Abstract:The aim of this study was to fabricate camptothecin/iron(III) oxide (CPT/Fe 2 O 3 )-loaded poly(D,L-lactide-co-glycolide) (PLGA) composite mats to modulate the CPT release and to improve the structural integrity and antitumor activity of the released drug. The CPT/Fe 2 O 3 -loaded PLGA ultrafine fibers were prepared for the first time by electrospinning a composite solution of CPT/Fe 2 O 3 and neat PLGA (4 weight percent). The physicochemical characterization of the electrospun composite mat was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, electron probe microanalysis, thermogravimetry, transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray diffraction pattern. The medicated composite fibers were evaluated for their cytotoxicity on C2C12 cells using Cell Counting Kit-8 assay (Sigma-Aldrich Corporation, St Louis, MO). The in vitro studies indicated a slow and prolonged release over a period of 96 hours with mild initial burst. Scanning electron microscopy, thermogravimetry, and X-ray diffraction studies confirmed the interaction of CPT/Fe 2 O 3 with the PLGA matrix and showed that the crystallinity of CPT decreased after loading. Incorporation of CPT in the polymer media affected both the morphology and the size of the CPT/Fe 2 O 3 -loaded PLGA composite fibers. Electron probe microanalysis and energy dispersive X-ray spectroscopy results confirmed welloriented composite ultrafine fibers with good incorporation of CPT/Fe 2 O 3 . The cytotoxicity results illustrate that the pristine PLGA did not exhibit noteworthy cytotoxicity; conversely, the CPT/Fe 2 O 3 composite fibers inhibited C2C12 cells significantly. Thus, the current work demonstrates that the CPT/Fe 2 O 3 -loaded PLGA composite fibers represent a promising chemotherapeutic system for enhancing anticancer drug efficacy and selectively targeting cancer cells in order to treat diverse cancers.
Mn₂O₃ nanowires with diameter ~70 nm were synthesized by a simple hydrothermal method using Mn(II) nitrate as precursor. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy techniques were employed to study structural features and chemical composition of the synthesized nanowires. A biological evaluation of the antimicrobial activity and cytotoxicity of Mn₂O₃ nanowires was carried out using Escherichia coli and mouse myoblast C₂C₁₂ cells as model organism and cell lines, respectively. The antibacterial activity and the acting mechanism of Mn₂O₃ nanowires were investigated by using growth inhibition studies and analyzing the morphology of the bacterial cells following the treatment with nanowires. These results suggest that the pH is critical factor affecting the morphology and production of the Mn₂O₃ nanowires. Method developed in the present study provided optimum production of Mn₂O₃ nanowires at pH ~ 9. The Mn₂O₃ nanowires showed significant antibacterial activity against the E. coli strain, and the lowest concentration of Mn₂O₃ nanowires solution inhibiting the growth of E. coli was found to be 12.5 μg/ml. TEM analysis demonstrated that the exposure of the selected microbial strains to the nanowires led to disruption of the cell membranes and leakage of the internal contents. Furthermore, the cytotoxicity results showed that the inhibition of C₂C₁₂ increases with the increase in concentration of Mn₂O₃ nanowires. Our results for the first time highlight the cytotoxic and bactericidal potential of Mn₂O₃ nanowires which can be utilized for various biomedical applications.
The contents of multi-elements in whole blood from 115 patients with 7 different types of acute leukemia and 38 well matched healthy controls have been determined by means of proton induced X-ray emission (PIXE). The number of available analyzed elements was as many as 11, mainly due to the use of a 100 um thick Cr funny foi1 as an absorber. The contents of elements Cu, Ca, S, P, Si and the ratio of Cu to Zn (Cu/Zn) were higher and those of elements Zn, K, Fe, Al and Rb were lower with high significant differences (P<0. 01) in acute leukemia patients than in norma1 controls. The results indicate that the contents of Cu, Zn, and the ratio Cu/Zn are useful indices of disease activity. The elements of Al and Rb may play important roles in acute leukemia etiology,
Partial discharge (PD) in gas insulated switchgear (GIS) is one of important factors causing accidents. The PD can lead to the decomposition of SF6, generating different gas components. To detect and analyze the decomposed characteristic components of SF6 under PD is significant for fault diagnosis of GIS. However, how to detect the characteristic components from mixed gas components is a main puzzler. In this paper, the molecular dynamics simulation software of MS is used to calculate accurately the process of single-wall carbon nannobutes modified by hydroxide radical (SWNT-OH) adsorbing the main components of SF6 decomposed under PD. The main components contain SOF2, SO2F2, SO2 and CF4. By analyzing the frontier orbital of gas molecules and SWNT-OH, as well as adsorption energy, charge transfer and the electronic density of states in the adsorption process, and the values of energy gap after SWNT-OH adsorbing the gas molecules, the sensitivity and the selectivity of SWNT-OH on gas molecules are evaluated and the theoretical basis on whether the SWNTOH can be prepared as gas sensors to detect the components of SF6 decomposed under PD is presented.
Design procedure for longitudinal slot arrays fed by air-filled rectangular waveguide including mutual coupling has been discussed and studied in many papers, and widely applied.Due tocomplexity of internal field, it is difficult toemploy the same method on slot arrays fed by ridge waveguide. In this paper, a newdesign procedureis introduced for slot arrays fed by single-ridge waveguide, which simplified the procedure of the previous one.A array wasconstructed and tested, and the result validates the theory.
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