Nonlinear analysis of EEG signals at different mental states

BACKGROUND: The EEG (Electroencephalogram) is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer can not directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in diagnostics. This work discusses the effect on the EEG signal due to music and reflexological stimulation. METHODS: In this work, nonlinear parameters like Correlation Dimension (CD), Largest Lyapunov Exponent (LLE), Hurst Exponent (H) and Approximate Entropy (ApEn) are evaluated from the EEG signals under different mental states. RESULTS: The results obtained show that EEG to become less complex relative to the normal state with a confidence level of more than 85% due to stimulation. CONCLUSIONS: It is found that the measures are significantly lower when the subjects are under sound or reflexologic stimulation as compared to the normal state. The dimension increases with the degree of the cognitive activity. This suggests that when the subjects are under sound or reflexologic stimuli, the number of parallel functional processes active in the brain is less and the brain goes to a more relaxed stat

Effect of reflexology on EEG - A nonlinear approach

10.1142/S0192415X04002272American Journal of Chinese Medicine324641-650AJCM

Functionalized gold nanoparticles for topical delivery of methotrexate for the possible treatment of psoriasis

Gold nanoparticles (AuNPs) represent an effective choice for topical drug delivery systems thanks to their small size, general non-toxicity, ease of functionalization and high surface to volume ratio. Even if systemic, methotrexate still plays an important role in psoriasis treatment: its topical use shows insufficient percutaneus penetration owing to limited passive diffusion, high molecular weight and dissociation at physiological pH. The aim of our study was to design a new drug delivery nanocarrier for Methotrexate and to improve its solubility, stability and biodistribution. AuNPs were on purpose prepared with a hydrophilic stabilizing layer, in order to improve the colloidal stability in water. Water-soluble gold nanoparticles functionalized by sodium 3-mercapto-1-propansulfonate (Au-3MPS) were prepared and loaded with methotrexate (MTX). The loading efficiency of MTX on Au-3MPS was assessed in the range 70-80%, with a fast release (80% in one hour). The release was studied up to 24 h reaching the value of 95%. The Au-3MPS@MTX conjugate was fully characterized by spectroscopic techniques (UV-vis, FTIR) and DLS. Preliminary toxicity tests in the presence of keratinocytes monolayers allowed to assess that the used Au-3MPS are not toxic. The conjugate was then topically used on C57BL/6 mouse normal skin in order to trace the absorption behavior. STEM images clearly revealed the distribution of gold nanoparticles inside the cells. In vitro studies showed that Methotrexate conjugated with Au-3MPS is much more efficient than Methotrexate alone. Moreover, DL50, based on MTT analysis, is 20 folds reduced at 48 h, by the presence of nanoparticles conjugation. UV-vis spectra for in vivo tracing of the conjugate on bare mouse skin after 24 h of application, show increased delivery of Methotrexate in the epidermis and dermis using Au-3MPS@MTX conjugate, compared to MTX alone. Moreover we observed absence of the Au-3MPS in the dermis and in the epidermis, suggesting that these layers of the skin do not retain the nanoparticles. Based on our data, we found that the novel Au-3MPS@MTX conjugate is an effective non-toxic carrier for the satisfactory percutaneous absorption of Methotrexate and could help in possible topical treatment of psoriasis

Gold Nanoparticles-enabled Efficient Dual Delivery of Anticancer Therapeutics to HeLa Cells

Abstract Colloidal gold nanoparticles (AuNPs) are of interest as non-toxic carriers for drug delivery owing to their advanced properties, such as extensive surface-to-volume ratio and possibilities for tailoring their charge, hydrophilicity and functionality through surface chemistries. To date, various biocompatible polymers have been used for surface decoration of AuNPs to enhance their stability, payloads capacity and cellular uptake. This study describes a facile one-step method to synthesize stable AuNPs loaded with combination of two anticancer therapeutics, -bleomycin and doxorubicin. Anticancer activities, cytotoxicity, uptake and intracellular localization of the AuNPs were demonstrated in HeLa cells. We show that the therapeutic efficacy of the nanohybrid drug was strongly enhanced by the active targeting by the nanoscale delivery system to HeLa cells with a significant decrease of the half-maximal effective drug concentration, through blockage of HeLa cancer cell cycle. These results provide rationale for further progress of AuNPs-assisted combination chemotherapy using two drugs at optimized effective concentrations which act via different mechanisms thus decreasing possibilities of development of the cancer drug resistance, reduction of systemic drug toxicity and improvement of outcomes of chemotherapy