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1.
Lipofundin is the solvent for propofol in the intravenous injection of Propofol-Lipuro® and is used in patients who need intravenous feeding to provide fatty acids and fat for energy. In addition to propofol, Lipofundin also affects the immune modulation of phagocytes. In a previous study, we reported that intravenous propofol effectively decreased Staphylococcus aureus-stimulated reactive oxygen species (ROS) levels, IL-1β secretion, and phagocytosis in RAW264.7 macrophages. It is important to separately assess the effects of pure propofol, Lipofundin, and Propofol-Lipuro. By using an S. aureus-infected RAW264.7 macrophage model, the levels of secreted IL-1β in cell supernatants were determined by ELISA. IL-1β mRNA in cell pellets was further analyzed by quantitative polymerase chain reaction (qPCR), and Western blotting was performed to detect pro-IL-1β synthesis. Total ROS levels were determined by a luminol chemiluminescence assay. Compared with pure propofol, treatment with clinically relevant concentrations of Propofol-Lipuro and Lipofundin obviously reduced IL-1β secretion (>85% inhibition), S. aureus-stimulated ROS production (50% inhibition), and phagocytosis (>60% inhibition) to similar levels. Treatment with pure propofol alone significantly decreased IL-1β mRNA levels and pro-IL-1β protein synthesis, and slightly inhibited phagocytosis. In contrast, treatment with Propofol-Lipuro did not influence IL-1β mRNA or pro-IL-1β protein expression, even though treatment with Lipofundin increased the levels of both IL-1β mRNA and its precursor protein. In conclusion, IL-1β secretion is regulated at the posttranslational level. Lipofundin mediated the major effect of Propofol-Lipuro on the inhibition of IL-1β secretion, ROS production, and phagocytosis in S. aureus-infected RAW264.7 cells.  相似文献   

2.
Alternative strategies beyond current chemotherapy and radiation therapy regimens are needed in the treatment of advanced stage and recurrent endometrial cancers. There is considerable promise for biologic agents targeting the extracellular signal-regulated kinase (ERK) pathway for treatment of these cancers. Many downstream substrates of the ERK signaling pathway, such as glycogen synthase kinase 3β (GSK3β), and their roles in endometrial carcinogenesis have not yet been investigated. In this study, we tested the importance of GSK3β inhibition in endometrial cancer cell lines and in vivo models. Inhibition of GSK3β by either lithium chloride (LiCl) or specific GSK3β inhibitor VIII showed cytostatic and cytotoxic effects on multiple endometrial cancer cell lines, with little effect on the immortalized normal endometrial cell line. Flow cytometry and immunofluorescence revealed a G2/M cell cycle arrest in both type I (AN3CA, KLE, and RL952) and type II (ARK1) endometrial cancer cell lines. In addition, LiCl pre-treatment sensitized AN3CA cells to the chemotherapy agent paclitaxel. Administration of LiCl to AN3CA tumor-bearing mice resulted in partial or complete regression of some tumors. Thus, GSK3β activity is associated with endometrial cancer tumorigenesis and its pharmacologic inhibition reduces cell proliferation and tumor growth.  相似文献   

3.
The issue of whether ERK activation determines matrix synthesis or degradation in osteoarthritis (OA) pathogenesis currently remains controversial. Our previous study shows that PLCγ1 and mTOR are involved in the matrix metabolism of OA cartilage. Investigating the interplays of PLCγ1, mTOR and ERK in matrix degradation of OA will facilitate future attempts to manipulate ERK in OA prevention and therapy. Here, cultured human normal chondrocytes and OA chondrocytes were treated with different inhibitors or transfected with expression vectors, respectively. The levels of ERK, p-ERK, PLCγ1, p-PLCγ1, mTOR, p-mTOR and MMP-13 were then evaluated by Western blotting analysis. The results manifested that the expression level of ERK in human OA chondrocytes was lower than that in human normal articular chondrocytes, and the up-regulation of ERK could promote matrix synthesis, including the decrease in MMP-13 level and the increase in Aggrecan level in human OA chondrocytes. Furthermore, the PLCγ1/ERK axis and a mutual inhibition of mTOR and ERK were observed in human OA chondrocytes. Interestingly, activated ERK had no inhibitory effect on MMP-13 expression in PLCγ1-transformed OA chondrocytes. Combined with our previous study, the non-effective state of ERK activation by PLCγ1 on MMP-13 may be partly attributed to the inhibition of the PLCγ1/mTOR axis on the PLCγ1/ERK axis. Therefore, the study indicates that the mutual inhibition of ERK and mTOR is involved in PLCγ1-mediated MMP-13 expression in human OA chondrocytes, with important implication for the understanding of OA pathogenesis as well as for its prevention and therapy.  相似文献   

