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Abstract Control of electrical doping is indispensable in any semiconductor device, and both efficient hole and electron doping are required for many devices. In organic semiconductors, however, electron doping has been essentially more problematic compared to hole doping because in general organic semiconductors have low electron affinities and require dopants with low ionization potentials that are often air-sensitive. Here, we adapt an efficient molecular doping method, so-called ion-exchange doping, to dope electrons in a polymeric semiconductor. We initially reduce the polymeric semiconductor using one electron transfer from molecular dopants, and then the ionized dopants in the resulting air-unstable films are replaced with secondary ions via cation exchange. Improved ambient stability and crystallinity of the doped polymeric semiconductors are achieved when a specific bulky molecular cation was chosen as the secondary ion, compared to conventional methods. The presented strategy can overcome the trade-off relationship between reducing capability and ambient stability in molecular dopants, and a wider selection of dopant ions will help to realize ambient-stable electron conductors.

1,3-Dimethyl-2,3-dihydrobenzo[d]imidazoles, 1H, and 1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazoles, 12, are of interest as n-dopants for organic electron-transport materials. Salts of 2-(4-(dimethylamino)phenyl)-4,7-dimethoxy-, 2-cyclohexyl-4,7-dimethoxy-, and 2-(5-(dimethylamino)thiophen-2-yl)benzo[d]imidazolium (1g–i+, respectively) have been synthesized and reduced with NaBH4 to 1gH, 1hH, and 1iH, and with Na:Hg to 1g2 and 1h2. Their electrochemistry and reactivity were compared to those derived from 2-(4-(dimethylamino)phenyl)- (1b+) and 2-cyclohexylbenzo[d]imidazolium (1e+) salts. E(1+/1•) values for 2-aryl species are less reducing than for 2-alkyl analogues, i.e., the radicals are stabilized more by aryl groups than the cations, while 4,7-dimethoxy substitution leads to more reducing E(1+/1•) values, as well as cathodic shifts in E(12•+/12) and E(1H•+/1H) values. Both the use of 3,4-dimethoxy and 2-aryl substituents accelerates the reaction of the 1H species with PC61BM. Because 2-aryl groups stabilize radicals, 1b2 and 1g2 exhibit weaker bonds than 1e2 and 1h2 and thus react with 6,13-bis(triisopropylsilylethynyl)pentacene (VII) via a “cleavage-first” pathway, while 1e2 and 1h2 react only via “electron-transfer-first”. 1h2 exhibits the most cathodic E(12•+/12) value of the dimers considered here and, therefore, reacts more rapidly than any of the other dimers with VII via “electron-transfer-first”. Crystal structures show rather long central C–C bonds for 1b2 (1.5899(11) and 1.6194(8) Å) and 1h2 (1.6299(13) Å).

Background: While frequent or occasional symptomatic intradialytic hypotension (IDH) may influence patient well-being, its effects on survival-independent of comorbidities-has not previously been investigated. In this study, therefore, our objective was to assess the effect of frequent IDH (f-IDH) or occasional IDH (o-IDH) on survival., Methods: During a 10 month run-in period in 1998, 77 patients with f-IDH (> or =10 hypotensive events/10 months, responding only to medical intervention) and 101 patients with o-IDH (1 or 2 events/10 months) were identified among all 958 patients of a dialysis network. Eighty-five patients who had no hypotensive episodes (no-IDH) during this run-in phase served as controls. Patients were followed for a median of 27 months (range: 0.3-37) and survival of patients in the three groups was compared by log-rank test. Independent association of f-IDH and o-IDH with survival, compared with no-IDH, was assessed by a proportional hazards model that included patient demographics, laboratory data and antihypertensive medication as well as comorbidity., Results: Forty-five patients (58%) with f-IDH, 47 (47%) with o-IDH and 33 (39%) with no-IDH died during the follow-up. Mortality rates (deaths/100 patient years) were 37 (log-rank P = 0.013 vs no-IDH), 26 (log-rank P = 0.375 vs no-IDH) and 21 in the three groups, respectively. This indicates significantly decreased survival in patients with f-IDH as compared to those with no-IDH. In multivariate proportional hazards regression, however, where age, sex, time spent on dialysis, presence of coronary heart disease, diabetes, Kt/V, albumin level and use of beta-blockers, calcium-channel blockers and long-acting nitrates has been adjusted for, neither f-IDH nor o-IDH was associated with survival., Conclusions: Mortality in patients with f-IDH is significantly higher than in those without such events. After adjustments for covariates, however, there is no independent effect of frequent or occasional episodes of IDH on mortality.

