Spontaneous formation of three-dimensionally ordered Bi-rich nanostructures within GaAs1-x Bi x /GaAs quantum wells.

In this work, we report on the spontaneous formation of ordered arrays of nanometer-sized Bi-rich structures due to lateral composition modulations in Ga(As,Bi)/GaAs quantum wells grown by molecular beam epitaxy. The overall microstructure and chemical distribution is investigated using transmission electron microscopy. The information is complemented by synchrotron x-ray grazing incidence diffraction, which provides insight into the in-plane arrangement. Due to the vertical inheritance of the lateral modulation, the Bi-rich nanostructures eventually shape into a three-dimensional assembly. Whereas the Bi-rich nanostructures are created via two-dimensional phase separation at the growing surface, our results suggest that the process is assisted by Bi segregation which is demonstrated to be strong and more complex than expected, implying both lateral and vertical (surface segregation) mass transport. As demonstrated here, the inherent thermodynamic miscibility gap of Ga(As,Bi) alloys can be exploited to create highly uniform Bi-rich units embedded in a quantum confinement structure.

Size-dependent optical properties of BaTiO3-SrTiO3 superlattices.

Artificial BaTiO(3)-SrTiO(3) superlattices with stacking periodicity varying between 27 and 1670 A in separate films were grown on MgO substrates by pulsed laser deposition. Both the static and active optical properties were found to be sensitive on the stacking periodicity. Birefringence decreased with increasing individual layer thickness due to relaxation of the interface originated stress. The electro-optic response also showed a layer thickness dependence, reaching a maximum at an individual layer thickness of 13 unit cells.

R2R-printed inverted OPV modules--towards arbitrary patterned designs.

We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm(2) to 96.5 cm(2). A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm(2) sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality.

Bioremediation of petroleum hydrocarbon-contaminated soil by composting in biopiles.

Composting of contaminated soil in biopiles is an ex situ technology, where organic matter such as bark chips are added to contaminated soil as a bulking agent. Composting of lubricating oil-contaminated soil was performed in field scale ( [Formula: see text] m(3)) using bark chips as the bulking agent, and two commercially available mixed microbial inocula as well as the effect of the level of added nutrients (N,P,K) were tested. Composting of diesel oil-contaminated soil was also performed at one level of nutrient addition and with no inoculum. The mineral oil degradation rate was most rapid during the first months, and it followed a typical first order degradation curve. During 5 months, composting of the mineral oil decreased in all piles with lubrication oil from approximately 2400 to 700 mg (kg dry w)(-1), which was about 70% of the mineral oil content. Correspondingly, the mineral oil content in the pile with diesel oil-contaminated soil decreased with 71% from 700 to 200 mg (kg dry w)(-1). In this type of treatment with addition of a large amount of organic matter, the general microbial activity as measured by soil respiration was enhanced and no particular effect of added inocula was observed.

Comparison of echocardiography and radionuclide ventriculography in the follow-up of left ventricular systolic function in adult lymphoma patients during doxorubicin therapy.

OBJECTIVES: To compare echocardiography (ECHO) and radionuclide ventriculography (RVG) in the monitoring of left ventricular systolic function during doxorubicin therapy in adult lymphoma patients. DESIGN: Prospective study. SETTINGS: University hospital. SUBJECTS: A total of 28 adult patients who received doxorubicin to a cumulative dose of 400-500 mg m(-2). MAIN OUTCOME MEASURES: ECHO and RVG were performed at baseline and after cumulative doxorubicin doses of 200, 400 and 500 mg m(-2). RESULTS: At baseline, the mean (+/-SE) left ventricular ejection fractions (LVEF) were 58 +/- 1.3, 71 +/- 1.8 and 58 +/- 1.7% as determined by RVG, M-mode ECHO and two-dimensional (2D) ECHO, respectively. After the cumulative doxorubicin dose of 500 mg m(-2) LVEF decreased to 49.6 +/- 1.7% (RVG) (P < 0.001), 62 +/- 1.6% (M-mode) (P=0.006) and 52.5 +/- 1.3% (2D ECHO) (P=0.036). Although a significant correlation between LVEF determined by RVG and M-mode ECHO (r=0.615, P=0.002) and a trend between RVG and 2D ECHO (r=0.364, P=0.096) were observed, there were substantial differences in the results of individual patients. In the agreement analysis using the method of Bland and Altman there was a mean difference of 12% units with the upper limit of agreement +26% units and the lower limit of agreement -2.1% units for LVEF determinations with M-mode ECHO and RVG, and a mean difference of 3.3% units with upper and lower limits of agreement +19.6 and -13.1% units for LVEF determinations with 2D ECHO and RVG, respectively. CONCLUSION: We found only a moderate agreement between left ventricular systolic function determined by ECHO and RVG methods. Thus, in the follow-up of left ventricular function in adult patients during doxorubicin therapy, the guidelines based on LVEF measurement by RVG cannot be applied to ECHO. Consequently, RVG remains the method of choice in this context.

Natriuretic peptides during the development of doxorubicin-induced left ventricular diastolic dysfunction.