4.
Hepatitis C virus (HCV) has been recognized to be both a hepato- and lymphotropic virus. HCV lymphotropism represents an essential detail in the pathogenesis of virus-related autoimmune and lymphoproliferative disorders, ranging from clonal expansion of B-cells with organ and non-organ-specific autoantibody production up to overt non-Hodgkin’s lymphoma along a continuous step-by-step model of B-cell lymphomagenesis, where the intermediated mixed cryoglobulinemia could be considered as a stage of suppressible antigen-driven lymphoproliferation. The HCV long-lasting extrahepatic replicative state generates an abnormal systemic immunological response, including rheumatoid factor (RF) and cryo- and non-cryoprecipitable immune complexes, as well as clinical manifestations, comprising dermatitis, polyarthralgias and arthritis, pulmonary disease, aplastic anemia, glomerulonephritis and vasculitis. The mechanism of these extra-hepatic disorders is thought of as linked to immune complex disease, but their pathogenesis is poorly clarified. Immune-suppressive treatment could induce high-level hepatitis C viremia and impair hepatic disease. We report a female patient, whose chronic HCV-related liver cirrhosis with associated explosive, but oligosymptomatic lymphoproliferative immune response, i.e., RF beyond three thousand times the upper of normal range (unr), type II cryoglobulinemia with cryocrit 40% and monoclonal gammopathy IgM-k, has been successfully and safely treated by long-lasting (sixty-six months) combined antiviral therapy (pegylated interferon alfa and ribavirin), at moderate and tapering dose regimen, prolonged for nearly 24 months after the first viral suppression. At the last follow-up (fifty-one months), the patient was showing very-long term antiviral response, progressive decline of secondary immune activation and absence of significant side-effects. Further research is required to fully verify the real impact on therapeutic choice/regimen.  相似文献   

5.
Astaxanthin, a potent antioxidant carotenoid, plays a major role in modulating the immune response. In this study, we examined the immunomodulatory effects of astaxanthin on cytokine production in primary cultured lymphocytes both in vitro and ex vivo. Direct administration of astaxanthin (70–300 nM) did not produce cytotoxicity in lipopolysaccharide (LPS, 100 µg/ mL)- or concanavalin A (Con A, 10 µg/ mL)-activated lymphocytes, whereas astaxanthin alone at 300 nM induced proliferation of splenic lymphocytes (p < 0.05) in vitro. Although astaxanthin, alone or with Con A, had no apparent effect on interferon (INF-γ) and interleukin (IL-2) production in primary cultured lymphocytes, it enhanced LPS-induced INF-γ production. In an ex vivo experiment, oral administration of astaxanthin (0.28, 1.4 and 7 mg/kg/day) for 14 days did not cause alterations in the body or spleen weights of mice and also was not toxic to lymphocyte cells derived from the mice. Moreover, treatment with astaxanthin significantly increased LPS-induced lymphocyte proliferation ex vivo but not Con A-stimulated lymphocyte proliferation ex vivo. Enzyme linked immunosorbent assay (ELISA) analysis revealed that administration of astaxanthin significantly enhanced INF-γ production in response to both LPS and Con A stimulation, whereas IL-2 production increased only in response to Con A stimulation. Also, astaxanthin treatment alone significantly increased IL-2 production in lymphocytes derived from mice, but did not significantly change production of INF-γ. These findings suggest that astaxanthin modulates lymphocytic immune responses in vitro, and that it partly exerts its ex vivo immunomodulatory effects by increasing INF-γ and IL-2 production without inducing cytotoxicity.  相似文献   