Background: Symptomatic dialysis hypotension (DH) continues to be a common problem. By comparing patients prone and resistant to DH, several dialysis session and patient related characteristics have been identified that confer susceptibility to DH. Less is known, however, about the comparison of patients with frequent and only occasional DH. The aim of the study was to compare clinical and dialysis-session- (complicated by hypotension) related data between those with frequent (fDH) and those with occasional dialysis hypotension (oDH)., Methods: Nine hundred and fifty-eight patients at 11 dialysis units were followed for 10 months and characteristics of patients with fDH (> or = 10 hypotensive events necessitating medical intervention) (n = 96) were compared to that of patients with oDH (1 or 2 events/10 months) (n = 130). Significant and independent predictors of fDH were obtained by multivariate logistic regression., Results: Significant differences between fDH vs. oDH patients were older age (64.4 vs. 56.9 years, p < 0.001), more females (66 vs. 46%, p < 0.005) in fDH. More fDH patients had diabetes (27 vs. 15%, p < 0.05) and less had glomerulonephritis (15 vs. 35%, p < 0.001) as the cause for ESRD. Coronary artery disease (68 vs. 50%, p < 0.01) and long-acting nitrate treatment (51 vs. 30%, p < 0.001) was more frequent while treatment with ACEI (33 vs. 48%, p < 0.05) or Ca-channel blockers (40 vs. 53%, p < 0.05) were less frequent in patients with fDH. Patients with fDH had higher serum phosphorus levels (1.99 vs. 1.79 mmol, p < 0.005). Dialysis session related data were similar but the hypotensive episode occurred earlier during dialysis in fDH (136 vs. 156 min, p < 0.01). In multivariate analysis, significant independent predictors of fDH were older age (OR = 1.04 [1.02-1.07]), lack of glomerulonephritis as renal diagnosis (2.63 [1.18-5.87]), high phosphorus levels (5.0 [2.45-10.0]), lack of use of Ca-channel blockers (2.09 [1.12-3.91]), and the use of nitrates (2.38 [1.24-4.55])., Conclusion: Features of the dialysis sessions complicated by DH seem to be similar between patients with fDH and oDH, while patient characteristics such as older age, renal diagnosis other than glomerulonephritis, higher serum phosphorus levels, use of nitrates, and lack of use of calcium channel blockers are significantly and independently associated with fDH., (Copyright 2002 S. Karger AG, Basel)

In their ten years renal biopsy material authors found nine cases of chronic glomerulonephritides with predominantly IgM deposition in the mesangium which reach the diagnosis of IgM nephropathy. This paper on the basis of a typical case deal with the immunopathology, diagnosis, prognosis and therapy of the disease.

Six patients with rapidly progressive glomerulonephritis were given plasmapheresis and peritoneal dialysis by manual technique. At the start of treatment the patients were in renal failure and all but two were practically anuric. Renal biopsy revealed glomerular sclerosis in 4 cases. One of the patients in whom segmental focal fibrosis was found, went into remission. In the other three cases extensive hyaline degeneration was present. One of them was placed on a dialysis program, two died with circulatory failure. In two cases no glomerular sclerosis was found, though extensive changes of the tissues were present. One of these patients went into remission, the other died from respiratory failure consequent upon recurrent pneumothorax and gross pulmonary infiltration. The only chance of success in the management of rapidly progressive glomerulonephritis is offered by the earliest possible diagnosis. In cases of glomerular sclerosis the chances are very poor.

Renal biopsy material of 50 patients suffering from IgA glomerulonephritis was studied by light microscopy, immunofluorescence and occasionally electron microscopy. Associated with a uniform immunohistological pattern mainly focal or diffuse mesangial proliferative glomerulonephritis was found. In addition to the glomerular changes the importance of frequent extraglomerular, mainly vascular and interstitial, alterations is stressed. In arterioles and arteries, deposition of a hyalinous substance was observed. Immunohistology revealed the presence of immunoglobulins and/or C3 in the vessels. In the interstitium fibrinogen/fibrin was often seen, accompanied by chronic inflammatory infiltration and fibrosis.

In case of 23 patients, who had been treated for 8.5 (2-10) months with intermittent peritoneal dialysis, the peritoneal dialysis was supplemented once or twice a week by haemodialysis for 8.5 months. This combined way of treatment was favourable in cases of hypervolemia and/or of increased level of substances of small molecular weight. The average duration of this kind of treatment was 4.1 (1.5-11) months. In the course of treatment the general condition of the patients improved. When they regained their optimal bodyweight, their blood pressure got normalized or their hypertony decreased or it could be regulated by drug therapy. At the effect of this treatment, the carbamid nitrate and serum creatinin significantly decreased and the serum total protein and albumin levels increased. Two of the patients underwent cadaver kidney transplantation, and 18 of them have been treated by hemodialysis, 3 of them are being treated in this combined way even now. The authors discuss the role of intermittent peritoneal dialysis and that of the combined treatment in the management of uremic patients.