containing an insulated toroidal inhomogeneity and subjected to remotely applied uniform heat flux is obtained. The temperature flux on the torus surface is then determined as a function of torus parameters. This result is used to calculate the resistivity contribution tensor for the toroidal inhomogeneity required to evaluate the effective conductive properties of a material containing multiple inhomogeneities of this shape.

Evaluation of brain apoptosis in a CADASIL postmortem case.

OBJECTIVE: To evaluate the role of apoptosis in the pathogenesis of brain lesions in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary microangiopathy leading to cognitive decline and dementia, caused by mutations in the NOTCH3 gene. MATERIALS AND METHODS: Detection of apoptotic nuclei in temporal lobe, brain stem, medulla oblongata, hippocampus and basal ganglia from one young CADASIL patient was performed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL). RESULTS: Our results showed a great involvement of glial cells in apoptotic cell death in the majority of the brain regions examined; neuronal apoptosis was significantly present only in the brain stem region. CONCLUSIONS: We hypothesized that in the early stages of the disease neuronal involvement of apoptosis is limited to the cells of the brain stem, sparing the cortical area which is involved in neuronal apoptosis and cognitive decline later.

CSF levels of beta-amyloid 1-42, tau and phosphorylated tau protein in CADASIL.

BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be considered a useful model of pure subcortical vascular dementia (SVD) because it occurs in young adults, unlikely to have concomitant age- and Alzheimer's disease (AD)-related pathology. In patients with CADASIL we evaluated the cerebrospinal fluid (CSF) levels of beta-amyloid 1-42 (Abeta42), total tau protein (t-tau) and phosphorylated tau protein (p-tau), which are well-accepted biomarkers of AD. METHODS: The CSF Abeta42, t-tau and p-tau levels were determined with Innotest beta-amyloid 1-42, Innotest hTAU-Ag and Innotest Phospho-tau 181p sandwich enzyme-linked immunoassay, in 10 CADASIL patients and 17 healthy age-matched subjects. A case-control statistical analysis was carried out. RESULTS: CSF Abeta42 levels were significantly lower in CADASIL patients than in controls, whereas CSF t-tau and p-tau levels did not differ between the two groups. CONCLUSIONS: The pattern found in CADASIL patients is similar to that reported in those with sporadic SVD, suggesting that decreased CSF Abeta42 might be related to the subcortical vascular lesions in the white matter.

Human fibroblasts undergo oxidative stress-induced apoptosis without internucleosomal DNA fragmentation.

In order to evaluate the reliability of fibroblasts as a cell model for studying apoptosis, we tested the response of normal human fibroblasts to the oxidative stress inducers H(2)O(2) and 2-deoxy-D-ribose (dRib). Our results showed that fibroblasts treated with dRib and H(2)O(2) are induced to undergo apoptosis as demonstrated by reduction in total cell number, chromatin condensation, phosphatidylserine (PS) exposure, activation of caspase-3 and 7, changes in mitochondrial membrane potential and increase in the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive nuclei. However we only found a slight increase in the percentage of cells in the sub-G1 region evaluated by flow cytometry, and we did not observe DNA fragmentation by agarose gel electrophoresis. Early in apoptosis, DNA cleavage generates high molecular weight (HMW) fragments which can be detected by TUNEL assay; successively followed by a pronounced DNA brake down into low molecular weight (LMW) fragments, detected as a "DNA ladder" by conventional agarose gel electrophoresis and as an hypodiploid peak by propidium iodide (PI) flow cytometry assay. Our results thus suggest that only HMW fragmentation occurs in fibroblasts exposed to dRib or H(2)O(2) and the lack of internucleosomal DNA fragmentation may depend on the peculiar characteristics of human fibroblasts themselves, irrespective of the apoptotic stimulus used. The existence of distinct events leading to cell death in different cell types makes it necessary to use a combination of strategies and techniques to evaluate the occurrence of apoptosis.

[Pharmaceutic development of injectable Arduan]. / Az Arduan injekció gyógyszer-technológiája.

As a consequence of the presence of two ester groups in its molecule the main decomposition route of pipecuronium bromide (active ingredient of Arduan injection) is hydrolysis. In addition to this, autoxidation can also take place. In order to obtain a stable dosage form liophylized ampoules containing mannitol were prepared. Mannitol is not only a filling material but its role is also to decrease the dielectric constant of the solvent water thus increasing the stability of the drug substance before and during the liophylization procedure and after the dissolution of the content of the ampoules for administration. In order to protect the drug molecule against oxidation inert gas atmosphere was used during the production of the ampoules. The preparation is compatible with basic infusion solutions.

[Surgical prosthetic approach to sequelae of a case of noma involving half the face]. / Approche chirurgico-prothétique des séquelles d'un cas de noma intéressant l'hémi-face.

In this study, the authors discuss a prosthetic rehabilitation case resulting from loss of substance due to Noma. The dental prosthesis is made from tinted acrylic resin with a combination of two means of retention. The lower mean of retention is composed of a hook leaning on a handle which has been attached to that end on a metal armature and the upper mean of retention is connected to the bridge of spectacles.