Front-side illuminated CdS/CdSe quantum dots co-sensitized solar cells based on TiO2 nanotube arrays.

We fabricated a front-side illuminated CdS/CdSe quantum dots co-sensitized solar cell based on TiO(2) nanotube arrays. The freestanding TiO(2) nanotube arrays were first detached from anodic oxidized Ti foils and then transferred to the fluorine-doped tin oxide to form photoanodes. An opaque Cu(2)S with high electrochemical activity was used as the counter electrode. A photovoltaic conversion efficiency as high as 3.01% under one sun illumination has been achieved after optimizing the deposition time of CdSe quantum dots and the length of the TiO(2) nanotube arrays. It is observed that the power conversion efficiency of quantum dots sensitized solar cells from the front-side illumination mode (3.01%) is much higher than that of the back-side illumination mode (1.32%) owing to the poor catalytic activity of Pt to polysulfide electrolytes and light absorption by the electrolytes for the latter.

Melamine induces sperm DNA damage and abnormality, but not genetic toxicity.

Melamine is a category III carcinogen. However, its illegal addition to milk and other protein products has led to the pet melamine poisoning in USA and infant renal calculus cases in China. Its long-term toxicity is not clear and needs to be investigated urgently to appease the public panic. In this study, the effects of melamine on mutagenesis in prokaryotes and eukaryotes were tested by Ames test, in vitro mammalian chromosome aberration test, mouse micronucleus test and sperm abnormality test; the effects of melamine on DNA damage in sperm cells were observed by single cell gel electrophoresis, and the effects on malignant transformation were examined by malignant transformation experiment of normal human liver cell line L02. The results show that melamine has no mutagenic function in prokaryotes and eukaryotes in vitro and in vivo, and does not induce malignant cell transformation after long-term exposure. However, it has ability to increase sperm abnormality rate and DNA damage.

[Effects of indole-3-carbinol on the outcome of tumor and the changes of anti-oxidative system in null mice grafted with nasopharyngeal carcinoma].

OBJECTIVE: To observe the effects of indole-3-carbinol (I3C) on the outcome of the tumor as well as the changes of the anti-oxidative system in null mice grafted with nasopharyngeal carcinoma. METHODS: 48 BALB/c null mice were divided by means of random number table into control group (0.5% sodium carboxyl methyl cellulose), low dosage (0.02 g/kg), middle dosage (0.1 g/kg) and high dosage (0.5 g/kg) of I3C. The mice were administered with different solutions by gavage for 10 days before CNE1 cells were inoculated subcutaneously into the back (near the armpit) of the nude mice, then the solutions were continually administered by gavage. The tumor volume was measured and the tumor inhibitory rate was calculated. The level of malondialdehyde (MDA), the activity of superoxide dismutases (SOD), the activity of glutathione peroxidase (GSHPx) and the expression of cleaved caspase-3 were determined on the 31th day of the study. RESULTS: I3C could reduce the tumor volume [the tumor volumes of the control group, the middle dosage group and the high dosage group were (4.13 +/- 0.53) x 10(-6) m(3), (3.14 +/- 0.71) x 10(-6) m(3), (2.72 +/- 0.29) x 10(-6) m(3)], as compared with the control, the shrinkage of tumor volume of the middle dosage group and the high dosage group were significant (the t valued at 0.990 and 1.510, P < 0.01). The tumor inhibitory rates of 3 groups were 3.8%, 20.5% and 34.9%, respectively. The contents of MDA in the tumor tissue tended to decrease [the values of control group, the low dosage group, the middle dosage group and the high dosage group were (31.29 +/- 2.51) x 10(-6) mol/L, (30.12 +/- 2.37) x 10(-6) mol/L, (23.32 +/- 1.93) x 10(-6) mol/L, (16.45 +/- 1.43) x 10(-6) mol/L] (F = 98.752, P < 0.01), and that of the high and the middle dosage group could obviously be reduced (t = 8.970, 14.840, P < 0.01) as compared with the control. The activity of SOD seemed to be elevated according to the increase of I3C dosage [the values were (387.24 +/- 23.16) x 10(3) U/L, (399.37 +/- 34.45) x 10(3) U/L, (431.63 +/- 31.24) x 10(3) U/L, (476.45 +/- 44.67) x 10(3) U/L] (F = 53.444, P < 0.01). When compared with the control, the SOD activity of the middle and the high dosage group be obviously increased (t = 44.390, 89.210, P < 0.01). I3C could also elevate the GSHPx activity [the GSHPx values of the four groups were (226.98 +/- 18.35) x 10(3) U/L, (234.65 +/- 15.59) x 10(3) U/L, (247.72 +/- 22.73) x 10(3) U/L, (300.37 +/- 26.02) x 10(3) U/L] (F = 25.916, P < 0.01). The GSHPx of the high dosage group was enhanced remarkable (t = 73.390, P < 0.01) as compared with the control. The expression of cleaved caspase-3 (relative molecular weight = 19 000 000) seemed to be elevated according to the increase of I3C dosage and the relative expression levels of which were 0.87 +/- 0.01, 0.97 +/- 0.01, 1.02 +/- 0.06 and 1.14 +/- 0.02 (F = 39.864, P < 0.01). When compared with the control, the elevation of this kind of cleaved caspase-3 was considered statistical significant (the t values were 0.100, 0.086 and 0.303, respectively, P < 0.05). When I3C dosage increased, the expression of cleaved caspase-3 (relative molecular weight = 17 000 000) seemed to increased too [the relative expression levels of which were 0.00 +/- 0.00, 0.05 +/- 0.02, 0.11 +/- 0.02, 0.20 +/- 0.02 (F = 56.629, P < 0.01)], and the increase of this kind of cleaved caspase-3 was esteemed significantly as compared with those of the control (the t valued at 0.046, 0.103 and 0.193, respectively, P < 0.05). Linear correlate analysis showed that the correlation coefficients between the shrinkage of tumor volume and the expression of the two kinds of cleaved caspase-3 protein was -0.732 (t = 3.404, P < 0.01) and -0.901 (t = 6.642, P < 0.01). CONCLUSION: I3C could reduce the growth of tumor, the mechanism underlie it could be related to the decrease of the content of MDA as well as the elevated levels of SOD, GSHPx, and perhaps could be related to the apoptosis transduced by cleaved caspase-3.

Adsorption of phenolic compounds from aqueous solutions by aminated hypercrosslinked polymers.

Two novel polymers (NJ-1 and NJ-2) were synthesized by chemically modified a hypercrosslinked polymer NJ-0 with dimethylamine and trimethylamine, respectively. The comparison of the adsorption properties of the three polymers toward phenol, resorcin and phloroglucin was made. The study focused on the static equilibrium adsorption behaviors and the adsorption thermodynamics. Freundlich equation was found to fit the adsorption results well. The effect of amino groups introduced onto the surface of the resin and the structure of phenolic compounds on the adsorption were also studied. The hydrogen-bonding interaction and electrostatic interaction could happen between the amino groups and the adsorbates. The adsorption impetus increased as quantity of hydroxyl groups increased, but the adsorption capacity decreased due to the drop of the matching degree of the aperture of resins and the diameter of adsorbate molecules.