Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(2-hydroxyethyl methacrylate/ethylenglycol dimethacrylate) beads were grafted with poly(glycidylmethacrylate) via surface initiated atom transfer radical polymerization. Epoxy groups of the grafted polymer were modified in to sulfone groups. Sulfonated beads were characterized by swelling studies, FT-IR, SEM and elemental analysis, and were used for reversible immobilization of lipase. Under given experimental conditions, the beads had an adsorption capacity of 44.7 mg protein/g beads. The adsorbed lipase on beads retained up to 67.4% of its initial activity. The immobilized lipase exhibited improved thermal and storage stabilities over those of the free enzyme. The immobilized lipase could desorb 1.0 M NaCl solution at pH 8.0, and the sulfonated beads can be repeatedly charged with fresh enzyme after inactivation upon use.
 ...
PMID:Reversible immobilization of Candida rugosa lipase on fibrous polymer grafted and sulfonated p(HEMA/EGDMA) beads. 1935 Feb 76

Poly(1,3-bis-(p-carboxyphenoxy propane)-co-(sebacic anhydride) (P(CPP-SA)) have the anhydride bonds in copolymer backbone, which are available for degradation on the base of passive hydrolysis. This chemical structure made it degraded within a short time in linear degradation rate. For this property, polyanhydrides are one of the most suitable biodegradable polymers employed as drug carriers. This paper aimed at researching the erosion and degradation of P(CPP-SA) microspheres with CPP/SA monomer ratios of 20:80, 35:65 and 50:50. In vitro protein release from the microspheres was also investigated in this paper. Human serum albumin (HSA) was used as the model protein. In this research, the microspheres degradation and drug release rate from microspheres can be adjusted by altering the CPP/SA ratios of P(CPP-SA). The features of surface erosion were observed in SEM. The structural integrity of HSA extracted from microspheres was detected by gel permeation chromatography, compared with native HSA. The results showed HSA remained its molecule weight after encapsulated.
 ...
PMID:Preparation and characterization of protein-loaded polyanhydride microspheres. 1942 77

The ferrocene/Poly(vinyl pyrrolidone) (PVP) composite membranes have been successfully prepared by using electrospinning and polarization coating techniques, respectively. The composite membranes were characterized by means of SEM (scanning electron microscopy), UV-vis absorption spectra, FT-IR (Fourier transform infrared), XRD (X-ray diffraction) and a radio frequency (RF) impedance/capacitance material analyzer. Results showed that the dielectric constants of the ferrocene/PVP composite nanofiber membranes were lower than the coating membranes. The dielectric constants of nanofiber membranes were decreasing with the increasing amount of ferrocene in the solvent, but those of coating membranes were increasing with the increasing amount of ferrocene.
 ...
PMID:Preparation and dielectric property investigation of ferrocene/poly(vinyl pyrrolidone) composite membranes. 1944 75

Poly(epsilon-caprolactone) (PCL) implants containing praziquantel (PZQ), a broad-spectrum antiparasite drug, are fabricated by injection molding and characterized in terms of content uniformity, morphology, drug physical state and stability. In vitro drug release from the implants is also studied. It is found that drug is dispersed uniformly in all implants and keeps stable over 365 days at 4 degrees C/60% RH. X-ray diffraction analysis reveals that PZQ exists primarily in its crystalline state in implants with high drug contents (50% and 25%). All implants exhibit similar release behaviors and about 70% of the drug is released after 365 days. The cross-sections of all implants present two distinct zones (i.e. peripheral white zone and inner pink zone) and the boundary between the two zones changes as time progresses. Drug content in the white zone is very low (less than 1%), but drug content in the pink zone is almost the same as the predefined value. Porous structures in the white zone but dense structures in the pink zone are observed by SEM. Obvious PCL degradation occurs till up to 365 days. These results show that the release process of PZQ is a gradual diffusion from the exterior to the interior of the implants.
 ...
PMID:Characterization and in vitro release of praziquantel from poly(epsilon-caprolactone) implants. 1944 18