6.
The complement components C8α, C8β and C9 have important roles in the innate immune system against invading microorganisms. Partial cDNA sequences of the Pf_C8α, Pf_C8β and Pf_C9 genes (Pf: abbreviation of Pelteobagrus fulvidraco) were cloned from yellow catfish. The Pf_C8α, Pf_C8β and Pf_C9 genes showed the greatest amino acid similarity to C8α (54%) and C8β (62%) of zebrafish and to C9 (52%) of grass carp, respectively. Ontogenetic expression analyses using real-time quantitative PCR suggested that the three genes may play crucial roles during embryonic and early larval development. The mRNA expressions of the three genes were all at the highest levels in liver tissue, and at lower or much lower levels in 16 other tissues, demonstrating that the liver is the primary site for the protein synthesis of Pf_C8α, Pf_C8β and Pf_C9. Injection of Aeromonas hydrophila led to up-regulation of the three genes in the spleen, head kidney, kidney, liver and blood tissues, indicating that the three genes may contribute to the host’s defense against invading pathogenic microbes. An increased understanding of the functions of the Pf_C8α, Pf_C8β and Pf_C9 genes in the innate immunity of yellow catfish will help enhance production of this valuable freshwater species.  相似文献   

7.
8.
It is known that fatty acids (FA) regulate lipid metabolism by modulating the expression of numerous genes. In order to gain a better understanding of the effect of individual FA on lipid metabolism related genes in rainbow trout (Oncorhynchus mykiss), an in vitro time‐course study was implemented where twelve individual FA (butyric 4:0; caprylic 8:0; palmitic (PAM) 16:0; stearic (STA) 18:0; palmitoleic16:1n‐7; oleic 18:1n‐9; 11‐cis‐eicosenoic 20:1n‐9; linoleic (LNA) 18:2n‐6; α‐linolenic (ALA) 18:3n‐3; eicosapentenoic (EPA) 20:5n‐3; docosahexaenoic (DHA) 22:6n‐3; arachidonic (ARA) 20:4n‐6) were incubated in rainbow trout liver slices. The effect of FA administration over time was evaluated on the expression of leptin, PPARα and CPT‐1 (lipid oxidative related genes). Leptin mRNA expression was down regulated by saturated fatty acids (SFA) and LNA, and was up regulated by monounsaturated fatty acids (MUFA) and long chain PUFA, whilst STA and ALA had no effect. PPARα and CPT‐1mRNA expression were up regulated by SFA, MUFA, ALA, ARA and DHA; and down regulated by LNA and EPA. These results suggest that there are individual and specific FA induced modifications of leptin, PPARα and CPT‐1 gene expression in rainbow trout, and it is envisaged that such results may provide highly valuable information for future practical applications in fish nutrition.  相似文献   

9.
Mangiferin is a natural immunomodulator found in plants including mango trees. The effects of mangiferin on chondrogenesis and cartilage repair have not yet been reported. This study was designed to determine the effect of mangiferin on chondrogenic differentiation in IL-1β-stimulated mesenchymal stem cells (MSCs) from subchondral bone and to explore the mechanisms underlying these effects. MSCs were isolated from the subchondral bone of rabbit and treated with mangiferin alone and/or interleukin-1β (IL-1β). Mangiferin induced chondrogenic differentiation in MSCs by upregulating transforming growth factor (TGF)-β, bone morphogenetic protein (BMP)-2, and BMP-4 and several key markers of chondrogenesis, including sex-determining region Y–box (SRY-box) containing gene 9 (SOX9), type 2α1 collagen (Col2α1), cartilage link protein, and aggrecan. In IL-1β-stimulated MSCs, mangiferin significantly reversed the production of TGF-β, BMP-2, BMP-4, SOX9, Col2α1, cartilage link protein, and aggrecan, as well as matrix metalloproteinase (MMP)-1, MMP-13, and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS5). Mangiferin upregulated the phosphorylation of Smad 2, Smad 3, Smad 1/5/8, and SOX9 in IL-1β-stimulated MSCs. In the presence of mangiferin, SOX9 siRNA suppressed the activation of Smad 2, Smad 3, Smad 1/5/8, aggrecan, and Col2α1 expression. In conclusion, mangiferin exhibits both chondrogenic and chondroprotective effects on damaged MSCs and mediates these effects by targeting multiple aspects of the Smad and SOX9 signaling pathways.  相似文献   

