Weak intrinsic charge transfer complexes: A new route for developing wide spectrum organic photovoltaic cells

Solar emission extends in the near IR and one of the main issues in designing organic solar cells resides in extending the response into the near IR. Here we show that this may be achieved by making intimate interpenetrated networks of C60 and Zn-phthalocyanine (Zn-Pc) in the solid. Various spectroscopic investigations of co-sublimated thin films of C60 and Zn-phthalocyanine give indeed ample evidence of the existence of a weak charge transfer (CT) state at 1.4 eV, which quenches the photoluminescence of both molecules. The films produced by co-sublimation undergo to a spinodal decomposition producing domains prevalently constituted by Zn-Pc in contact with domain prevalently of C60. The domains size depends on the deposition conditions (rate, stoichiometry, and substrate temperature) forming a percolating 3D network. The separation in different domains is confirmed by the observation of two overlapping peaks, in the resonant Raman spectrum, that correspond to the Ag(2) pinch mode (C=C double bond stretching) for pristine C60 and for a partially (~0.25e) doped one. This indicates that only those donor molecules at the grain boundary, which are in contact with C60, give rise to a renormalized new CT ground state. Photocurrent measurements of interpenetrated networks of C60 and Zn-Pc show a linear dependence with respect to the incident light as a consequence of direct absorption within the CT state. The CT state favors the charge separation between the two components, when it is inserted as interface in the organic photovoltaic p - n junction thus increasing the efficiency of the device

The Contribution of the Smectic-Nematic Interface to the Surface Energy

The contribution of the smectic-nematic interface to the surface energy of a nematic liquid crystal sample is analyzed. By means of a simple model it is shown that the surface energy depends on the thickness of the region over which the transition smectic-nematic takes place. For perfectly flat substrates this thickness is of the order of the correlation length entering in the transition. An estimate of this contribution shows that it is greater than the one arising from the nematic-substrate interaction. Moreover, it is also shown that the surface energy determined in this way presents a non-monotonic behavior with the temperature.Comment: 10 pages, revte

Realistic fluids as source for dynamically accreting black holes in a cosmological background

We show that a single imperfect fluid can be used as a source to obtain the generalized McVittie metric as an exact solution to Einstein's equations. The mass parameter in this metric varies with time thanks to a mechanism based on the presence of a temperature gradient. This fully dynamical solution is interpreted as an accreting black hole in an expanding universe if the metric asymptotes to Schwarzschild-de Sitter at temporal infinity. We present a simple but instructive example for the mass function and briefly discuss the structure of the apparent horizons and the past singularity.Comment: 5 pages, 2 figures. Updated references and minor changes to match the version accepted for publishing in PR

bcl-2, p53 and proliferating cell nuclear antigen expression is related to the degree of differentiation in thyroid carcinomas.

Thyroid carcinomas are heterogeneous in terms of histology, clinical presentation, treatment response and prognosis. Since bcl-2 and p53 gene alterations are frequently involved in both lymphoid and epithelial malignancies, we analysed the expression of bcl-2, p53 and proliferating cell nuclear antigen (PCNA) in a group of 134 patients with thyroid neoplasms. The same markers were evaluated in fetal and adult normal thyroids as well as in 40 benign lesions. The study was carried out by immunocytochemistry on archival material using antibodies against bcl-2 and p53 protein on tissue sections of 40 adenomas (As), 20 medullary carcinomas (MCs), 70 well-differentiated carcinomas (WDCs), 20 poorly differentiated carcinomas (PDCs) and 24 undifferentiated carcinomas (UCs). bcl-2 immunoreactivity was detected in 36 out of 40 (90%) As, 20 out of 20 (100%) MCs, 60 out of 70 (85.7%) WDCs, 20 out of 20 (100%) PDCs, and 8 out of 24 (33.3%) of UCs. p53 expression was present in 11.4% of WDCs, 5% of PDCs, 5% of MCs and 62.5% of UCs. By contrast, no p53 immunoreactivity was detected in 40 adenomas and in all the normal thyroid tissues studied. We observed a positive correlation between the expression of p53 and PCNA (r = 0.42; P = 0.035) in a group of UCs, but not in WDCs, PDCs and MCs. Neither p53 nor bcl-2 expression were correlated with clinicopathological parameters, such as age, sex, pTNM and survival. Our results suggest that in tumours of the follicular epithelium p53 and bcl-2 protein abnormalities are associated with more advanced carcinomas and especially with undifferentiated carcinomas, while they are only rarely altered in tumours of the parafollicular C cells

