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We present intermediate-band solar cells manufactured using quantum dot technology that show for the first time the production of photocurrent when two sub-band-gap energy photons are absorbed simultaneously. One photon produces an optical transition from the intermediate-band to the conduction band while the second pumps an electron from the valence band to the intermediate-band. The detection of this two-photon absorption process is essential to verify the principles of operation of the intermediate-band solar cell. The phenomenon is the cornerstone physical principle that ultimately allows the production of photocurrent in a solar cell by below band gap photon absorption, without degradation of its output voltage.

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The Authors' series of 44 patients transplanted after peritoneal dialysis suggests that the results of renal transplantation are comparable to those on hemodialysis.

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Acceptance of peritoneal dialysis as a standard modality of therapy for end-stage renal disease (ESRD) was initially slow due to various technical problems and the difficulty of quantitating peritoneal membrane function. Development of reliable, permanent access to the peritoneum and the availability of dependable automated equipment stimulated the development of intermittent peritoneal dialysis (IPD), which demonstrated initial success. However, the failure rate was noted to increase with time, primarily due to insufficient dialysis and malnutrition. The introduction of continuous ambulatory peritoneal dialysis (CAPD) allowed better clearances and the maintenance of a more physiologic steady state. However, the twin problems of inconvenience and frequent infections proved to be significant. Continuous cyclic peritoneal dialysis (CCPD) was then developed to allow exchanges at night on a more convenient basis, reduce the rate of peritonitis by circumventing some of the technical disadvantages of CAPD, and decrease the stress on any helpers who may be involved. Experience with CCPD has demonstrated acceptable control of nitrogenous waste products, fluid balance, adequate maintenance of nutrition in the great majority of patients, and satisfactory maintenance of hemoglobin and acid-base balance. CCPD also offers flexibility of prescription accomplished by varying the frequency and length of nocturnal automated cycles. The preliminary experience with peritoneal kinetic modeling suggests that quantitation of peritoneal function will be significantly improved in the future and that standards of adequacy of dialysis will be more precisely defined.

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A prospective, uncontrolled study was designed to evaluate the changes in visual efficiency among insulin-requiring diabetic patients undergoing peritoneal and hemodialysis. Of the 112 patients (63% adult onset and 37% juvenile onset diabetics) studied chronologically, 63% were treated with hemodialysis and 37% with peritoneal dialysis. The mean distribution of sex, age, observation period and initial visual function were the same in the peritoneal and hemodialysis subpopulations, but more juvenile onset diabetics were treated with peritoneal dialysis. Preservation of vision correlated well with overall blood pressure control in all dialysis groups. Loss of vision was independent of the dialysis modality, of glucose control, and of the type of onset of diabetes.

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Total parathyroidectomy and autotransplantation of tissue to the forearm was practiced in 50 chronic renal failure patients as treatment for secondary hyperparathyroidism. Four hyperplastic glands were removed in all cases. Followup observation ranged from 3 to 42 months. Serum parathyroid hormone, alkaline phosphatase, calcium and phosphorus levels decreased significantly following the procedure (P less than 0.005) and remained stable during the period of observation. Significant bone pain present in 26 patients improved or ceased in 19; pruritus, present in 39 patients, universally improved. Strong radiographic suggestion of secondary hyperparathyroidism, present in 38 patients, improved or disappeared in 17. Three patients remained functionally hyperparathyroid, requiring further tissue removal. Autograft function 3 to 7 days after transplantation was demonstrated in 3 cases by differential parathyroid hormone concentration determinations. Essentially all patients experienced symptomatic improvement after surgery and most showed objective evidence of improved calcium-phosphorus metabolism and bone healing.

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Continuous cyclic peritoneal dialysis (CCPD) was designed to reduce the high incidence of peritonitis and eliminate the multiple interruption created by dialysis exchanges during the day needed for CAPD, while maintaining the quality of dialysis. Three nocturnal cycles with 2 liters of dialysate lasting 3 hours each are provided by an automated cycler while the patient sleeps. Two liters are left in the abdomen in the morning. Only one daily connection and one disconnection are required between the peritoneal catheter and the cycler line. Our 84 patient months experience with 14 patients reveals a low incidence of peritonitis (1 per 42 patient months), satisfactory ultrafiltration rates and clearances that compare favorably with those of CAPD (Curea 67, Ccreatinine 58, and CB12 45 L/wk). Blood pressure control has been excellent while most patients enjoy liberal diets. This preliminary study suggests that CCPD may indeed reduce the rate of peritonitis, provide excellent clearance and ultrafiltration, allow more free time to the patient and maintain a steady physiological state.

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A patient with severe and protracted post renal biopsy hemorrhage is presented. The bleeding site was identified by renal arteriography and the hematuria was promptly controlled by Gelfoam embolization of the artery leading directly to the bleeding site. This aggressive approach should be considered early to control hematuria and expanding perirenal hematomas in selected cases of protracted post renal biopsy hemorrhage.

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The authors designed a double-blind hemodialysis protocol consisting of hemodialysis or sham dialysis twice weekly for 10 weeks, respectively. Four patients were carefully selected and evaluated clinically and on the Clinical Global Impression Scale. Three did not show any signs of improvement, and one patient demonstrated questionable improvement but decompensated after 12 additional weeks of hemodialysis. This preliminary study does not confirm the hypothesis that hemodialysis is effective in controlling psychotic symptoms. The authors consider other possibly beneficial treatments for schizophrenia.

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The experience with intraperitoneal infusion of non-absorbable steroids (triamcinolon hexacetonide) in the treatment of intractable hemodialysis-associated ascites and severe sterile peritonitis is presented. All patients uniformly responded to therapy with prolonged periods of remission and no significant complications. We conclude that intraperitoneal steroidal administration offers an effective modality of therapy in the treatment of these complications.

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