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The Kerr electrooptic effect is used to study the static electric-field distortions produced by various solid dielectric materials when introduced between parallel plate electrodes in a chlorobiphenyl liquid insulating medium. The results show that for an Aroclor of commercial purity, the field distortions are independent of the electrical properties of the solid. A weak dependence on the liquid impurity levels is shown. The surface current densities are also independent of the spacer materials. It is suggested that the measured surface current density is due to electrohydrodynamic (EHD) circulation of the liquid near the spacer. The resulting field distortions are discussed in the light of EHD motion of the liquid at the solid-liquid interface.

Operability of head and neck cancers is usually limited by extension to the base of the skull. Intracranial extension occurs by tumor growth along the perineurium of cranial nerves and along blood vessels or by direct bone erosion. Skull involvement usually is determined by radiologic evidence of destruction or enlargement of skull foramina. Of particular importance to the head and neck surgeon are those foramina that serve as possible conduits for intracranial extension of cancers of the maxillary and ethmoid sinuses, nasopharynx, palate, and face. Not infrequently disparity in size from the contralateral foramina, or absence of a particular foramina, will be interpreted as substantial evidence of intracranial tumor extension. The purpose of this study was to determine within individuals the normal diameter variations between pairs of the foramen ovale, foramen rotundum, pterygoid canal, and infraorbital canal. One hundred fifty tomograms of the anterior skull area were studied and classified into tumor and non-tumor groups. The frequency of nonvisualization and the range of normal size of each foramina were recorded.

The dependence of the static electric field distribution on dissolved water and air in the ranges 8-38 ppm and 0.5-4.6 percent by volume, respectively, for parallel plate electrodes, is examined for two chlorobiphenyls by means of the Kerr electro-optical technique. It is shown by measurement of the field distribution at 23°C for a 0.5-cm electrode separation and applied fields up to 160 kV/cm, dissociation of the water molecule results in an exponential distribution of positive space charge giving rise to an enhanced cathode field. The enhanced cathode field near breakdown own remains unchanged regardless of increasing water content corresponding to decreasing breakdown potential. Furthermore, it is shown that conduction is largely due to a unipolar process. The presence of air is shown to decrease the cathode field enhancement, this is thought to be due to recombination of the O2 molecules and H ions. The space charge limited current and breakdown phenomena are discussed in relation to the enhanced cathode field.

Long-Evans male rats copulated with single females until they allowed 30 min to elapse without achieving an intromission. At that point a ‘priming’ female was presented to each male for one intromission and then removed. Thirty seconds later either the original or priming female was reintroduced and the male allowed to copulate until he reached the satiation criterion again. The mean ejaculation frequency with the reintroduced priming female was 2·8 times greater than with the reintroduced original female (1·4 versus 0·41 ejaculations). In experiment II satiated males were again allowed one intromission with the priming female. Then the original female was reintroduced while the priming female was placed in a wire-mesh cage within the testing arena. The visual, olfactory, and auditory presence of the priming female did not enhance the ejaculatory capacity of the males with the reintroduced original female (0·36 versus 0·41 ejaculations in experiment I). The data are discussed in terms of revisions of the dual-mechanism theory of rat copulation originally proposed by Beach.

The need for nondelayed skin flaps from the chest for postoperative reconstruction and repair has increased considerably since the advent of combined irradiation and surgical therapy for treatment of cancer of the head and neck. Survival of these pedicled flaps is of paramount concern to the surgeon, as flap necrosis can be catastrophic for the patient. Many parameters have been evaluated to predict flap viability, but recent studies strongly suggest that the arterial blood supply of the pedicle is the most important factor in the success of immediate transposition. A study was performed in 19 cadavers to delineate the cutaneous vascular anatomy of the chest in order to determine precisely where the perforating vessels of the thorax and shoulders supply the pedicle region of medially-based and laterally-based pectoral flaps. On the basis of this study, modification of the design of these flaps is recommended.