Isolation and Purification of Sesquiterpene Lactones from Ixeris sonchifolia (Bunge) Hance by High-Speed Counter- Current Chromatography and Semi-Preparative High Performance Liquid Chromatography

Purpose: To isolate and purify sesquiterpene lactones from Ixeris sonchifolia (Bunge) Hance by highspeed counter-current chromatography (HSCCC).Methods: I. sonchifolia was extracted with water and then loaded on a glass column (10 ~ 1500 cm containing 3000g D101 macroporous resin) where various concentrations of aqueous ethanol (0, 10, 30, 50, and 95 %) were used to elute the column successively. The 50 % ethanol fraction was  purified by HSCCC using a solvent system comprised of ethyl acetate: n-butanol: methanol: water (4: 6: 1: 20, v/v), and semi-preparative high performance liquid chromatography (HPLC). The chemical structures of thecomponents obtained were further confirmed by high-resolution mass spectroscopy (MS) and nuclear magnetic resonance spectroscopy (NMR).Results: Three compounds, including ixerin Z1 (0.7 mg), ixerin Z (11.4 mg), and 11, 13α-dihydroixerin Z (8.2 mg), with purity of 96.2, 98.2, and 98.4 %, respectively, were obtained from 200 mg each of the 50 % ethanol fraction.Conclusion: HSCCC is a rapid and effective method for isolating and purifying sesquiterpene lactones from I. sonchifolia.Keywords: Sesquiterpene lactones, High-speed counter-current chromatography, Ixeris sonchifolia, Ixerin, 13α-Dihydroixeri

Impact of the solar wind dynamic pressure on the field‐aligned currents in the magnetotail: Cluster observation

We statistically investigate the influence of the solar wind dynamic pressure (SW Pdyn) on the field-aligned currents (FACs) in the magnetotail with 1492 FAC cases from July to October in 2001 and 2004, which covers 74 Cluster crossings of the plasma sheet boundary layer (PSBL) in both storm time and non-storm time. The FAC density in the magnetotail is derived from the magnetic field data with the four-point measurement of Cluster, and the SW Pdyn is taken from ACE data. The results indicate the FAC density becomes stronger with increasing SW Pdyn. The statistics show that the FAC occurrence increased monotonically with SW Pdyn in the three levels (Weak: SW Pdyn5 nPa). The FAC density increased with increasing SW Pdyn, while its footprint (invariant latitude, ILAT) in the polar region decreased with increasing SW Pdyn. The response of the FAC to SW Pdyn in the magnetotail had a north-south hemispheric asymmetry. The FAC density had a better correlation with SW Pdyn in the Northern hemisphere, while the footprint had a better correlation with SW Pdyn in the Southern hemisphere. Possible underlying mechanisms for our results are analyzed and discussed. However, it requires more observations and simulation studies to find out the mechanism of north-south asymmetry

Cyclodextrin-PEI-Tat Polymer as a Vector for Plasmid DNA Delivery to Placenta Mesenchymal Stem Cells

This study aims to modify a cyclodextrin-PEI-based polymer, PEI-β-CyD, with the TAT peptide for plasmid DNA delivery to placenta mesenchymal stem cells (PMSCs). By using the disulfide exchange between the SPDP-activated PEI-β-CyD and TAT peptide, the TAT-PEI-β-CyD polymer was fabricated and the success of this was confirmed by the presence of characteristic peaks for PEI (at δ 2.8-3.2 ppm), CyD (at δ 5.2, 3.8-4.0 and 3.4-3. 6 ppm) and TAT (at δ 1.6-1.9 and 6.8-7.2 ppm) in the 1H NMR spectrum of TAT-PEI-β-CyD. The polymer-plasmid-DNA polyplex could condense DNA at an N/P ratio of 7.0-8.0, and form nanoparticles with the size of 150.6±5.6 nm at its optimal N/P ratio (20/1). By examining the transfection efficiency and cytotoxicity of TAT-PEI-β-CyD, conjugation of the TAT peptide onto PEI-β-CyD was demonstrated to improve the transfection efficiency of PEI-β-CyD in PMSCs after 48 and 96 hours of post-transfection incubation. The viability of PEI-β-CyD-treated PMSCs was shown to be over 80% after 5 h of treatment and 24 h of post-treatment incubation. In summary, this study showed that the TAT-PEI-β-CyD polymer as a vector for plasmid DNA delivery to PMSCs and other cells warrants further investigations. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Sizing optimization of trapezoidal corrugated roof sheeting, supporting solar panels, under wind loading

The dimensions of trapezoidal roof sheeting supporting solar panels are optimized so that a minimum amount of steel is required for a specific range of wind loads. Sheets of different grades and different thicknesses along with different ranges of wind speeds are considered. In order to simulate the behavior of the corrugated sheets analysis is carried out for two limit states: strength and serviceability. For both limit states, the objective is to minimize the weight per unit area of the panels. First, optimum cross-section is obtained to meet the strength conditions. Then the deflection is controlled for serviceability. The optimum dimensions for each steel grade and loading condition are determined. The optimization problem is formulated as a multi-objective problem that aims to minimize the section\u27s weight and maximize the section elastic modulus under the wind loading condition. A graph theory based approach is presented for the sizing optimization, employing an applied graph theory approach for the multi-objective all pairs shortest path problem. The proposed methodology addresses the sizing optimization problem to determine the geometry of the thin-walled cold-formed steel cross-sections that satisfy the design topological constraints

