Urinary complications of Crohn's disease

A 22-year review of 328 patients with Crohn's disease revealed 70 patients with urinary tract symptoms. Cystitis was the most common problem, occurring in 44 patients. The urinary tract infections were recurrent in most patients, usually with 3 or 4 attacks per year. Despite the persistence of urinary infection, only 3 patients developed chronic pyelonephritis. Forty-nine patients had intravenous urography, and many were found to have slight dilatation of the upper urinary tract on one side. Seven patients had hydronephrosis, 3 with pyonephrosis. Five of 6 patients who developed calculi had a bowel resection. All of the recovered calculi were oxalate stones, but 3 were passed spontaneously and not analyzed. Eight patients, 7 of them males, had an ileovesical fistula. In 1, the colon was also affected. It was unusual for these patients to have severe urinary symptoms. One patient had a fistula from the rectum to the urethra. Although 32 of the 70 patients were female, most of the severe complications occurred in men. Aggressive investigation is not indicated, nor is radical surgery required.     

Graphic Design for Computer Graphics

In concentrating on developing the computer's internal electronic communicative abilities, we have neglected the interface between the machine's display surface and the human viewer.     

The effects of processing and organoclay properties on the structure of poly(methyl methacrylate)-clay nanocomposites

A variety of nanocomposites were synthesised by bulk polymerisation of methyl methacrylate (MMA), and also by extrusion of poly(methyl methacrylate) (PMMA). These were characterised by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). We applied image analysis to the TEM images of these PMMA-clay nanocomposites to quantify their structures; an analysis was made of the resulting parameters to determine which were most useful for quantifying the microscale and nanoscale structures. Frequently, these quantitative results differed from those expected on the basis of WAXD, demonstrating the limitations of using diffraction data as the sole measure of nanocomposite structure. By combining the quantitative parameters from TEM with the WAXD data, we have explored the effects of processing conditions and organoclay properties on final nanocomposite structure. Factors examined included the effect of the reactivity of the surface modifiers, platelet size, the incorporation of excess modifier within the organoclay, and bulk polymerisation versus extrusion.     

Performance of a transversely excited pulsed HF laser

Operation of a pulsed HF laser with unique spectral and temporal behavior is reported.R-branch oscillation in the 1-0 band and peak multiline powers of 700 kW in 200-ns pulses have been observed. The gain of the 75-cm laser was measured to be 235 dB.     

Gain and relaxation studies in transversely excited HF lasers

The results of measurements of the spatial and temporal dependence of the gain of a pulsed HF laser are reported and are compared with those for CO2lasers. While the propagation in space of a locally excited gain medium is observed to be comparable for the two lasers, the time developments are vastly different. The extremely fast gain decay rates that were observed in the HF laser are shown to be a serious detriment to efficient high-power CW or long-pulse operation. Short pulse HF lasers, however, can be operated relatively efficiently at high energies. This was demonstrated by obtaining 350-mJ pulses from a 75-cm "pin" laser excited by 50-ns pulses from a Marx bank.