Influence of electrical boundary conditions on profiles of acoustic field and electric potential of shear-horizontal acoustic waves in potassium niobate plates.

The profiles of an acoustic field and electric potential of the forward and backward shear-horizontal (SH) acoustic waves of a higher order propagating in X-Y potassium niobate plate have been theoretically investigated. It has been shown that by changing electrical boundary conditions on a surface of piezoelectric plates, it is possible to change the distributions of an acoustic field and electric potential of the forward and backward acoustic waves. The dependencies of the distribution of a mechanical displacement and electrical potential over the plate thickness for electrically open and electrically shorted plates have been plotted. The influence of a layer with arbitrary conductivity placed on a one or on the both plate surfaces on the profiles under study, phase and group velocities of the forward and backward acoustic waves in X-Y potassium niobate has been also investigated. The obtained results can be useful for development of the method for control of a particle or electrical charge movement inside the piezoelectric plates, as well a sensor for definition of the thin film conductivity.

Plate acoustic wave sensor for detection of small amounts of bacterial cells in micro-litre liquid samples.

Ultrasonic acoustic waves propagating in thin piezoelectric plates with free faces are used for bacteria detection in micro-litre liquid samples deposited on one of the plate surface. The limits of the detection at normal conditions are as low as 0.04% for highly diluted rich cultural Luria-Bertani broth (LB-media) in distillate water, 0.07% for bacterial cells in distillate water, and 0.6% for bacterial cells in LB-media. For all analytes the most probable detection mechanism is the change in liquid conductivity. Because of no using any sorbent film the long-term stability of the detection is expected as very high.

[Prevertebral abscess and endotracheal intubation in patients with infectious spondylitis of cervical vertebrae]. / Prevertebral'nyi abstsess i éndotrakheal'naia intubatsiia u bol'nykh s infektsionno-vospalitel'nymi spondilitami sheinogo otdela.

The course of hypostatic abscess in cervical spondylitis is analyzed, and its clinico-roentgenological manifestations are presented. The differential diagnosis between prevertebral abscess and thyroid tumors is described. The modes of application of endotracheal undulation in patients with cervical spondilitis and prevertebral abscess are suggested.

[Clinical picture, diagnosis and treatment of intervertebral osteochondritis]. / Klinika, diagnostika i lechenie mezhpozvonochnogo osteokhondrita.

25 patients with intervertebral osteochondritis (11-cervical, 5-thoracic, 9-lumbar) at the age of 30-70 years are analysed. Clinical features of osteochondritis locafed in different segments of the spine, are described. The fact that at the early stages of it's development, the disease is "X-ray negative", is stressed. The radioisotopic examination of the spine is highly effective in diagnosis of early stages of infective-inflammatory process of the intervertebral disks. The roentgenological characteristics of different stages of the disease are provided. Conservative methods, including antibiotics, bedding, orthopaedic methods are most important in the treatment of intervertebral osteochondritis. Surgical treatment is indicated in case of spine compression and instability of a damaged segment of the spine. In case of a proper diagnosis and adequate treatment the outcome is favorable.