An optimized polarization sensitive Salisbury screen

A transmission line equivalent circuit model for strip gratings is used to determine the performance of both conducting and resistive gratings. A polarization sensitive Salisbury screen is designed in which the space cloth is replaced by a resistive grating and the ground plane is replaced by a parallel conducting grating. The new Salisbury screen performs like the traditional screen for an incidentE-field parallel to the strips, but is transparent for the perpendicular polarization.     

Enhanced behavioral response to repeated d-amphetamine and personality traits in humans

We report herein the first documented case of gastrin-releasing peptide-positive neuroendocrine (NE) carcinoma of the extrahepatic biliary tract. An invasive tumor measuring 2.5 x 1.5 cm was located in the confluence portion of the cystic duct in a 70-year-old Japanese man. Histologically, the tumor was found to be composed of small polygonal cells which formed a solid and trabecular structure, and the frequencies of both mitoses and small necrotic areas were dominant. The tumor cells were immunoreactive to the NE markers chromogranin-A and neuron-specific enolase, as well as to carcinoembryonic antigen and gastrin-releasing peptide. Although a few cases of gastrin-releasing peptide-positive small-cell lung carcinoma have been documented, there have been no reports of gastrin-releasing peptide-positive NE carcinoma occurring in the gastrointestinal tract. We consider our case not merely to be of pathological interest, but also to have clinical and therapeutic implications.     

Perfluorocarbons: recent developments and implications for neurosurgery

Over the last 30 years, perfluorocarbons (PFCs) have been extensively investigated as oxygen carriers. Early studies indicated that these compounds could be used as blood substitutes or protective agents against ischemia. Adverse characteristics such as instability, short intravascular half-life, and uncertainties concerning possible toxicity precluded wide clinical application. However, advances in PFC technology have led to the development of improved second-generation oxygen carriers that incorporate well-tolerated emulsifiers (egg-yolk phospholipids). The authors review recent developments in this field and consider the potential role of PFCs in future neurosurgical practice. Diagnostic applications could include their use to assess cerebral blood flow, local oxygen tension, and brain metabolism or to achieve enhanced imaging and precise staging of inflammatory, neoplastic, or vascular disease processes by means of computerized tomography, ultrasonography, and magnetic resonance studies. Therapeutic applications could include cerebral protection, an adjunctive role in radiotherapy of malignant brain tumors, protection against air embolism, the preservation of organs for transplantation, and ventilatory support in head-injured patients with compromised lung function. In addition, PFCs have been used successfully as a tool in ophthalmic microsurgery and potentially they could fulfill a similar role in microneurosurgery.