Publications by authors named "Xia Guan"

Studies of the environmental fate through the interactions of particle-associated polycyclic aromatic hydrocarbons (PAHs) with environmentally persistent free radicals (EPFRs) are presented. The formation of PAHs and EPFRs typically occurs side by side during combustion-processes. The laboratory simulation studies of the model PAH molecule 1-Methylnaphthalene (1-MN) interaction with model EPFRs indicate a transformational synergy between these two pollutants due to mutual and matrix interactions.

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Purpose: Rheumatoid arthritis (RA) shows abnormal proliferation, apoptosis, and invasion in fibroblast-like synoviocytes (FLSs). Baicalein (BAI), extracted from , is used as an anticancer drug through inducing cancer cells apoptosis. However, the mechanism of BAI in RA progression still remains unknown.

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Environmentally persistent free radicals (EPFRs) can be detected in ambient PM, cigarette smoke, and soils and are formed through combustion and thermal processing of organic materials. The hazards of EPFRs are largely unknown. In this study, we assess the developmental toxicity of EPFRs and the ability of TEMPOL (4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl) to protect against such hazards using zebrafish embryos.

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Background: Two polymorphisms, -260C>T (rs2569190) and -561C>T (rs5744455), in the CD14 gene have been implicated in susceptibility to cancer. However, the results remain inconclusive. The current meta-analysis was carried out aiming to confirm the function of these two polymorphisms on the susceptibility of cancer.

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The correlation between the content and morphology of FeO and the yields of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied in this work. Three fly ash surrogates containing 1%, 2.5%, and 4% of FeO were prepared and their effects on PCDD/Fs formation were investigated and compared to our previously studied 5% iron oxide sample using 2-monochlorophenol precursor model.

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Transition metal oxides present in waste incineration systems have the ability to catalyze the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) through surface reactions involving organic dioxin precursors. However, studies have concentrated on the catalytic effects of individual transition metal oxides, while the complex elemental composition of fly ash introduces the possibility of synergistic or inhibiting effects between multiple, catalytically active components. In this study, we have tested fly ash surrogates containing different ratios (by weight) of iron (III) oxide and copper (II) oxide.

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We investigated the relationship between gonadotropin-releasing hormone receptor (GnRHR) gene polymorphisms and outcome of patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization and embryo transfer (IVF-ET). PCOS patients undergoing IVF-ET were selected, and infertile patients due to dysfunctional oviducts served as controls. GnRHR gene polymorphisms were detected using the polymerase chain reaction-restriction fragment length polymorphism assay.

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Cellulose nanocrystals (CNCs) were analyzed by asymmetric flow field-flow fractionation (AF4) coupled with multiangle light scattering (MALS) detection. Small fractions were collected from the output of the AF4 apparatus for investigation by transmission electron microscopy (TEM). The influence of CNC injection amount, the number of passes through a high-pressure homogenizer, and different CNC sources on the elution behavior and particle size distribution was investigated.

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Objective: To improve the understanding in pathology and provide steady proof for diagnosis and treatment of tethered cord syndrome (TCS), the ultrastructure of filum terminale (FT) with TCS will be researched, respectively.

Methods: Thirty-one fila were sectioned and divided into two groups according to diameter. Twenty-two fila thicker than 2 mm were placed into group 1; nine no thicker than 2 mm were placed into group 2.

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A new type of monolithic trapping columns with high mechanical strength was prepared by thin-layer sol-gel coating method and applied to trapping intact proteins for on-line capillary liquid chromatography. Monolithic trapping columns were fabricated by entrapping C8 reversed-phase particles into the capillary columns through a sol-gel network, which was formed by hydrolysis and polycondensation of methyltriethoxysilane. Hundreds times of trapping/untrapping for intact proteins were carried out.

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In order to optimize two-dimensional liquid chromatographic (2D-LC) columns for highly efficient separation of proteins, several liquid chromatographic columns were investigated and evaluated. Weak anion-exchange (WAX) column was chosen as the first dimension because of its extensive protein separation power. By comparison of different WAX chromatographic columns for human liver protein separation, TSKgel DEAE-5PW column was selected as the first dimension of a 2D-LC system.

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With the developments of proteomic study, multidimensional high performance liquid chromatography technology has attracted increasing interests due to its obvious advantages, such as rapid analysis, high automation and easy combination with mass spectrometry and so on. This review emphasizes the advances of multidimensional high performance liquid chromatography technology, including classical bottom-up methods, top-down techniques and array-based two-dimensional liquid chromatography system, which was designed and set up by our lab to improve the throughput. These techniques showed promising potential applications in proteomics study.

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β-benzene hexachloride (β-BHC), the major metabolite of benzene-hexachloride (BHC), is a weak estrogen-like chemical. It is a known persistent organic pollutant and male reproductive toxicant. However, the mechanism by which β-BHC exposure causes male reproductive toxicity remains unknown.

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One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-Chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown.

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In this work, a novel and facile monolithic enzymatic microreactor was prepared in the fused-silica capillary via a two-step procedure including surface acryloylation and in situ aqueous polymerization/immobilization to encapsulate a single enzyme, and its application to fast protein digestion through a direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS) analysis was demonstrated. At first, vinyl groups on the protein surface were generated by a mild acryloylation with N-acryloxysuccinimide in alkali buffer. Then, acryloylated enzyme was encapsulated into polyacrylates by free-radical copolymerization with acrylamide as the monomer, N,N'-methylenebisacrylamide as the cross-linker, and N,N,N',N'-tetramethylethylenediamine/ammonium persulfate as the initiator.

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