Keto-enol-based modification on piperlongumine to generate a potent Cu(II) ionophore that triggers redox imbalance and death of HepG2 cells.

Altered redox status including higher levels of copper in cancer cells than in normal cells inspired many researchers to develop copper ionophores targeting this status. We have recently found that flavon-3-ol (3-HF) works as a potent Cu(II) ionophore by virtue of its keto-enol moiety. To further emphasize the significance of this moiety for developing Cu(II) ionophores, we herein designed a ß-diketo analog of piperlongumine, PL-I, characterized by the presence of high proportion of the keto-enol form in dimethylsulfoxide and chloroform, and identified its keto-enol structure by NMR and theoretical calculations. Benefiting from deprotonation of its enolic hydroxyl group, this molecule is capable of facilitating the transport of Cu(II) through cellular membranes to disrupt redox homeostasis of human hepatoma HepG2 cells and trigger their death.

[Research on the photoelectric conversion efficiency of grating antireflective layer solar cells].

A numerical investigation of the effect of grating antireflective layer structure on the photoelectric conversion efficiency of solar cells was carried out by the finite-difference time-domain method. The influence of grating shape, height and the metal film thickness coated on grating surface on energy storage was analyzed in detail. It was found that the comparison between unoptimized and optimized surface grating structure on solar cells shows that the optimization of surface by grating significantly increases the energy storage capability and greatly improves the efficiency, especially of the photoelectric conversion efficiency and energy storage of the triangle grating. As the film thickness increases, energy storage effect increases, while as the film thickness is too thick, energy storage effect becomes lower and lower.

[Cardioprotective effects of propofol and midazolam in children with congenital heart diseases undergoing open heart surgery].

OBJECTIVE: To observe the cardioprotective effects of propofol and midazolam in children with congenital heart diseases undergoing open heart surgery. METHODS: Thirty-two children with cyanotic congenital heart diseases of ASA classes I - II were randomly divided into 2 equal groups: propofol combined with low dose fentanyl group (Group PF) and midazolam combined with low dose fentanyl group (Group MF). The changes of hemodynaics, ECG, SpO2, nasopharyngeal and rectal temperatures were monitored continuously. The time of tracheal extubation and ICU staying time were recorded. Venous blood samples were collected when the venous channel was opened (T(0)), 2 h after declamping of the aorta (T(4)), and 24 h after operation (T(5)) to detect the plasma cardiac troponin I (cTnI). Myocardium samples were collected 10 - 20 min after aorta cross-clamp (T(2)), and 10 - 20 min after declamping of the aorta (T(3)) to undergo immunohistochemistry to observe the expression of heme oxygenase-1 (HO-1). RESULTS: The tracheal time of Group GF was 14.17 h, significantly shorter than that of Group MF (23.65 h, P < 0.05), and the ICU staying time of Group GF was 30.17 h, significantly shorter than that of Group MF (49.47 h, P < 0.05). The plasma cTnI level at T(4) of Group GF was 97 ng/ml +/- 33 ng/ml, significantly higher than those at T(0) (0.17 ng/ml +/- 0.10 ng/ml, P < 0.01) and T(5) (23 ng/ml +/- 13 ng/ml, P < 0.01). The plasma cTnI level at T(4) of Group MF was138 ng/ml +/- 56 ng/ml, significantly higher than those at T(0) (0.62 ng/ml +/- 0.96 ng/ml, P < 0.01) and T(5) (24 ng/ml +/- 6 ng/ml, P < 0.01). And the plasma cTnI levels at T(5) of these 2 groups were both significantly higher than those at T(0) (both P < 0.01), however, there was no significant difference in the plasma cTnI level at any time point between these 2 groups. The grey values of HO-1 in cardiac muscle cells at T(2) of Groups GF and MF were 182.2 +/- 0.8 and 193.5 +/- 1.4, both significantly higher than those at T(3) (125.6 +/- 2.1 and 145.5 +/- 7.4 respectively, both P < 0.01), and the grey values of HO-1 in cardiac muscle cells at T(2) and T(3) of Group MF were both significantly higher than those of Group GF (both P < 0.05). CONCLUSION: Both propofol and midazolam have protective effects for the children with congenital heart diseases undergoing open heart surgery, and propofol is superior to midazolam in the cardioprotection.