RESUMO
Feature space transformation techniques have been widely studied for dimensionality reduction in vector-based feature space. However, these techniques are inapplicable to sequence data because the features in the same sequence are not independent. In this paper, we propose a method called max-min inter-sequence distance analysis (MMSDA) to transform features in sequences into a low-dimensional subspace such that different sequence classes are holistically separated. To utilize the temporal dependencies, MMSDA first aligns features in sequences from the same class to an adapted number of temporal states, and then, constructs the sequence class separability based on the statistics of these ordered states. To learn the transformation, MMSDA formulates the objective of maximizing the minimal pairwise separability in the latent subspace as a semi-definite programming problem and provides a new tractable and effective solution with theoretical proofs by constraints unfolding and pruning, convex relaxation, and within-class scatter compression. Extensive experiments on different tasks have demonstrated the effectiveness of MMSDA.
RESUMO
Objective To prepare quercetin ( QT )-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate ( PLGA-TPGS) nanoparticles ( QPTN) and QT-loaded polylactic-co-glycolic acid ( PLGA) nanoparticles ( QPN) by using QT as model drug and PLGA-TPGS or PLGA as carrier materials, and to investigate the quality of the two nanoparticles. Methods QPTN and QPN were prepared by using the ultrasonic emulsification-solvent evaporation method, and their surface morphology,size and surface charge were detected by using a transmission electron microscope ( TEM) and a Nano ZS90 light scattering and laser Doppler anemometry, respectively. Drug loading ( DL) , entrapment efficiency ( EE) and in vitro drug release of QT in the two nanoparticles were determined by using a reverse phase-high performance liquid chromatography (RP-HPLC) on Hypersil C18 column (4.6 mm×250 mm, 5 μm) with methanol and 0.03% phosphoric acid (3︰2) as mobile phase, and the detective wavelength was 370 nm. Results TEM images exhibited that two nanoparticles were all spherical and regular. The average sizes of QPTN and QPN were (155.4±2.7) nm and (363.8±3.2) nm, while DL and EE of QPTN were approximately (21.6±2.8)%, (93.7±2.9)% (n=6), and DL and EE of QPN were approximately (15.0±1.5)%, (64.6± 1.6)% (n=6), respectively. Both of nanoparticles exhibited sustained release, and the cumulative QT release of QPTN and QPN reached (85.8±2.8)% and (68.6±1.4)% (n=6) at day 30, respectively, with a significant difference between them (P<0.05) . Conclusion QPTN gets smaller size, higher DL and EE, and exhibits sustained release, and the in vitro cumulative QT release is faster and more complete than QPN relatively.
RESUMO
Objective To prepare quercetin ( QT )-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate ( PLGA-TPGS) nanoparticles ( QPTN) and QT-loaded polylactic-co-glycolic acid ( PLGA) nanoparticles ( QPN) by using QT as model drug and PLGA-TPGS or PLGA as carrier materials, and to investigate the quality of the two nanoparticles. Methods QPTN and QPN were prepared by using the ultrasonic emulsification-solvent evaporation method, and their surface morphology,size and surface charge were detected by using a transmission electron microscope ( TEM) and a Nano ZS90 light scattering and laser Doppler anemometry, respectively. Drug loading ( DL) , entrapment efficiency ( EE) and in vitro drug release of QT in the two nanoparticles were determined by using a reverse phase-high performance liquid chromatography (RP-HPLC) on Hypersil C18 column (4.6 mm×250 mm, 5 μm) with methanol and 0.03% phosphoric acid (3︰2) as mobile phase, and the detective wavelength was 370 nm. Results TEM images exhibited that two nanoparticles were all spherical and regular. The average sizes of QPTN and QPN were (155.4±2.7) nm and (363.8±3.2) nm, while DL and EE of QPTN were approximately (21.6±2.8)%, (93.7±2.9)% (n=6), and DL and EE of QPN were approximately (15.0±1.5)%, (64.6± 1.6)% (n=6), respectively. Both of nanoparticles exhibited sustained release, and the cumulative QT release of QPTN and QPN reached (85.8±2.8)% and (68.6±1.4)% (n=6) at day 30, respectively, with a significant difference between them (P<0.05) . Conclusion QPTN gets smaller size, higher DL and EE, and exhibits sustained release, and the in vitro cumulative QT release is faster and more complete than QPN relatively.