Poly(ether-ester urethane)s (PUs) multiblock co-polymers were synthesized from telechelic hydroxylated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(ethylene glycol) (PEG) via a melting polymerization (MP) process using 1,6-hexamethylene diisocyanate (HDI) as a non-toxic coupling agent for the first time. The PHBHHx segments and PEG segments in the multiblock co-polymers behaved as a hard, hydrophobic and a soft, hydrophilic part, respectively. Their chemical structures and molecular characteristics were studied by gel-permeation chromatography (GPC), (1)H-NMR and Fourier transform infrared spectroscopy (FT-IR). The PU produced via the MP method showed a higher molecular weight than those resulting from the solvent polymerization (SP) reported previously. Thermal properties showed enhanced thermal stability with semi-crystalline morphology via incorporation of PEG. The segments compositions evaluated from thermogravimetric analysis (TGA) two-step thermal decomposition profiles suggested that MP enhanced the reactivity of PEG compared with the SP process. It was in good agreement with those calculated from (1)H-NMR, as well as the precursor feed ratio, respectively. Water contact angle measurements revealed that surface hydrophilicity of the PUs was enhanced by incorporating the PEG segment into PHBHHx polymer backbone. The mechanical properties assessment of the PUs recorded an improved and adjustable ductility and toughness than pure PHBHHx while preserving the tensile strength. Samples synthesized via MP were resistant to hydrolytic and lipase degradation, yet the multiblock co-polymers incorporating the highest amount of PEG degraded at the highest rate. SEM studies revealed that the surface of the PU films became increasingly porous as the degradation proceeded. Implantation of PU in mouse abdominal cavity indicated that tissue regeneration and tissue compatibility of PU film was better than that of PHBHHx-only film.
 ...
PMID:Synthesis, characterization and biocompatibility of biodegradable elastomeric poly(ether-ester urethane)s Based on Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and Poly(ethylene glycol) via melting polymerization. 1952 7

In this paper, a simple synthesis method of small-size (about 50 nm in diameter), high magnetic and fluorescent bi-functional silica composite nanoparticles were developed, in which water-soluble Fe3O4 magnetic nanoparticles (MNs) and CdTe quantum dots (QDs) were directly incorporated into a silica shell by reverse microemulsion method. The high luminescent QDs can be used as luminescent marker, while the high magnetic MNs allow the manipulation of the bi-functional silica composite nanoparticles by external magnetic field. Poly (dimethyldiallyl ammonium chloride) was used to balance the electrostatic repulsion between CdTe QDs and silica intermediates to enhance the fluorescence intensity of MNs-QDs/SiO2 composite nanoparticles. The optical property, magnetic property, size characterization of the bi-functional composite nanoparticles were studied by UV-Vis and PL emission spectra, VSM, TEM, SEM. The stabilities toward time, pH and ionic strength and the effect of MNs on the fluorescence properties of bi-functional silica composite nanoparticles were also studied in detail. By modifying the surface of MNs-QDs/SiO2 composite nanoparticles with amino and methylphosphonate groups, biologically functionalized and monodisperse MNs-QDs/SiO2 composite nanoparticles can be obtained. In this work, bi-functional composite nanoparticles were conjugated with FITC labeled goat anti-rabbit IgG, to generate novel fluorescent-magnetic-biotargeting tri-functional composite nanoparticles, which can be used in a number of biomedical application.
 ...
PMID:The synthesis of magnetic and fluorescent bi-functional silica composite nanoparticles via reverse microemulsion method. 1954 73

A new physical route for the production of monodispersed microsphere nanoparticle-polymer composites utilizing a beads milling method, followed by an electrospray method, has been developed. Poly(methyl methacrylate) (PMMA)-TiO2 composites were used as a model to evaluate the performance of this route. SEM images showed that the products were monodispersed, spherical, and nonagglomerate. The mean diameter was in the range of 0.25-1.87 microm, with a standard deviation of 0.06-0.172. TEM images confirmed that nonagglomerated TiO2 nanoparticles were highly dispersed inside the polymer matrices. We found that the concentration ratio of TiO2 to polymer in the precursor led to changes in precursor properties, such as permittivity and electrical conductivity, and resulted in changes in the produced particle size.
 ...
PMID:A new physical route to produce monodispersed microsphere nanoparticle-polymer composites. 1973 51