10.
Human mesenchymal stem cells (MSCs) have the potential to differentiate into nucleus pulposus (NP)-like cells under specific stimulatory conditions. Thus far, the effects of bone morphogenetic protein 3 (BMP3) and the cocktail effects of BMP3 and transforming growth factor (TGF)-β on MSC proliferation and differentiation remain obscure. Therefore, this study was designed to clarify these unknowns. MSCs were cultured with various gradients of BMP3 and BMP3/TGF-β, and compared with cultures in basal and TGF-β media. Cell proliferation, glycosaminoglycan (GAG) content, gene expression, and signaling proteins were measured to assess the effects of BMP3 and BMP3/TGF-β on MSCs. Cell number and GAG content increased upon the addition of BMP3 in a dose-dependent manner. The expression of COL2A1, ACAN, SOX9, and KRT19 increased following induction with BMP3 and TGF-β, in contrast to that of COL1A1, ALP, OPN, and COMP. Smad3 phosphorylation was upregulated by BMP3 and TGF-β, but BMP3 did not affect the phosphorylation of extracellular-signal regulated kinase (ERK) 1/2 or c-Jun N-terminal kinase (JNK). Our results reveal that BMP3 enhances MSC proliferation and differentiation into NP-like cells, as indicated by increased cell numbers and specific gene expressions, and may also cooperate with TGF-β induced positive effects. These actions are likely related to the activation of TGF-β signaling pathway.  相似文献   

11.
Jo SJ  Choi WW  Lee ES  Lee JY  Park HS  Moon DW  Eun HC  Chung JH 《Lipids》2011,46(6):487-494
In this study, cells from the stromal vascular fraction of human subcutaneous tissues were induced to differentiate toward adipose cells in vitro for 2 weeks. During adipogenic differentiation, we followed the chronological changes in their morphology with Coherent anti-Stokes Raman scattering (CARS) microscopy and checked the PPAR-γ and UCP-1 expression with RT-PCR. On day 4 after inducing adipogenic differentiation, CARS imaging showed multiple small lipid droplets (LD) distributed peripherally along the cellular membrane. PPAR-γ began to express at this time and increased until day 14 at a steady rate. On day 7, the cells appeared as brown adipocytes with numerous small LD throughout the cytoplasm, and the mRNA level of UCP-1 rose abruptly by 6- to 7-fold. After an additional 7 days, CARS imaging showed the development of a large LD, which is characteristic of white adipocytes, and the mRNA level of UCP-1 slumped significantly. These results demonstrate the possibility that ADSC pass through a brown adipocyte-like stage while differentiating into white adipocytes.  相似文献   

12.
Of the antioxidant vitamin E isoforms, α-tocopherol (αT) and γ-tocopherol (γT) are the most abundant in the human diet, and αT is consumed from both natural and synthetic sources. αT and γT may differentially impact inflammation and influence cardiovascular outcomes, in part by modulating gene expression. The goal of this study was to compare the effects of natural αT, synthetic αT, and γT on gene expression in two human cell lines. Human aortic smooth muscle cells (HASMC) and endothelial cells (HAEC) were either: (1) treated with 25 μM tocopherols alone, or (2) pretreated with tocopherols prior to a pro-inflammatory cytokine (tumor necrosis factor-alpha, TNF-α) stimulation. The expression of atherosclerosis-related genes was measured using RT2 Profiler PCR arrays. Tocopherol treatments alone did not significantly modulate the expression of genes in unstimulated HASMC or HAEC. TNF-α stimulation significantly upregulated genes involved with apoptosis and stress response in both cell lines. Pretreating cells with tocopherols did not normalize the gene expression changes induced by TNF-α. However, αT pretreatments, but not γT pretreatments, attenuated TNF expression in both HASMC and HAEC. These findings suggest that under stimulated conditions, αT modestly modulates the expression of selective genes and that αT may be more anti-inflammatory than γT.  相似文献   

