Electromagnetic cloaking in convex and concave media with surface modelled as a parameterised function.

The onset of transformation optics has opened avenues for designing of a plenitude of applications related to propagation of electromagnetic waves in anisotropic media. In this paper, an algorithm is proposed using a coordinate transformation and a piecewise function for the purpose of designing a three dimensional cloak having an arbitrary geometry which could be convex or non-convex in nature. The surfaces of the cloak as well as of the body under consideration are assumed to be conformal to each other. For an arbitrary geometry, the coordinate system needed to model the surface can be a non-orthogonal system. For the purpose of verification of the algorithm, a ray tracing process is carried out for an ellipsoid as well as for a concave surface having axial symmetry. In order to solve the Hamiltonian equation for the purpose of ray tracing, the process of finding the derivatives analytically, for an arbitrary geometry as considered here, becomes very cumbersome. Here, a numerical method is described which provides a better approximation to the partial derivatives than the conventional finite difference approach based on forward differences.

Narrowing in on the causative defect of an intriguing X-linked myopathy with excessive autophagy.

BACKGROUND: X-Linked myopathy with excessive autophagy (XMEA) is a childhood-onset slowly progressive disease of skeletal muscle with no cardiac, nervous system, or other organ involvement. Pathology is distinctive: membrane-bound autophagic vacuoles, multifold reduplication of the basement membrane, and intense deposition of membrane attack complex and calcium at the myofiber surface. XMEA has been linked to the most telomeric 10.5 cM of Xq28. The authors now report identification of new families, refinement of the locus, mapping of genes to the region, and screening of candidate genes for mutations. METHODS AND RESULTS: Seven new families were ascertained, including an American family with XMEA. Using 11 new microsatellite genetic markers, the authors fine-mapped a recombination in this family and a common ancestral haplotype in two French families, which localized the gene in a 4.37-Mb region. Sequence data were assembled from public and private databases and a near-continuous sequence derived for the entire region. With this sequence, a gene map of 82 genes and 28 expressed sequence tag clusters was constructed; to date, 12 candidate genes have been screened for mutations. CONCLUSIONS: This study doubles the number of reported families with XMEA and more firmly establishes its distinctive clinicopathologic features. It also advances the search for the XMEA causative defect by reducing the disease locus to approximately half its previous size, assembling an almost complete sequence of the refined region, identifying all known genes in this sequence, and excluding the presence of mutations in 10% of these genes.

Cerebrovascular diseases in west central India. A report on angiographic findings from a prospective study.

Cerebral angiographic findings in ischaemic stroke are described and discussed in detail. Though the Indian patients studied had altogether different social customs, living standards, and dietary habits from Western people, the relative incidence of various cerebral vascular lesions did not differ significantly. Irrespective of the poor nutritional status of the patients, thrombosis associated with atherosclerosis was chiefly responsible for a non-embolic cerebral infarction. Atherothrombosis in the young normotensive persons not showing any evidence of arteritis, diabetes mellitus, or hypercholesterolaemia was also identified.The grave risks involved in cerebral angiography in cases of acute stroke are re-emphasized.As to prognosis, the nutritional status, the type and territory of an ictal lesion, and the blood levels of sugar and cholesterol had no significant influence on the immediate survival-after a non-embolic cerebral infarction. However, a significantly greater number of deaths were encountered in the hypertensive patients. Female patients and patients with a large cerebral infarction had a poor prognosis.