Willis couplings in continuously varying cross-sectional area duct.

Acoustic wave propagation in a one-dimensional periodic and asymmetric duct is studied theoretically and numerically to derive the effective properties. Closed form expressions for these effective properties, including the asymmetric Willis coupling, are derived through truncation of the Peano-Baker series expansion of the matricant (which links the state vectors at the two sides of the unit-cell) and Padé's approximation of the matrix exponential. The results of the first-order and second-order homogenization (with Willis coupling) procedures are compared with the numerical results. The second-order homogenization procedure provides scattering coefficients that are valid over a much larger frequency range than the usual first-order procedure. The frequency well below which the effective description is valid is compared with the lower bound of the first Bragg bandgap when the profile is approximated by a two-step function of identical indicator function, i.e., two different cross-sectional areas over the same length. This validity limit is then questioned, particularly with a focus on impedance modeling. This article attempts to facilitate the engineering use of Willis materials.

Surface Love-type waves propagating through viscoelastic functionally graded media.

This paper deals with the solution of the model equations, which describes the propagation of the surface Love-type waves in a waveguide structure consisting of a lossy isotropic inhomogeneous layer placed on a viscoelastic homogeneous substrate. The paper points to the possibility of using the triconfluent Heun differential equation to solve the model equation. The exact analytical solution within the inhomogeneous layer is expressed by the triconfluent Heun functions. The exact solutions are general in the sense that only the internal parameters of the triconfluent Heun functions can change the spatial dependencies of the material parameters in the inhomogeneous layer's thickness direction. Based on the comparison, the limits of the WKB method applicability are discussed. It is further demonstrated that substrate losses affect the dispersion characteristics only to a small extent. Using examples in which the surface layer is represented by functionally graded materials, it was shown that the distance between the modes can be influenced through those materials.

[Urgent thyroidectomy for a mechanical syndrome caused by a toxic nodular goiter--a case report]. / Akutní tyroidektomie pro mechanický syndrom pri toxické nodózní strume--kazuistika.

We present a case of emergency surgery of an 86-year-old patient with an extensive cevicomediastinal toxic nodular goiter. Acutely onset mechanical syndrome during hospitalization of the patient in another department for a different diagnosis (vertebrogenic algic syndrome of Th-L spine) warranted acute intubation and mechanical ventilation. After the transfer of the patient to our department, we performed total thyroidectomy. All published cases of acute compression syndrome with respiratory insufficiency involve anaplastic carcinoma transformation, fast growing lymphoma, injuries with an intraglandular haemorrhage or infected cysts. In this case the reason was the benign disease of the thyroid gland.

Severe complications following intravesical BCG instillation.

In patients with urinary bladder carcinoma, the intravesical BCG instillation is widely used. We present two cases of severe pulmonary afflictions developed during this treatment. The possible mechanisms of etiology are discussed and the classification of the intravesical BCG treatment side effects is suggested.

[Cytodiagnosis of bone tumors]. / Cytodiagnostika kostních nádoru.

Fine needle biopsy was performed in 48 patients suffering from X-ray detected osteolytic lesions, during two years. A representative sample was obtained in 38 of them (79.2 percent). Cytologic conclusions could be proved in 35 patients by histology or clinical finding of primary tumour (in cases with bone secondaries). Cytologic diagnosis was correct in 30 patients (87.7 per cent). Especially good results were found out in bone metastases, plasmacytomas, and Ewing's sarcomas. Fine needle biopsy is to be recommended as an integral part of complex diagnosis of bone tumours.

[Helicobacter pylori after proximal selective vagotomy]. / Helicobacter pylori po proximální selektivní vagotomii.

The authors examined histologically in 40 patients after proximal selective vagotomy on account of duodenal ulceration specimens of the antral mucosa for the presence of Helicobacter pylori. The latter was detected in 38 (95%) patients. The intensity of colonization evaluated semiquantitatively was not directly related to the dyspeptic complaints. No relapses of ulcers were observed and the author's experience does not confirm the theory of a direct part played by Helicobacter in the manifestation of duodenal ulceration in patients after proximal selective vagotomy.

[Midline granuloma]. / Problematika midline-granulomu.

Midline malignant granuloma is the term used for a histogenetically heterogeneous group of diseases characterized by progressing destruction of tissues of the sinonasal area. The difficulty of differentiation of basic clinical pathological units included in this group, which is of fundamental importance for the subsequent therapeutic procedure, is demonstrated on two cases of Wegener's granulomatosis and sinonasal pleomorphous reticulosis.

[An osteoclastoid variation of a giant-cell tumor of the thyroid gland]. / Osteoklastoidní varianta obrovskobunecného nádoru stítné zlázy.

A thyroid tumour in a 58 year-old woman was studied by light and electron microscopy and immunohistology. Initial diagnosis of anaplastic osteoclastoid carcinoma had to be changed to malignant fibrous histiocytoma. Histogenetical evaluation was discussed.

[Ossifying adrenocortical carcinoma with myelolipoma]. / Osifikující adrenokortikální karcinom s myelolipomem.

In a 25-year-old female in adrenocortical carcinoma with a myelolipoma and areas of ossification was removed by operation. The carcinoma did not penetrate the myeloadipose structure. The finding of an actively growing bone within the stroma of the adenocarcinoma can be explained by the local action of androgens produced by the tumour tissue.