Neutral liposomes (NLP) exhibit preferential localization in solid tumors based on the enhanced permeation and retention (EPR) effect. Cationic liposomes (CLP) have a propensity for localizing in newly formed tumor vessels and they have a potentially enhanced antitumor effect. However, an increased amount of cationic lipids in liposomes also induces aggregation through electrostatic interactions between the liposomes and the anionic species in the circulation, which results in a reduced EPR effect. Consequently, it is important to investigate the characteristics of liposomes with different surface potentials in vitro to achieve an optimal intratumoral distribution and antitumor effect in vivo. In this study, the authors evaluated the characteristics of doxorubicin (DOX)-loaded NLPs, CLPs, polyethylene glycol (PEG)-modified NLPs (NLP-PEG), and PEGylated CLPs (CLP-PEG) (ie, encapsulation efficacy, zeta potential, size, membrane fluidity, aggregation in serum, and uptake of liposomes into rat aortic endothelial cells (RAECs)) to further understand their influences on the pharmacokinetics, biodistribution, and antitumor therapy in vivo. The results showed that increased amounts of cationic lipids resulted in severe liposome aggregation in the presence of serum, yet it did not alter the membrane fluidity to a large extent. The uptake of liposomes into RAECs, visualized by confocal fluorescence microscopy, confirmed the rapid uptake of CLP by the endothelial cells compared with NLP. However, the pharmacokinetics, biodistribution and anticancer efficacies of these liposomes in vivo revealed that the CLP with highly positive surface potentials exhibited reduced circulation times and poor distribution in tumors. The NLP-PEG exhibited the highest anticancer efficacy; CLP-PEG, the second highest; and CLP with the most positive surface potential, the lowest. These phenomena were mostly due to the rapid aggregation in serum and subsequent accumulation in the lungs upon the intravenous injection of the CLP. Caution should be exercised when chemotherapeutic drugs are loaded into CLP for tumor therapy.
Coumarin is harmful to health but still used in cosmetics, tobacco, or illegally added into food as a spice in trace amounts so that it is exceedingly difficult to be determined accurately.
Hydrogen implantation was carried out on (001) germanium samples with doses of 3 × 1016 cm−2, 5 × 1016 cm−2 and 1 × 1017 cm−2 with 60 KeV, and germanium surface blistering phenomenon, raised by subsequent annealing in air in the temperature regions (200–250°C for 1 × 1017 cm−2 and 250–350°C for 3 × 1016 cm−2 and 5 × 1016 cm−2) for distinct durations, was studied. In Arrhenius plots that reflects the onset blistering time of annealing as a function of annealing temperature, there is a break point separated the each plot into two parts with distinct activation energies (∼2.1 eV and ∼0.6 eV) for 3 × 1016 cm−2 and 5 × 1016 cm−2 doses. The break point seems to be similar to other known materials but the opposite turning direction of the straight-line is completely different from other known materials because it is possible to derive from the diversity of defect-hydrogen complexes in germanium. On the other hand, the simple straight-line in Arrhenius plot is generated in the temperature range from 200–250°C with 1.57 eV activation energy as increasing H-implanted dose up to 1 × 1017 cm−2. The phenomenon of modifying blistering activation energy with H-implanted dose may be due to the mergence through the low and high activation energy because of competitive desorption of the defect-hydrogen complexes. The critical size of blisters to be exploded into craters increases with the enhancement of H-implanted dose and the rectangle-like periphery of the craters is obviously formed.
For traditional coherent effects, two separated identical point sources can be interfered with each other only when the optical path difference is integer number of wavelengths, leading to alternate dark and bright fringes for different optical path difference. For hundreds of years, such a perfect coherent condition seems insurmountable. However, in this paper, based on transformation optics, two separated in-phase identical point sources can induce perfect interference with each other without satisfying the traditional coherent condition. This shifting illusion media is realized by inductor-capacitor transmission line network. Theoretical analysis, numerical simulations and experimental results are performed to confirm such a kind of perfect coherent effect and it is found that the total radiation power of multiple elements system can be greatly enhanced. Our investigation may be applicable to National Ignition Facility (NIF), Inertial Confined Fusion (ICF) of China, LED lighting technology, terahertz communication, and so on.
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