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排序方式: 共有376条查询结果,搜索用时 31 毫秒
91.
Novel biodegradable polyester block copolymers have been synthesized by using well-defined poly(3-hydroxyoctanoate) (PHO) oligomers having a hydroxyl end group and an ester end group with M(n) values of 800, 2,500, 5,300, 8,000, or 20,000 as an elastomeric soft segment and poly(epsilon-caprolactone) as a more crystalline segment. These PHO oligomers prepared by methanolysis were subjected to block copolymerization with epsilon-caprolactone. The chemical structure of the copolymers was confirmed by (1)H NMR and (13)C NMR spectroscopy. All the copolyesters are semi-crystalline and two T(g) were observed by differential scanning calorimetry when the molecular weight of the PHO block is about 20,000. 相似文献
92.
Summary High-performance liquid chromatography (HPLC) has been used to study the adsorption kinetics of proteins on immunoadsorbents.
The adsorption rate constant of human serum albumin (HSA) on monoclonal and polyclonal anti-HSA antibodies immobilized on
a silica HPLC support was determined by saturating the column with repeated pulse injections. Studies on polyclonal immunodsorbents
of different capacities enable evaluation of the contribution of transport to the binding sites.
The adsorption properties of two different monoclonal anti-HSA antibodies immobilized on a chromatographic support were characterized
by different approaches. The location of the epitope on the HSA molecule was determined by enzyme-linked immunoassay (ELISA)
with albumin fragments. The chromatographic method was used to determine the column capacity and the adsorption rate constant
of HSA on the immunoadsorbent. To compare the affinity of the antibodies for the antigen, an indirect ELISA method was used
to determine the equilibrium constant of antigen-antibody association in solution
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th september, 1996. 相似文献
93.
E. Renard A. Deratani F. Djedaini-Pilard B. Perly 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):249-252
Stoichiometric amounts of triethylamine (TEA) were found to enhance the chiral induction by -cyclodextrin (-CD) in the reduction of acetophenone (ACPH) by aqueous NaBH4. The enantioselectivity obtained depends upon the molar ratio -CD:ACPH:TEA. Evidence for the formation of a three-component inclusion compound was obtained from detailled1H and2H NAM studies. The restriction of the molecular motion of the prochiral center probably accounts for the strong enhancement of the chiral induction observed. 相似文献
94.
95.
A convenient synthesis of benzimidazolic bioisosteres of melatonin is described through a regioselective synthesis of 1,6-disubstituted benzimidazoles. 相似文献
96.
Pol-Edern Le Renard Rolf LortzCarmine Senatore Jean-Philippe RapinFranz Buchegger Alke Petri-FinkHeinrich Hofmann Eric DoelkerOlivier Jordan 《Journal of magnetism and magnetic materials》2011,323(8):1054-1063
The biological and therapeutic responses to hyperthermia, when it is envisaged as an anti-tumor treatment modality, are complex and variable. Heat delivery plays a critical role and is counteracted by more or less efficient body cooling, which is largely mediated by blood flow. In the case of magnetically mediated modality, the delivery of the magnetic particles, most often superparamagnetic iron oxide nanoparticles (SPIONs), is also critically involved. We focus here on the magnetic characterization of two injectable formulations able to gel in situ and entrap silica microparticles embedding SPIONs. These formulations have previously shown suitable syringeability and intratumoral distribution in vivo. The first formulation is based on alginate, and the second on a poly(ethylene-co-vinyl alcohol) (EVAL). Here we investigated the magnetic properties and heating capacities in an alternating magnetic field (141 kHz, 12 mT) for implants with increasing concentrations of magnetic microparticles. We found that the magnetic properties of the magnetic microparticles were preserved using the formulation and in the wet implant at 37 °C, as in vivo. Using two orthogonal methods, a common SLP (20 W g−1) was found after weighting by magnetic microparticle fraction, suggesting that both formulations are able to properly carry the magnetic microparticles in situ while preserving their magnetic properties and heating capacities. 相似文献
97.
Julien Ramier Meyssoun Ben Boubaker Mohamed Guerrouache Valérie Langlois Daniel Grande Estelle Renard 《Journal of polymer science. Part A, Polymer chemistry》2014,52(6):816-824
Straightforward and versatile routes to functionalize the surface of poly(3‐hydroxyalkanoate) (PHA) electrospun fibers for improving cell compatibility are reported under relatively mild conditions. The modification of nanofibrous PHAs is implemented through two different methodologies to introduce epoxy groups on the fiber surface: (1) preliminary chemical conversion of double bonds of unsaturated PHAs into epoxy groups, followed by electrospinning of epoxy‐functionalized PHAs blended with nonfunctionalized PHAs, (2) electrospinning of nonfunctionalized PHAs, followed by glycidyl methacrylate grafting polymerization under UV irradiation. The latter approach offers the advantage to generate a higher density of epoxy groups on the fiber surface. The successful modification is confirmed by ATR‐FTIR, Raman spectroscopy, and TGA measurements. Further, epoxy groups are chemically modified via the attachment of a peptide sequence such as Arg‐Gly‐Asp (RGD), to obtain biomimetic scaffolds. Human mesenchymal stromal cells exhibit a better adhesion on the latter scaffolds than that on nonfunctionalized PHA mats. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 816–824 相似文献
98.
99.
100.
D Renard P Robert S Faucheron C Sanchez 《Colloids and surfaces. B, Biointerfaces》1999,12(3-6):113-121
Microparticulated whey proteins (MWP) in suspension or included in a globular protein network revealed that the degree of flocculation was important in the final structure of the material. The MWP dispersions developed an antithixotropic character when low shear rate was applied to the system even at low temperature. Similar results were obtained on globular protein solutions and could be interpreted in terms of an orthokinetic aggregation. MWP participated to the formation and reinforcement of heat-induced β-lactoglobulin (BLG) gels. The mechanical properties of mixed gels demonstrated synergestic effects at low MWP massic fraction (BLG:MWP ratio higher than 2:1). A possible interpretation would be that both interaction of MWP with the network and flocculation of the MWP inside the pores could occur. However, increasing the fraction of MWP induced heterogeneities in the protein network. In particular, micro-phase separation due to steric hindrance effects or thermodynamic incompatibility between the two components could occur and decrease viscoelastic properties of mixed gels. 相似文献