Enhanced cellular uptake and cytotoxicity of folate decorated doxorubicin loaded PLA-TPGS nanoparticles

Doxorubicin (DOX) is one of the most effective anticancer drugs for treating many types of cancer. However, the clinical applications of DOX were hindered because of serious side-effects resulting from the unselective delivery to cancer cell including congestive heart failure, chronic cardiomyopathy and drug resistance. Recently, it has been demonstrated that loading anti-cancer drugs onto drug delivery nanosystems helps to maximize therapeutic efficiency and minimize unwanted side-effects via passive and active targeting mechanisms. In this study we prepared folate decorated DOX loaded PLA-TPGS nanoparticles with the aim of improving the potential as well as reducing the side-effects of DOX. Characteristics of nanoparticles were investigated by field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS) method and Fourier transform infrared spectroscopy (FTIR). Anticancer activity of the nanoparticles was evaluated through cytotoxicity and cellular uptake assays on HeLa and HT29 cancer cell lines. The results showed that prepared drug delivery system had size around 100 nm and exhibited higher cytotoxicity and cellular uptake on both tested HeLa and HT29 cells
http://repository.vnu.edu.vn/handle/VNU_123/34087

Tyrosinase inhibitory activity of flavonoids from Artocarpus heterophyllous

Tyrosinase is an oxidoreductase that is very important in medicine and cosmetics because the excessive production of melanin causes hyperpigmentation. The development of novel, effective tyrosinase inhibitors has long been pursued. In preliminary tests, we found that an extract of the wood of Artocarpus heterophyllous (AH) potently inhibited tyrosinase activity. Results: Two new flavonoids, artocaepin E (1) and artocaepin F (2), were isolated from the wood of AH, together with norartocarpetin (3), artocarpanone (4), liquiritigenin (5), steppogenin (6), and dihydromorin (7). Their structures were elucidated using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry. The absolute configuration of 2 was determined from the circular dichroism (CD) spectrum. Artocarpanone (4) had the most potent tyrosinase inhibitory effect, with an IC50 of 2.0 ± 0.1 μM, followed by artocaepin E (1) and steppogenin (6), with IC50 values of 6.7 ± 0.8 and 7.5 ± 0.5 μM, respectively. A kinetic investigation indicated that 1 showed competitive inhibition, with an inhibition constant (K i) of 6.23 μM. Conclusions: These results demonstrate that extracts of the wood of AH and its phytochemical constituents are potential sources for skin-whitening agents. Graphical abstract Artocarmin E (1) and artocarmin F (2) were isolated from the wood of Artocarpus heterophyllous. Their structures were elucidated using nuclear magnetic resonance analysis and mass spectrometric methods
http://repository.vnu.edu.vn/handle/VNU_123/34089

The Index-based optical spatial modulation scheme in optical MIMO

Optical Multi-Input and Multi-Output (O-MIMO) is considered as an effective solution in order to achieve high performance for Visible Light Communication (VLC) systems. However, O-MIMO systems are faced with the impact of Inter- Channel Interference (ICI) which results in system performance decrease. In this paper, a novel Index-based Optical Spatial Modulation (IOSM) is proposed to remove ICI and increase spectrum efficiency for indoor VLC systems applying O-MIMO. In our proposed scheme, the signals are DC biased for intensity modulation and direct detection (IM/DD) and a Maximumlikelihood (ML) decoder decision to maximize the signal-To-noise ratio (SNR) at the receiver. Computer simulation results show that the proposed scheme outperforms previously proposed spatial modulation schemes in O-MIMO systems.
http://repository.vnu.edu.vn/handle/VNU_123/34090

The nonlinear stability of axisymmetric functionally graded material annular spherical shells under thermo-mechanical load

The authors of this article investigate the nonlinear stability of axisymmetric functionally graded annular spherical shells with temperature-dependent material properties subjected to thermo-mechanical loads and resting on elastic foundations. Equilibrium and compatibility equations are derived by using the classical thin shell theory in terms of the shell deflection and the stress function. Approximate analytical solutions are assumed to satisfy simply supported boundary conditions and Galerkin method is applied to obtain the closed-form of load-deflection paths. An analysis is carried out to show the effects of material and geometrical properties and combination of loads on the stability of the shells.
http://repository.vnu.edu.vn/handle/VNU_123/34091

The Perceived Value of Passive Animal Health Surveillance The Case of Highly Pathogenic Avian Influenza in Vietnam

Economic evaluations are critical for the assessment of the efficiency and sustainability of animal health surveillance systems and the improvement of their efficiency. Methods identifying and quantifying costs and benefits incurred by public and private actors of passive surveillance systems (i.e. actors of veterinary authorities and private actors who may report clinical signs) are needed. This study presents the evaluation of perceived costs and benefits of highly pathogenic avian influenza (HPAI) passive surveillance in Vietnam. Surveys based on participatory epidemiology methods were conducted in three provinces in Vietnam to collect data on costs and benefits resulting from the reporting of HPAI suspicions to veterinary authorities. A quantitative tool based on stated preference methods and participatory techniques was developed and applied to assess the non-monetary costs and benefits. The study showed that poultry farmers are facing several options regarding the management of HPAI suspicions, besides reporting the following: treatment, sale or destruction of animals. The option of reporting was associated with uncertain outcome and transaction costs. Besides, actors anticipated the release of health information to cause a drop of markets prices. This cost was relevant at all levels, including farmers, veterinary authorities and private actors of the upstream sector (feed, chicks and medicine supply). One benefit associated with passive surveillance was the intervention of public services to clean farms and the environment to limit the disease spread. Private actors of the poultry sector valued information on HPAI suspicions (perceived as a non-monetary benefit) which was mainly obtained from other private actors and media.
http://repository.vnu.edu.vn/handle/VNU_123/34092