This paper focuses on the preparation and characterization of Poly(methyl methacrylate)/multi-walled carbon nanotube composites through ex-situ and in-situ processes. The extent of dispersion and fracture morphology was studied by TEM, AFM, SEM and FESEM. The increase in conductivity at percolated loading of 2.91 wt% was more for in-situ prepared PMMA/MWNTs nanocomposite as compared to ex-situ prepared nanocomposites. The dielectric constant of pure PMMA was increased from 5 to 72 in the ex-situ prepared PMMA/MWNTs nanocomposites with 4.76 wt% of MWNTs loading. Moreover, for the ex-situ nanocomposites containing 2.91 wt% of MWNTs, the dielectric constant was 15, but in-situ prepared PMMA/MWNTs nanocomposite showed two times increase at same loading of 2.91 wt% of MWNTs. Dielectric constant of PMMA/MWNTs nanocomposites loaded with (< 4.76 wt%) of MWNTs remained almost constant with frequency. Dynamic mechanical analysis showed remarkable increase in storage modulus, especially at higher temperatures with 4.76 wt% loading of carbon nanotubes as compared to pure PMMA. The presence of additional peak before T(g) indicated that CNTs could be used to wake up secondary relaxations, which were inactive in pure PMMA. Thermogravimetric analysis (TGA) showed that thermal stability of PMMA/MWNTs nanocomposites increased by 45 degrees C (in N2) and 27 degrees C (in air) at 4.76 wt% of MWNTs as compared to the pure PMMA.
 ...
PMID:Preparation and characterization of poly(methyl methacrylate)/multi-walled carbon nanotube composites. 1992 29

Poly(styrene-co-divinylbenzene) monolithic stationary phases have been synthesized for the first time by photoinitiated polymerization. An initiator composed of (+)-(S)-camphorquinone/ethyl-4-dimethylaminobenzoate/N-methoxy-4-phenylpyridinium tetrafluoroborate was activated using a 470 nm light emitting diode array as the light source. Spatially controlled polymerization of styrenic monoliths has been achieved within specific sections of a 100 microm id polytetrafluoroethylene-coated fused-silica capillary using simple photo masking. The sharpness of the edges was confirmed by optical microscopy, while SEM was used to verify a typical porous, globular morphology. Flow resistance data were used to assess the permeability of the monoliths and they were found to have good flow through properties with a flow resistance of 0.725 MPa/cm at 1 microL/min (water, 20 degrees C). Conductivity profiling along the length of the capillary was used to assess their lateral homogeneity. Monoliths which were axially rotated during polymerization were found to be homogeneous along the whole length of the capillary. The monolithic stationary phases were applied to the RP gradient separation of a mixture of proteins. Column fabrication showed excellent reproducibility with the retention factor (k) having a RSD value of 2.6% for the batch and less than 1.73% on individual columns.
 ...
PMID:Visible light initiated polymerization of styrenic monolithic stationary phases using 470 nm light emitting diode arrays. 2009 17

Poly-o-anisidine Sn(IV) arsenophosphate is a newly synthesized nanocomposite material and has been characterized on the basis of its chemical composition, ion exchange capacity, TGA-DTA, FTIR, X-RAY, SEM, and TEM studies. On the basis of distribution studies, the exchanger was found to be highly selective for lead that is an environmental pollutant. For the detection of lead in water a heterogeneous precipitate based ion-selective membrane electrode was developed by means of this composite cation exchanger as electroactive material. The membrane electrode is mechanically stable, with a quick response time, and can be operated over a wide pH range. The selectivity coefficients were determined by mixed solution method and revealed that the electrode is sensitive for Pb(II) in presence of interfering cations. The practical utility of this membrane electrode has been established by employing it as an indicator electrode in the potentiometric titration of Pb(II).
 ...
PMID:Synthesis and Characterization of Organic-Inorganic Nanocomposite Poly-o-anisidine Sn(IV) Arsenophosphate: Its Analytical Applications as Pb(II) Ion-Selective Membrane Electrode. 2014 82


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>