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A microstrip patch antenna fed with two opposing microstrip lines is designed. The antenna has four cuts in its corners in order to introduce PIN diode to have a polarization agile antenna by changing the diodes states. Two vertical slots inside the patch are created for axial ratio and bandwidth enhancement. A separate DC biasing is inserted for proper operation of the diodes. Some antenna characteristics such as reflection coefficient, axial ratio, radiation pattern and gain are investigated and optimized through several parametric studies of the antenna geometry. This type of antenna is widely preferred in wireless communication systems.

This paper proposes a rectangular patch antenna fed from two orthogonal microstrip lines for polarization diversity. Different polarization states are achieved by using four PIN diodes placed at the patch corners. The PIN diodes are biased by an external DC circuitry to switch their states. This antenna has an operating frequency of around 2.4 GHz and can produce LHCP, RHCP, and linear polarization when the signal is fed from the horizontal feed and the vertical feed, so six polarization states are achieved. Antenna characteristics such as reflection coefficient, axial ratio, gain, and radiation pattern are being investigated through optimizing all antenna dimensions. This antenna is suitable for many wireless applications.

Isolation of the lateral ventricle has long been known to occur following ventriculitis. However, in recent years, functional isolation of the lateral ventricle has been seen with increasing frequency. Since 1979, eight patients without evidence of infection have required treatment for an isolated lateral ventricle following insertion of a contralateral ventricu-loperitoneal shunt at the Hospital for Sick Children, Toronto, Ontario, Canada. Two of these patients developed their hydrocephalus after intraventricular hemorrhage, and in six patients the hydrocephalus was associated with myelodysplasia. We specifically excluded patients in whom isolation of the lateral ventricle was secondary to ventriculitis. He feels that the isolated lateral ventricle following ventriculoperitoneal shunting may be due to a dynamic situation where overdrainage of the shunted ventricle leads to a functional obliteration of the foramen of Monro and subsequent enlargement of the contralateral lateral ventricle.

During the years 1975 to 1985, 10 patients underwent simultaneous repair of myelomeningocele and insertion of a ventriculoperitoneal shunt at the Hospital for Sick Children in Toronto. The technique for carrying out these procedures in the same operative setting will be described. None of the patients developed shunt infections or myelomeningocele repair breakdown in the follow-up period of 1 to 9 years. One patient died 9 days after operation secondary to aspiration. The remaining patients underwent neuropsychological testing during their follow-up periods and over 70% were found to have normal or slightly below normal intelligence and psychosocial development. The technique of simultaneous repair of a myelomeningocele and insertion of a ventriculoperitoneal shunt in infants with a myelomeningocele and concomitant hydrocephalus overt at birth is safe and should be carried out to decrease the risk of myelomeningocele repair breakdown and cerebrospinal fluid leak in such patients.

Isolation of the lateral ventricle has long been known to occur following ventriculitis. However, in recent years, functional isolation of the lateral ventricle has been seen with increasing frequency. Since 1979, eight patients without evidence of infection have required treatment for an isolated lateral ventricle following insertion of a contralateral ventriculoperitoneal shunt at the Hospital for Sick Children, Toronto, Ontario, Canada. Two of these patients developed their hydrocephalus after intraventricular hemorrhage, and in six patients the hydrocephalus was associated with myelodysplasia. We specifically excluded patients in whom isolation of the lateral ventricle was secondary to ventriculitis. We feel that the isolated lateral ventricle following ventriculoperitoneal shunting may be due to a dynamic situation where overdrainage of the shunted ventricle leads to a functional obliteration of the foramen of Monro and subsequent enlargement of the contralateral lateral ventricle.

In a comparative randomized double-blind study, 73 patients underwent myelography using iopamidol (36 patients) or metrizamide (37 patients) as contrast medium. The overall diagnostic adequacy of iopamidol myelography was found to be comparable to that of metrizamide myelography. The incidence of examinations graded as superior (64%) or adequate (36%) with iopamidol was equivalent to that with metrizamide (57% superior, 43% adequate). Adverse reactions after iopamidol myelography were fewer, less severe, and generally of shorter duration than those associated with metrizamide. In the iopamidol group, adverse reactions occurred in nine (25%) patients, all of whom experienced mild or moderate headache, one with nausea, vomiting, and fatigue. In the metrizamide group, adverse reactions occurred in 17 (46%) patients, all of whom experienced mild or moderate headache, six with nausea and vomiting and four with back and leg pain. Of nine individuals who underwent myelography using 300 mg I/ml metrizamide injected via lateral C1–C2 puncture, three experienced a toxic encephalopathy with confusion, dysphasia, headache, nausea, and vomiting, and a fourth individual suffered severe nausea, vomiting, fever, and irregular pulse. Encephalopathy was not observed in any of the 11 patients in whom myelography was performed via lateral C1–C2 puncture with a similar concentration of iopamidol. No seizures were encountered, and no clinically significant changes in laboratory studies were observed with either contrast medium.