13.
Mycenarubin C, a previously unknown red pyrroloquinoline alkaloid, was isolated from fruiting bodies of the mushroom Mycena rosea and its structure was elucidated mainly by NMR spectroscopy and mass spectrometry. Unlike mycenarubin A, the major pyrroloquinoline alkaloid in fruiting bodies of M. rosea, mycenarubin C, contains an eight-membered ring with an additional C1 unit that is hitherto unprecedented for pyrroloquinoline alkaloids known in nature. Incubation of mycenarubin A with an excess of formaldehyde revealed that mycenarubin C was generated nearly quantitatively from mycenarubin A. An investigation into the formaldehyde content of fresh fruiting bodies of M. rosea showed the presence of considerable amounts of formaldehyde, with values of 5 μg per gram of fresh weight in fresh fruiting bodies. Although mycenarubin C did not show bioactivity against selected bacteria and fungi, formaldehyde inhibits the growth of the mycoparasite Spinellus fusiger at concentrations present in fruiting bodies of M. rosea. Therefore, formaldehyde might play an ecological role in the chemical defence of M. rosea against S. fusiger. In turn, S. fusiger produces gallic acid—presumably to detoxify formaldehyde by reaction of this aldehyde with amino acids and gallic acid to Mannich adducts.  相似文献   

14.
We characterized the oxidative stress (OS) status by the levels of reduced/oxidized glutathione (GSH/GSSG), malondialdehyde (MDA) and the mutagenic base 8-oxo-7′8-dihydro-2′-deoxyguanosine (8-oxo-dG) in human gastric carcinoma (HGC) samples and compared the results with normal tissue from the same patients. We also analyzed 8-oxo-dG in peripheral mononuclear cells (PMNC) and urine from healthy control subjects and in affected patients in the basal state and one, three, six, nine and twelve months after tumor resection. The levels of DNA repair enzyme mRNA expression (hOGG1, RAD51, MUYTH and MTH1) were determined in tumor specimens and compared with normal mucosa. Tumor specimens exhibited increased levels of MDA and 8-oxo-dG compared with normal gastric tissue. GSH levels were also increased, while GSSG levels remained stable. DNA repair enzyme mRNA expression was induced in the tumor tissues. Levels of 8-oxo-dG were significantly elevated in both urine and PMNC of gastric cancer patients compared with healthy controls. After gastrectomy, the levels of the damaged base in urine and PMNC decreased progressively to values close to those found in the healthy population. The high levels of 8-oxo-dG in urine may be related to the increased induction of DNA repair activity in tumor tissue, and the changes observed after tumor resection support its potential use as a tumor marker.  相似文献   

15.
Increasing evidences suggest that inflammation plays an important role in the pathogenesis of coronary artery disease (CAD). Numerous inflammatory cytokines and related genes mediate adverse cardiovascular events in patients with CAD, such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and Homer in the present study. The study was carried out on 163 CAD patients at different stages and 68 controls. The gene expression of Homer1, Homer2, Homer3, IL-1β, and TNF-α in the peripheral blood leukocytes were measured by real-time polymerase chain reaction. The mRNA levels of Homer1, IL-1β, and TNF-α in CAD patients were significantly higher than those in the control group, but not Homer2 and Homer3. However, there was no considerable difference in the mRNA levels of Homer1, IL-1β, and TNF-α among AMI, UAP, and SAP three subgroups of CAD. The receiver operating characteristic (ROC) curves showed that Homer1 had a better diagnostic value for UAP patients compared with IL-1β and TNF-α. Like IL-1β and TNF-α, Homer1 may also be an important participant of atherosclerotic plaque development and eventually rupture. The results of the present study may provide an important basis for diagnosing CAD patients, and provide new therapeutic targets for CAD.  相似文献   

16.
This study was carried out to determine the effects of flaxseed oil administration on gene expression levels related to insulin, lipid and inflammation in overweight diabetic patients with coronary heart disease (CHD). This randomized double‐blind, placebo‐controlled trial was conducted among 60 diabetic patients with CHD. Subjects were randomly allocated into two groups to intake either 1000 mg n‐3 fatty acid from flaxseed oil containing 400 mg α‐Linolenic acid [ALA (18:3n‐3)] (n = 30) or placebo (n = 30) twice a day for 12 weeks. Gene expression related to insulin, lipid and inflammation were quantified in peripheral blood mononuclear cells (PBMC) of diabetic patients with CHD with RT‐PCR method. Results of RT‐PCR demonstrated that after the 12‐week intervention, compared with the placebo, flaxseed oil supplementation could up‐regulate gene expression of peroxisome proliferator‐activated receptor gamma (PPAR‐γ) (P = 0.02) in PBMC of diabetic patients with CHD. In addition, compared with the placebo, taking flaxseed oil supplements down‐regulated gene expression levels of lipoprotein(a) [LP(a)] (P = 0.001), interleukin‐1 (IL‐1) (P = 0.001) and tumor necrosis factor alpha (TNF‐α) (P = 0.02) in PBMC of diabetic patients with CHD. We did not observe any significant effect of flaxseed oil supplementation on gene expression levels of low‐density lipoprotein receptor (LDLR), IL‐8 and transforming growth factor beta (TGF‐β) in PBMC of diabetic patients with CHD. Overall, flaxseed oil supplementation for 12 weeks in diabetic patients with CHD significantly improved gene expression levels of PPAR‐γ, LP(a), IL‐1 and TNF‐α, but did not influence LDLR, IL‐8 and TGF‐β.  相似文献   

