Variable selection in robust joint mean and covariance model for longitudinal data analysis

In longitudinal data analysis, a correct specification of the within-subject covariance matrix cultivates an efficient estimation for mean regression coefficients. In this article, we consider robust variable selection method in a joint mean and covariance model. We propose a set of penalized robust generalized estimating equations to simultaneously estimate the mean regression coefficients, the generalized autoregressive coefficients, and innovation variances introduced by the modified Cholesky decomposition. The set of estimating equations select important covariate variables in both mean and covariance models together with the estimating procedure. Under some regularity conditions, we develop the oracle property of the proposed robust variable selection method. Finally, a simulation study and a detailed data analysis are carried out to assess and illustrate the small sample performance; they show that the proposed method performs favorably by combining the robustifying and penalized estimating techniques together in the joint mean and covariance model.published_or_final_versio

Regenerating plants from in vitro culture of Erigeron breviscapus leaves

A protocol to efficiently achieve plant regeneration from leaf explants of Erigeron breviscapus (Compositae) has been developed. Leaf explants produced calli on Murashige and Skoog’s (1962) basal medium (MS) supplemented with 6-benzylaminopurine (BAP) (0.4 mM) and 2,4-dichlorophenoxyacetic acid (2,4-D) (0.4-22.6 mM) under a 16-h photoperiod. Direct adventitious shoots were induced from leaf explants on MS medium containing BAP (22.2 mM) and IAA (5.7 mM) under the light treatment. The effect of the dark incubation on shoot regeneration from leaves indicated that 15 days of darkness permitted a higher regeneration frequency (82.6%) on the medium supplemented with BAP (4.4 mM) and indole-3- acetic acid (IAA) (0.6 mM). Regenerated shoots were rooted on MS medium with or without naphthaleneacetic acid (NAA). Plantlets were cultivatable in the greenhouse after acclimatization

Current concepts in odontohypophosphatasia form of hypophosphatasia and report of two cases

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Extract of Zanthoxylum bungeanum maxim seed oil reduces hyperlipidemia in hamsters fed high-fat diet via activation of peroxisome proliferator-activated receptor γ

Purpose: To investigate the anti-hyperlipidaemic effect of extract of Zanthoxylum bungeanum Maxim. seed oil (EZSO) on high-fat diet (HFD)-induced hyperlipidemic hamsters.Methods: Following feeding with HFD for 30 days, hyperlipidemic hamsters were intragastrically treated with EZSO for 60 days. Serum levels of triglyceride (TG), total cholesterol (TC), low-density-lipoproteincholesterol (LDL-C), nitric oxide (NO) and malondialdehyde (MDA) were analyzed. Protein expression and location of peroxisome proliferator-activated receptor γ (PPARγ) in liver were determined by Western blot and immunohistochemical assays, respectively.Results: EZSO at 5 and 10 g/kg significantly reduced levels of TG by 26 and 23 % (p < 0.05), TC by 19 % (p < 0.01) and 13 % (p < 0.01), LDL-C by 18 % (p < 0.05) and 21 % (p < 0.01), NO by 15 % (p < 0.01) and 31 % (p < 0.01), and MDA by 16 % (p < 0.05) and 30 % (p < 0.01), respectively, in serum of hyperlipidemic hamsters. However, EZSO did not show significant effect on HDL-C level in serum. Furthermore, EZSO at 5 and 10 g/kg markedly promoted protein expression of PPARγ by 71 % (p < 0.05) and 102 % (p < 0.01) in liver tissue of hyperlipidemic hamsters. EZSO also notably increased the content of PPARγ protein in the nucleus of liver cells of hyperlipidemic hamsters.Conclusion: These findings suggest that EZSO can reduce hyperlipidemia and improve oxidative stress in hyperlipidemic hamsters through activation of PPARγ, and that EZSO is a promising novel hypolipidemic health product.Keywords: Zanthoxylum bungeanum, Peroxisome proliferator activated receptor γ, Hyperlipidemia, Hamster, High-fat die

基于模糊度中误差的GPS信号第三民用频率l5的选取研究

Author name used in this publication: 郑作亚Author name used in this publication: 陈永奇Author name used in this publication: 卢秀山Title in Traditional Chinese: 基於模糊度中誤差的GPS信號第三民用頻率L5的選取研究Journal title in Traditional Chinese: 測繪學報2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effects of L-arginine on intestinal development and endogenous arginine-synthesizing enzymes in neonatal pigs

This study aimed to investigate the effects of dietary L-arginine supplementation on the intestinal development of neonatal piglets and the underlying mechanisms. 36 neonatal piglets were randomly allocated into three diet groups: control group (supplemented with 0% L-arginine), 0.4 and 0.8% Larginine groups. When compared with the control, dietary supplementation with L-arginine decreased (P<0.05) blood urea nitrogen (BUN), and improved (P<0.05) serum T3 and insulin level of the piglets on day 11. Arginine and its metabolites (citrulline and ornithine) were elevated, additionally, dietary supplementation with 0.8% L-arginine markedly enhanced jejunal villus height, villus area on day 11 and D-xylose absorption rate on day 19. Dietary supplementation with 0.8% L-arginine increased (P<0.05) activities of maltose and lactose on day 18, respectively. This effect correlated with profound change in enzyme activities as inducible nitric oxide synthetase (iNOS), glutamine synthetase (GS) and ornithine decarboxylase (ODC) were elevated on day 18. The concentrations of spermine was increased (P<0.05) by L-arginine supplementation on day 18. These results collectively suggest that dietary  Larginine supplementation improves protein synthesis and intestinal development of the neonatal pigs, the underlying mechanism includes dietary L-arginine supplementation which regulated the productions of intestinal polyamine in jejunum, and stimulated endogenous arginine-synthesizing enzymes in neonatal piglets.Key words: Neonatal pig, L-arginine, intestinal development, arginine-synthetases

Ferroelectric rods with adjustable dielectric tunability

Author name used in this publication: C. H. Woo2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Antioxidant treatment enhances human mesenchymal stem cell anti-stress ability and therapeutic efficacy in an acute liver failure model

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On the Morphology, Structure and Field Emission Properties of Silver-Tetracyanoquinodimethane Nanostructures

Silver-tetracyanoquinodimethane(Ag-TCNQ) nanostructured arrays with different morphologies were grown by an organic vapor-transport reaction under different conditions. The field emission properties of nanostructured arrays were studied systematically. Their morphology and crystal structure were characterized by SEM and XRD, respectively. It was found that the field emission properties were strongly dependent on the reaction temperature and the initial Ag film thickness. The lowest turn-on field with 10-nm-thick silver film is about 2.0 V/μm, comparable to that of carbon nanotubes. The film crystal structure and the morphology are contributed to the final emission performance