Theory of MSW transducers

This is a review of two electrical equivalent circuits for multi-element magnetostatic wave transducers. The two circuit models are identified as a transmission line and a two terminal model. Both models have been extended to all three principal MSW modes of propagation to the point where computer programs have been written to plot phase and amplitude response as measured by commercial network analyzers. A review is provided of the basic assumptions, similarities and differences, advantages and disadvantages, and limitations of the two models. The useful range of them covers many cases of practical interest in the one to twelve Ghz frequency range.     

Macrosegregation in castings rotated and oscillated during solidification

The macrosegregation present in stationary, rotated, and oscillated castings of Al-3 wt pct Ag was determined by measuring the distribution of radioactive silver added to the melt. Considerable scatter was observed in the measurements, the scatter being dependent on the sampling technique used. It was found that no significant macrosegregation was present in the stationary and rotated castings. Extensive macrosegregation was detected in the oscillated casting. For the oscillating case the macrosegregation can be accounted for on the basis of the long range movement of dendrite fragments which break and/or melt off in the solid-liquid interface region. This movement is a direct result of turbulent waves associated with the oscillation. The maximum silver concentration is shown to be related to the columnar-to-equiaxed transition.     

Microsegregation in unidirectionally cast copper alloys

Solute concentrations in dilute Cu-Ni, Cu-Ag, and Cu-Sb alloys have been measured at the centers of primary and secondary dendrites and in the interdendritic regions, using electron probe microanalysis. It was found that in the Cu-Ni alloys, the segregation ratio was independent of distance from the chill and alloy composition, with the effective distribution coefficient differing significantly from the equilibrium value. In the Cu-Ag and Cu-Sb alloys the segregation ratio was markedly dependent on distance from the chill and alloy composition, being greatest farthest from the chill. The microsegregation associated with secondary dendrite branches differs from that of the primary branches for the same spacing, the amount depending on the system. One ternary alloy, Cu-Ag-Ni, was examined and it was demonstrated that the presence of a second solute markedly influenced the microsegregation of the first solute. Measurements were made of primary and secondary dendrite arm spacing in the castings for increasing distances from the chill. The spacings are considered in terms of pouring temperature, freezing rate, and cooling rate. It was found that, in general, no simple relationship existed between dendrite spacing and the above variables within the range of conditions investigated in this study. Solute distributions across individual primary dendrite stalks were determined and related to curves calculated on the basis of complete mixing and diffusion solute transport in the liquid. For the Cu-Ag and Cu-Sb alloys(k < 1), good agreement was obtained between the experimental and complete mixing curves, using an effective value fork in the calculations determined from the dendrite center concentrations. For the Cu-Ni alloys(k > l), only a part of each experimental curve could be fitted by either the complete mixing or diffusion transport calculated curves.     

Analysis of a large pedigree with elliptocytosis, multiple lipomatosis, and biological false-positive serological test for syphilis

Elliptocytosis, multiple lipomatosis, and biological false-postive serological test for syphilis (BFPSTS) were found in a single individual. One hundred eighty relatives were tested for the three diseases: 74 were typed for seven blood group antigens, and 58 were typed for four electrophoretic enzyme markers. Likelihood analysis of the pedigree data confirmed independent dominant inheritance for elliptocytosis and lipomatosis. BFPSTS appears dominant, but the analysis was inconclusive. No linkages were found between any disease gene and any marker gene. Two female pedigree members with BFPSTS developed systemic lupus erythematosus, a finding in agreement with the previously described association. The analysis did not lead to any conclusions about the causal relationship between the two traits.     

Antibodies to Candida after operations on the heart

In order to determine the frequency of hypoxaemia and to evaluate the role of increased closing capacity in producing hypoxaemia in patients with cirrhosis of the liver, 13 patients with well-established cirrhosis were studied. Arterial blood gases, spirometry, lung volume, and closing capacity measurements were made with the patients in the seated and recumbent positions after exclusion of cardiopulmonary dysfunction. Four of 13 and six of 12 patients exhibited significant hypoxaemia in the seated and recumbent positions respectively. Five of 13 patients showed a closing capacity greater than predicted. This frequency of increased closing capacity was not higher than in a group of smokers of the same age. Unlike Ruff et al. (1971), we did not find a consistent relationship between hypoxaemia and closing capacity.     

A new method of treatment for mallet finger. A preliminary report

An infant with a typical Edwards syndrome and a modal chromosome number of 46 is reported. In all cells analyzed one chromosome G was missing and an additional chromosome similar to a pair No. 16 was present. The phenotype of the child indicates that the extra element is a translocation between G and 18 chromosomes as in one case described previously.     

Ulstrasonic monitoring for early diagnosis of air embolism during neurosurgical procedures (author's transl)

The sitting position of the patient offers many advantages to the neurosurgeon for operations at the posterior fossa, the upper cervical region, the Gasserian ganglion and the retroganglionic trigeminal root. Air embolism is however one of the greatest dangers during operations in this position. Air emboli occur more frequently than it is generally recognized. Most monitoring systems indicate the entrance of air at a late stage only. But early diagnosis and immediate therapy are of utmost importance. The use of an ultrasonic monitoring device for early diagnosis and the preoperative insertion of a right artrial catheter for immediate aspiration of the air are recommended.     

The organization and postnatal development of the commissural projection of the rat somatic sensory cortex

Anterograde and retrograde tracing experiments have been used to demonstrate the origin and terminal distribution of commissural fibers in the first somatosensory cortex (SI) of the rat. The commissural fibers originate from pyramidal cells of all layers, but predominantly from layers III and V. The fibers terminate in a series of approximately vertical bands. In each of these there are concentrations of terminals extending from the inner portion of the molecular layer to the deep portion of layer III as well as in the superficial part of layer V, and in layer VI. Discrete vertical bands of cortex are reciprocally connected across the midline to give both the origin and terminal regions of the projection a patchy or "columnar" appearance. The commissural fibers arise from and terminate in areas of the cortex that lie between and alongside the aggregations of granule cells that distinguish SI of the rat. No commissural fibers terminate within the aggregations of layer IV cells themselves but the more superficial terminal ramifications may come to overlie these aggregations. A heterotopic projection to the contralateral second somatosensory cortex has been observed and is similar in form to the homotopic projection to SI. Many commissural fibers have crossed the midline in the corpus callosum by the day of birth but lie in the underlying white matter and do not enter the cortical plate until at least the third postnatal day. During the first postnatal week these fibers grow somewhat diffusely into the maturing cortex and their topographic and laminar pattern of distribution attains its adult characteristics by the end of the first week. Commissural axons, thus, arise from immature cells but the maturation of cell form seems to precede the ingrowth of these axons and the acquisition of commissural synapses.