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Background: Inflammatory bowel disease (IBD; mainly ulcerative colitis and Crohn's disease) is associated with the development of colorectal cancer (CRC) referred to as colitis-associated colorectal cancer (CAC). In inflammatory flares of IBD, the production of luminal nitric oxide (NO) increases due to the increased inducible nitric oxide synthase (iNOS) activity in inflamed tissue. It is believed that iNOS parallels pro-inflammatory interleukin-1β (IL-1β). How these biomarkers relate to CAC pathogenesis or survival is unknown. Aim: The primary aim of this study was to investigate iNOS and IL-1β immunoreactivity in CAC tumors in comparison with CRC and normal colonic mucosa, and the secondary aim was to determine if immunoreactivity correlates with 5-year survival of CAC. Methods: Immunohistochemistry was performed on tissue sections as follows: CAC (n = 59); sporadic CRC (sCRC) (n = 12); colonic mucosa >2 cm outside sCRC margin (normal mucosa) (n = 22); paracancerous IBD (pIBD) (n = 12). The expression of iNOS and IL-1β was quantified separately for epithelium and stroma. Data were evaluated using the Mann-Whitney U-test and the log-rank test for 5-year Kaplan-Meier survival curves. Results were compared with online mRNA databases. Results: Immunoreactivity occurred predominantly in epithelial cells and to lesser extent in stroma. Compared with normal mucosa, immunoreactivity for iNOS (P < 0.01) and IL-1β (P < 0.005) was higher in CAC epithelium. In CAC stroma, iNOS immunoreactivity was lower than normal mucosa (P < 0.001), whereas IL-1β was higher (P < 0.05). Immunoreactivity differences of iNOS or IL-1β among CAC patients failed to correlate with 5-year survival. These findings were supported by online mRNA databases. Conclusion: Consistent with high NO production in IBD, there is more iNOS in CAC epithelium, albeit not in stroma. This immunoreactivity difference exists for IL-1β in both epithelium and stroma. The intervention of arginine or iNOS activity for CAC chemotherapy is not straightforward. [ABSTRACT FROM AUTHOR]

A comparative study with focusing on carrier recombination properties in Cu2ZnSn(S,Se)4 (CZTSSe) and the CuInGaSe2 (CIGS) solar cells has been carried out. For this purpose, electroluminescence (EL) and also bias-dependent time resolved photoluminescence (TRPL) using femtosecond (fs) laser source were performed. For the similar forward current density, the EL-intensity of the CZTSSe sample was obtained significantly lower than that of the CIGS sample. Primarily, it can be attributed to the existence of excess amount of non-radiative recombination center in the CZTSSe, and/or CZTSSe/CdS interface comparing to that of CIGS sample. In case of CIGS sample, TRPL decay time was found to increase with the application of forward-bias. This can be attributed to the reduced charge separation rate resulting from the reduced electric-field at the junction. However, in CZTSSe sample, TRPL decay time has been found almost independent under the forward and reverse-bias conditions. This phenomenon indicates that the charge recombination rate strongly dominates over the charge separation rate across the junction of the CZTSSe sample. Finally, temperature dependent VOC suggests that interface related recombination in the CZTSSe solar cell structure might be one of the major factors that affect EL-intensity and also, TRPL decay curves. [ABSTRACT FROM AUTHOR]

Deep-level defects were investigated in Cu2ZnSn(S,Se)4 and Cu2ZnSnS4 thin-films using transient photocapacitance (TPC) spectroscopy. A deep-defect, OH1 centered around 1.0 eV above the valanceband (EV) of Cu2ZnSnS4 has been identified at room temperature (RT). However, OH1-defect could be identified in Cu2ZnSn(S,Se)4 at low temperature only. Absence of OH1-defect in Cu2ZnSn(S,Se)4 at RT explains its better performance comparing to Cu2ZnSnS4 solar-cell. A comparative study of the TPC spectra of the Cu(In,Ga)Se2 solar-cells was performed. Low intensity of defect-signal together with lower broadening of exponential band-tail in the TPC spectra were attributed to superior performance of Cu(In,Ga)Se2 solar-cells comparing to Cu2ZnSn(S,Se) counterpart. [ABSTRACT FROM AUTHOR]