Elimination of charge carrier trapping in diluted semiconductors.

In 1962, Mark and Helfrich demonstrated that the current in a semiconductor containing traps is reduced by N/Nt(r), with N the amount of transport sites, Nt the amount of traps and r a number that depends on the trap energy distribution. For r > 1, the possibility opens that trapping effects can be nearly eliminated when N and Nt are simultaneously reduced. Solution-processed conjugated polymers are an excellent model system to test this hypothesis, because they can be easily diluted by blending them with a high-bandgap semiconductor. We demonstrate that in conjugated polymer blends with 10% active semiconductor and 90% high-bandgap host, the typical strong electron trapping can be effectively eliminated. As a result we were able to fabricate polymer light-emitting diodes with balanced electron and hole transport and reduced non-radiative trap-assisted recombination, leading to a doubling of their efficiency at nearly ten times lower material costs.

Selecting first-line bevacizumab-containing therapy for advanced breast cancer: TURANDOT risk factor analyses.

BACKGROUND: The randomised phase III TURANDOT trial compared first-line bevacizumab-paclitaxel (BEV-PAC) vs bevacizumab-capecitabine (BEV-CAP) in HER2-negative locally recurrent/metastatic breast cancer (LR/mBC). The interim analysis revealed no difference in overall survival (OS; primary end point) between treatment arms; however, progression-free survival (PFS) and objective response rate were significantly superior with BEV-PAC. We sought to identify patient populations that may be most appropriately treated with one or other regimen. METHODS: Patients with HER2-negative LR/mBC who had received no prior chemotherapy for advanced disease were randomised to either BEV-PAC (bevacizumab 10 mg kg(-1) days 1 and 15 plus paclitaxel 90 mg m(-2) days 1, 8 and 15 q4w) or BEV-CAP (bevacizumab 15 mg kg(-1) day 1 plus capecitabine 1000 mg m(-2) bid days 1-14 q3w). The study population was categorised into three cohorts: triple-negative breast cancer (TNBC), high-risk hormone receptor-positive (HR+) and low-risk HR+. High- and low-risk HR+ were defined, respectively, as having ⩾2 vs ⩽1 of the following four risk factors: disease-free interval ⩽24 months; visceral metastases; prior (neo)adjuvant anthracycline and/or taxane; and metastases in ⩾3 organs. RESULTS: The treatment effect on OS differed between cohorts. Non-significant OS trends favoured BEV-PAC in the TNBC cohort and BEV-CAP in the low-risk HR+ cohort. In all three cohorts, there was a non-significant PFS trend favouring BEV-PAC. Grade ⩾3 adverse events were consistently less common with BEV-CAP. CONCLUSIONS: A simple risk factor index may help in selecting bevacizumab-containing regimens, balancing outcome, safety profile and patient preference. Final OS results are expected in 2015 (ClinicalTrials.gov NCT00600340).

Studying flow close to an interface by total internal reflection fluorescence cross-correlation spectroscopy: quantitative data analysis.

Total internal reflection fluorescence cross-correlation spectroscopy (TIR-FCCS) has recently [S. Yordanov et al., Optics Express 17, 21149 (2009)] been established as an experimental method to probe hydrodynamic flows near surfaces, on length scales of tens of nanometers. Its main advantage is that fluorescence occurs only for tracer particles close to the surface, thus resulting in high sensitivity. However, the measured correlation functions provide only rather indirect information about the flow parameters of interest, such as the shear rate and the slip length. In the present paper, we show how to combine detailed and fairly realistic theoretical modeling of the phenomena by Brownian dynamics simulations with accurate measurements of the correlation functions, in order to establish a quantitative method to retrieve the flow properties from the experiments. First, Brownian dynamics is used to sample highly accurate correlation functions for a fixed set of model parameters. Second, these parameters are varied systematically by means of an importance-sampling Monte Carlo procedure in order to fit the experiments. This provides the optimum parameter values together with their statistical error bars. The approach is well suited for massively parallel computers, which allows us to do the data analysis within moderate computing times. The method is applied to flow near a hydrophilic surface, where the slip length is observed to be smaller than 10nm, and, within the limitations of the experiments and the model, indistinguishable from zero.

Diffusion and conformation of peptide-functionalized polyphenylene dendrimers studied by fluorescence correlation and 13C NMR spectroscopy.