On some differential-geometric aspects of the Torelli map

In this note we survey recent results on the extrinsic geometry of the Jacobian locus inside $\mathsf{A}_g$. We describe the second fundamental form of the Torelli map as a multiplication map, recall the relation between totally geodesic subvarieties and Hodge loci and survey various results related to totally geodesic subvarieties and the Jacobian locus.Comment: To appear on Boll. UMI, special volume in memory of Paolo de Bartolomei

Combining system dynamic model and CLUE-S model to improve land use scenario analyses at regional scale: A case study of Sangong watershed in Xinjiang, China

Uses of models of land use change are primary tools for analyzing the causes and consequences of land use changes, assessing the impacts of land use change on ecosystems and supporting land use planning and policy. However, no single model is able to capture all of key processes essential to explore land use change at different scales and make a full assessment of driving factors and impacts. Based on the multi-scale characteristics of land use change, combination and integration of currently existed models of land use change could be a feasible solution. Taken Sangong watershed as a case study, this paper describes an integrated methodology in which the conversion of land use and its effect model (CLUE), a spatially explicit land use change model, has been combined with a system dynamic model (SD) to analyze land use dynamics at different scales. A SD model is used to calculate area changes in demand for land types as a whole while a CLUE model is used to transfer these demands to land use patterns. Without the spatial consideration, the SD model ensures an appropriate treatment of macro-economic, demographic and technology developments, and changes in economic policies influencing the demand and supply for land use in a specific region. With CLUE model the land use change has been simulated at a high spatial resolution with the spatial consideration of land use suitability, spatial policies and restrictions to satisfy the balance between land use demand and supply. The application of the combination of SD and CLUE model in Sangong watershed suggests that this methodology have the ability to reflect the complex behaviors of land use system at different scales to some extent and be a useful tool for analysis of complex land use driving factors such as land use policies and assessment of its impacts on land use change. The established SD model was fitted or calibrated with the 1987-1998 data and validated with the 1998-2004 data; combining SD model with CLUE-S model, future land use scenarios were analyzed during 2004-2030. This work could be used for better understanding of the possible impacts of land use change on terrestrial ecosystem and provide scientific support for land use planning and managements of the watershed. (C) 2010 Elsevier B.V. All rights reserved

Long-term clinical, immunologic and virologic impact of glucocorticoids on the chronic phase of HIV infection

BACKGROUND: To test the hypothesis of down-regulating the increased immune system activation/destruction process associated with chronic HIV infection, we focused our interest on prednisolone (PDN), because we had showed that, in vitro, PDN had a strong anti-apoptotic activity on activated T cells of HIV-infected patients and no effect on viral replication. We thus designed in 1992 a pilot study to evaluate the clinical, immunologic and virologic effects of PDN. The drug was given to a group of 44 patients with CD4 T cells over 200/μl. After one year, no patient had developed clinical AIDS and the mean CD4 T cell count of the group had increased from 441 ± 21 cells/μl to 553 ± 43 cells/μl. Moreover, markers of immune activation had dropped back to normal levels while the mean viral load of the group had remained unchanged. Here we explore the long-term clinical, immunologic, and virologic impact of prednisolone on the chronic phase of HIV infection. METHODS: Retrospective study over 10 years starting between July 1992 and February 1993. A total of 44 patients with CD4 cells/μl ranging from 207 to 775 were treated with prednisolone, 0.5 mg/kg/d, over 6 months and 0.3 mg/kg/d thereafter. RESULTS: No clinical AIDS developed under prednisolone; side effects of the drug were mild. CD4 cells which increased from 421 cells/μl at entry to 625 cells/μl at day 15, slowly decreased to reach 426 cells/μl after two years; T cell apoptosis and activation markers dropped within 15 days to normal levels and reincreased slowly thereafter. Serum viral loads remained stable. The percentage of patients maintaining CD4 cells over entry was 43.2% at two years, 11.4% at five years and 4.6% at 10 years. Initial viral load was highly predictive of the rate of CD4 decrease under prednisolone. CONCLUSIONS: Prednisolone postponed CD4 cell decrease in a viral load dependent manner for a median of two years and for up to 10 years in a fraction of the patients with a low viral load. These findings might stimulate clinical trials as well as biological research on the role of antiapoptotic drugs in HIV infection

Alterations in vascular function in primary aldosteronism - a cardiovascular magnetic resonance imaging study

Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV).<p></p> Methods: We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass.<p></p> Results: Subjects with PA had significantly lower aortic distensibilty and higher PWV compared to EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including aging. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular aging. As expected, aortic distensibility and PWV were closely correlated.<p></p> Conclusion: These results demonstrate that PA patients display increased arterial stiffness compared to EH, independent of vascular aging. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.<p></p&gt