17.
Genistein has been reported to stimulate luminal HCO3 secretion. We hypothesized that genistein mediates this effect via SLC26A6 and SLC4A4 (NBCe1) transporters. Our study aimed to: investigate changes in uterine fluid pH, Na+ and HCO3 concentration and expression of uterine SLC26A6 and NBCe1 under genistein effect. Ovariectomized adult female rats received 25, 50 and 100 mg/kg/day genistein for a week with and without ICI 182780. A day after the last injection, in vivo uterine perfusion was performed to collect uterine fluid for Na+, HCO3 and pH determination. The animals were then sacrificed and uteri were removed for mRNA and protein expression analyses. SLC26A6 and NBCe1-A and NBCe1-B distribution were visualized by immunohistochemistry (IHC). Genistein at 50 and 100 mg/kg/day stimulates uterine fluid pH, Na+ and HCO3 concentration increase. Genistein at 100 mg/kg/day up-regulates the expression of SLC26A6 and SLC4A4 mRNA, which were reduced following concomitant ICI 182780 administration. In parallel, SLC26A6 and NBCe1-B protein expression were also increased following high dose genistein treatment and were localized mainly at the apical membrane of the luminal epithelia. SLC26A6 and NBCe1-B up-regulation by genistein could be responsible for the observed increase in the uterine fluid pH, Na+ and HCO3 concentration under this condition.  相似文献   

18.
Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na(+), K(+)-ATPase are expressed in primary chondrocytes. Some of these isoforms have previously been reported to be expressed exclusively in electrically excitable cells (i.e., cardiomyocytes and neurons). Studying the distribution of Na(+), K(+)-ATPase isoforms in chondrocytes makes it possible to document the diversity of isozyme pairing and to clarify issues concerning Na(+), K(+)-ATPase isoform abundance and the physiological relevance of their expression. In this study, we investigated the expression of Na(+), K(+)-ATPase in a human chondrocyte cell line (C-20/A4) using a combination of immunological and biochemical techniques. A panel of well-characterized antibodies revealed abundant expression of the α1, β1 and β2 isoforms. Western blot analysis of plasma membranes confirmed the above findings. Na(+), K(+)-ATPase consists of multiple isozyme variants that endow chondrocytes with additional homeostatic control capabilities. In terms of Na(+), K(+)-ATPase expression, the C-20/A4 cell line is phenotypically similar to primary and in situ chondrocytes. However, unlike freshly isolated chondrocytes, C-20/A4 cells are an easily accessible and convenient in vitro model for the study of Na(+), K(+)-ATPase expression and regulation in chondrocytes.  相似文献   

19.
20.
The search for innovative and well-defined organic–inorganic hybrid materials demands that the interplay between polymerization reactions, chemical reactivity, and physical adsorption be fully understood. We examine the case study of the thermal polymerization of styrene in the presence of silica, and the effect of pre-irradiation of silica with γ-rays. The effect of adsorption of styrene-derived radical species on the silica support and polymerization conditions on free and grafted (unextractable) polystyrenes and on polymerization mechanism is discussed on the basis of previous literature findings and new data. Evidence is provided of silica derivatization with various species besides polystyrene (13C CPMAS NMR), including products from a β-scission of the adsorbed radical intermediates ensuing oxygen donation from the silica network. The polymerization mechanism can be cationic as well as radical, depending on reaction conditions, and the cationic route prevails in the grafting of polystyrene from silica, resulting in a bimodal molecular weight distribution.  相似文献   

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