OBJECTIVES: To investigate changes in plasma atrial natriuretic peptide (ANP), N-terminal pro-atrial natriuretic peptide (NT-pro-ANP) and brain natriuretic peptide (BNP) during the development of doxorubicin-induced left ventricular systolic and diastolic dysfunction as measured by echocardiography (ECHO). DESIGN: Prospective study. SETTING: University hospital. SUBJECTS: Twenty-eight adult patients with non-Hodgkin's lymphoma, who received doxorubicin to the cumulative dose of 400-500 mg m(-2). MAIN OUTCOME MEASURES: The relationship between plasma natriuretic peptides and systolic and diastolic ECHO indices after the cumulative doxorubicin doses of 200, 400 and 500 mg m(-2). RESULTS: Left ventricular ejection fraction (LVEF, by 2D ECHO) decreased from 58 +/- 1.7 to 52.5 +/- 1.3% (P=0.036) and fractional shortening (FS) from 34.6 +/- 1.4 to 27.8 +/- 0.9% (P=0.002). Peak E wave velocity decreased from 63.3 +/- 3.2 to 51.3 +/- 2.6 cm s(-1) (P=0.008) resulting in a statistically nonsignificant decrease in E/A ratio from 1.08 +/- 0.01 to 0.85 +/- 0.07. A significant decrease was observed in the percentage of left ventricular filling during the 1/3 of diastole (1/3FF) from 42.2 +/- 1.7 to 36.5 +/- 2.0% (P < 0.001). LV end systolic diameter increased from 32 +/- 1 to 38 +/- 1 mm (P=0.011), whereas left atrial (LA) diameter remained unchanged. Peak filling rate decreased from 4.4 +/- 0.2 to 4.0 +/- 0.2 stroke volume s(-1) (SV s(-1)) (ns). Plasma levels of ANP increased from 16.4 +/- 1.3 to 22.7 +/- 2.4 pmol L(-1) (P=0.002), NT-pro-ANP from 288 +/- 22 to 380 +/- 42 pmol L(-1) (P=0.019) and BNP from 3.3 +/- 0.4 to 8.5 +/- 2.0 pmol L(-1) (P=0.020). There was a significant inverse correlation between the decrease in FS and the increases in plasma NT-pro-ANP (r= -0.524, P=0.018) and plasma BNP (r=0.462, P=0.04) and between the decrease in PFR and the increases in plasma ANP (r= -0.457, P=0.043) and plasma NT-pro-ANP (r= -0.478, P=0.033). Furthermore, after doxorubicin therapy, significant inverse correlations were observed between E/A ratio and plasma ANP (r= -0.535, P=0.008), between E/A ratio and plasma NT-pro-ANP (r= -0.432, P=0.04) and between E/A ratio and plasma BNP (r= -0.557, P=0.006) as well as between 1/3FF and plasma BNP (r= -0.493, P=0.017). There was also a trend for correlation between LA diameter and plasma BNP (r=0.395, P=0.062) and peak E wave velocity and plasma BNP (r= -0.414, P=0.05), respectively. However, no significant correlations were observed between any of the systolic parameters and natriuretic peptide levels. CONCLUSIONS: The results of this prospective study show that during the evolution of doxorubicin-induced LV dysfunction the secretion of natriuretic peptides is more closely associated with the impairment of left ventricular diastolic filling than with the deterioration of LV systolic function.

Acute neurohumoral and cardiovascular effects of idarubicin in leukemia patients.

Idarubicin has been shown to have similar or superior antileukemic activity to daunorubicin with less cumulative cardiotoxicity. However, data of acute cardiovascular effects of idarubicin are scanty but may have clinical significance in predicting late cardiovascular complications. In the present study we evaluated prospectively acute neurohumoral and cardiovascular effects of idarubicin containing induction chemotherapy in 10 patients with newly diagnosed AML or MDS. Idarubicin was administered intravenously 12 mg/m2 on d 1, 3 and 5 as a part of the induction chemotherapy. Serial measurements of plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were performed at baseline and the day following each idarubicin infusion. Echocardiography was performed to assess cardiac systolic and diastolic function. Signal averaged electrocardiography (ECG) was recorded to observe myocardial late potentials associated with possible myocardial injury. In addition, ambulatory ECG recording was performed to assess arrhythmias. Plasma concentrations of ANP increased from 18.2 +/- 1.5 pmol/l to 27.8 +/- 3.5 pmol/l (p = 0.011), to 30.2 +/- 3.0 pmol/l (p = 0.002) and to 40.8 +/- 6.0 pmol/l (p = 0.006) after the first, second and third doses of idarubicin, respectively. Similarly, plasma concentration of BNP increased from 6.2 +/- 1.9 to 9.0 +/- 1.8 pmol/l (p = 0.049) and 17.5 +/- 8.1 pmol/l (p = 0.203) after the first and third idarubicin infusion. Concomitantly, there was a trend towards an increase in left ventricular end diastolic diameter (LVEDD) (50.2 +/- 1.8 to 54.4 +/- 2.2 mm, p = 0.070). The increase in plasma BNP concentrations correlated significantly with the increase in LVEDD (r = 0.624; p = 0.002). No significant ECG changes or arrhythmias were associated with idarubicin infusions except in 1 patient who developed abnormal myocardial late potentials. Our results show that idarubicin causes acute neurohumoral activation associated with increased LVEDD indicating subclinical myocardial dysfunction. Whether these acute changes predict late clinical cardiomyopathy should be evaluated in prospective studies with larger number of patients and with higher cumulative anthracycline doses.