We report on the combined use of fluorescence correlation spectroscopy (FCS) and 1H and 13C NMR spectroscopy to detect the size and type of peptide secondary structures in a series of poly-Z-L-lysine functionalized polyphenylene dendrimers bearing the fluorescent perylenediimide core in solution. In dilute solution, the size of the molecule as detected from FCS and 1H NMR diffusion measurements matches nicely. We show that FCS is a sensitive probe of the core size as well as of the change in the peptide secondary structure. However, FCS is less sensitive to functionality. A change in the peptide secondary conformation from beta-sheets to alpha-helices detected by 13C NMR spectroscopy gives rise to a steep increase in the hydrodynamic radii for number of residues n > or = 16. Nevertheless, helices are objects of low persistence.

Granisetron in repeated cycles of chemotherapy with platinum.

The aim of the present study was to assess the antiemetic efficacy of granisetron in repeated cycles of chemotherapy with platinum derivatives. The study included 50 patients (28 females, 22 males; aged 17-72, mean age 51 years). From 2 to 5 cycles of chemotherapy with cisplatin or carboplatin were performed. Granisetron was administered intravenously at a dose of 3 mg, 5 minutes before commencement of cytostatic chemotherapy. In case of 2 episodes of vomiting and severe nausea 2 additional doses of granisetron were given. Total control of emesis was achieved in 60% of patients after the first cycle of chemotherapy, and this percentage did not change significantly over the 5 cycles of chemotherapy. There were no differences in the antiemetic efficacy of granisetron in relation to patient sex up to cycle III, while in cycles IV and V a tendency towards less efficacy in females was observed. The adverse effects (headache, dizziness) were observed with the same frequency in the first 3 cycles of chemotherapy, while these were absent in cycles IV and V. Severe side effects were recorded only in cycle I, after that they were less expressed. In conclusion, granisetron is highly effective in prevention of emesis, induced by platinum derivatives and its efficacy is maintained over repeated cycles of chemotherapy. The toxicity of granisetron is mostly expressed in the first cycle, while after that it decreases significantly.

Cisplatin, vinblastine and bleocin in the treatment of disseminated testicular cancer.

Fifty-nine stage IV disseminated testicular cancer patients underwent 5 or more courses of cisplatin, vinblastine and bleocin (PVB) chemotherapy from August 1981 to July 1989. Tumour histology included 15 seminomas, 13 embryonal carcinomas, 13 teratocarcinomas and 18 mixed tumours. Thirty-four patients (58%) achieved complete remission with an average duration of 56+ months (range 3 to 113+), and 12 patients (20%) achieved partial remission with an average duration of 8.5 months (range 2 to 33). The overall response rate was 78%. Four patients achieved complete remission after adjunctive surgery. The best response was obtained in seminoma patients (73% complete remission). The 5-year survival is 88% for complete responders, 10% for partial responders, and 53% overall. The PVB combination has considerably improved the survival of disseminated testicular cancer patients, but the low survival rate in poor-risk patients necessitates more aggressive chemotherapy regimens.

Antitumor effect of combination of cyclophosphamide, adriamycin and platinum (CAP) versus cyclophosphamide, adriamycin and 5-fluorouracil (CAF) in metastatic breast cancer.

The aim of the present study was to evaluate the antitumor effect of two drug combinations in disseminated breast cancer. Eighty-one patients divided into two groups entered this nonrandomized study. Group 1 included 32 patients treated with CAP combination: Cyclophosphamide--200 mg/m2 on days 1, 3 and 5 + adriamycin--40 mg/m2 on day 1 + cisplatin--30 mg/m2 on days 1, 3 and 5. Group 2 included 49 patients treated with CAF combination: Cyclophosphamide--100 mg/m2 on days 1 to 14 + adriamycin--30 mg/m2 on days 1 and 8 + 5-fluorouracil--500 mg/m2 on days 1 and 8. All patients had at least 2 courses of chemotherapy. In Group 1 the remission rate was 50% (16 patients) including 3 complete (9%) and 13 partial remissions (41%). In Group 2 the remission rate was 39% (18 patients) with 8 complete (16%) and 10 partial remissions (23%). The analysis of duration of the remissions showed a tendency towards longer duration after treatment with CAP combination (25 versus 15 months for the complete remissions, and 14 versus 11 months for the partial remissions).