pre treatment egfr t790m subclones in lung adenocarcinoma harboring activating mutation of egfr a positive prognostic factor for survival

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P2X7 mRNA expression in non-small cell lung cancer: MicroRNA regulation and prognostic value

The human P2X7 receptor is significant and exhibits several functions in neoplasia. At present, little is known with regard to its regulation. P2X7 expression may be regulated post-transcriptionally and putative microRNA (miRNA) binding sites are considered to be involved. The aim of this study was to determine whether miRNAs (miR-21, let-7 g and miR-205) regulate P2X7 mRNA stability. In addition, the impact of P2X7 expression in patients with non-small cell lung cancer (NSCLC) was investigated. P2X7 mRNA and mature Let-7 g, miR-21, and miR-205 expression levels were quantified in 96 NSCLC cases using quantitative reverse transcription polymerase chain reaction. In all samples, epidermal growth factor receptor and K-Ras mutational analysis was also performed. Samples with low P2X7 expression were found to exhibit a higher fold change in miR-21 expression when compared with samples exhibiting high P2X7 expression. Significantly higher miR-21 expression was observed in the tumors of NSCLC patients with a K-Ras mutation when compared with patients who had K-Ras wild-type tumors (P=0.003). Additionally, to evaluate the association between P2X7 expression and prognosis in NSCLC patients, survival analysis was performed using the Kaplan-Meier method. A significant difference in the progression-free survival and overall survival in the NSCLC patients with high P2X7 expression was identified, when compared with that of patients with low expression (P=0.03 and P=0.02, respetively). Therefore, we hypothesized that high levels of miR-21 expression in NSCLC patients with K-Ras mutations may be regulated by a complex circuit, including P2X7 downregulation and together these processes may promote tumor progression

Apoptosis and proliferation in thyroid carcinoma: correlation with bcl-2 and p53 protein expression.

The aim of this study was to determine the apoptotic cell death in 92 thyroid carcinomas of different histotypes (42 papillary, PTC; 12 poorly differentiated, PDC: 21 undifferentiated, UC; and 17 medullary, MC) by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). Apoptotic index (Al, evaluated as a percentage of TUNEL-positive cells of neoplastic cells) was calculated in each tumour. The AI was very low in all subtypes of thyroid carcinoma, ranging from a median value of 0.2 in PTC to 1.4 in UC. The proliferative activity was determined by immunohistochemistry using monoclonal antibody, MIB-1. The percentage of proliferating cells was significantly different among the histotypes, increasing with tumour aggressiveness (from the mean value of 3.1 for PTC to 5.6 for PDC and 51.8 for UC). In addition, the ratio between proliferative activity and apoptosis was significantly higher in UC than in the other histotypes. The expression of bcl-2 and p53 protein (important in the modulation of cell death) was correlated (bcl-2, inverse correlation, r2 = 0.1, P = 0.04; p53, direct correlation, r2 = 0.11, P = 0.02) with apoptotic index in PTC

Primary tumor sidedness and benefit from FOLFOXIRI plus bevacizumab as initial therapy for metastatic colorectal cancer. Retrospective analysis of the TRIBE trial by GONO

Right-sided metastatic colorectal cancer (mCRC) patients have poor prognosis and achieve limited benefit from first-line doublets plus a targeted agent. In this unplanned analysis of the TRIBE study, we investigated the prognostic and predictive impact of primary tumor sidedness in mCRC patients and the differential impact of the intensification of the chemotherapy in subgroups defined according to both primary tumor sidedness and RAS and BRAF mutational status