A 1D conical nanotubular TiO2/CdS heterostructure with superior photon-to-electron conversion.

Herein, a new strategy to efficiently harvest photons in solar cells is presented. A solar cell heterostructure is put forward, based on a 1D conical TiO2 nanotubular scaffold of high aspect ratio, homogenously coated with a thin few nm layer of CdS light absorber using atomic layer deposition (ALD). For the first time, a large variety of conical nanotube layers with a huge span of aspect ratios was utilized and ALD was used for the preparation of a uniform CdS coating within the entire high surface area of the TiO2 nanotubes. The resulting 1D conical CdS/TiO2 tubular heterostructure acts as a sink for photons. Due to the multiple light scattering and absorption events within this nanotubular sink, a large portion of photons (nearly 80%) is converted into electrons. It is the combination of the scaffold architecture and the light absorber present on the high surface area as a very thin layer, the optimized charge transport and multiple optical effects that make this heterostructure very promising for the next generation of highly performing solar cells.

[Impact of acute fluid restriction on levels of natriuretic peptides in patients on a chronic dialysis program]. / Vliv akutni restrikce tekutin dialýzou na hladinu natriuretických peptidu u nemocných v chronickém dialyzacním programu.

In order to assess an impact of acute changes in blood volume on levels of B-type natriuretic peptides (BNP and NT-proBNP) 30 patients with a heart disease and chronic renal insufficiency on chronic dialysis program were assessed. An acute fluid restriction of 3750 ml on an average lead to decreased filling of the left heart ventricle (echocardiography revealed a reduced size of the left atrium, change in E/A parameters and deceleration time, and decreased end-diastolic volume of the left ventricle). Prior to dialysis normal levels of BNP (2.58 +/- 1.21 pg/ml) and elevated levels of NT-proBNP (193.2 +/- 117.7 pg/ml) had been indicated. Following dialysis a statistically significant decrease of BNP concentration in venous blood was proved, however it was "masked" by hemoconcentration. NT-proBNP level in venous blood remained unchanged. Correlation between BNP and NT-proBNP was not proved before dialysis nor after it. Correlation between BNP levels and echocardiographic parameters was not confirmed and a weak negative correlation with ejection fraction was proved in NT-proBNP. A BNP assessment could play an important role in the evaluation of acute changes in heart compensation. On the other way, NT-proBNP concentration is stable and is a long term marker of synchronisation of fluid circulation and function of the left ventricle. An importance of its assessment is probably rather prognostic.

[Preoperative and postoperative care in diabetics]. / Predoperacní a pooperacní péce o diabetika.

The submitted paper should serve as a basis for recommended procedures of preoperative and postooperative care of diabetics. It contains the algorithm of preoperative preparation of diabetics focused on quantification of the risk of surgery. The diabetologist is the consultant of the surgeon who participates in the preparation of the patient for urgent as well as elective surgery. The procedures differ with regard to the type of diabetes. The authors mention in more detail the problem of preoperative care of operated diabetics and finally also monitoring and therapy of diabetics during the postoperative period.

[Special problems in diabetics with hypertension]. / Nekteré zvlástní problémy u diabetiku s hypertenzí.

Diabetes and hypertension are independent risk factors of coronary heart disease as well as of other cardiovascular diseases, and their combination substantially enhances the risk. Hypertension is twice to four times as frequent in diabetics than in the non-diabetic population. The most frequent form is essential hypertension which affects the relatively most numerous group of the II diabetics but may occur also in type I diabetics. Insulin dependent diabetics suffer more frequently from "renal diabetic hypertension" and tend to develop hyporeninaemic hypoaldosteronism. Other types of hypertension found in diabetics are systolic hypertension and hypertension with orthostatic hypotension. In an effort to improve the adverse prognosis of diabetics with hypertension it is essential to pay systematic attention to early detection of high blood pressure, its differential diagnosis and treatment, and to detect, and if possible eliminate, other risk factors of cardiovascular diseases.