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)

The chitosan only, chitosan/Pluronic F68, chitosan/gelatin, chitosan/Pluronic F68/gelatin microparticles and betamethasone-loaded chitosan/Pluronic F68/gelatin microparticles were successfully prepared by a spray-drying method. Microparticle characteristics (yield rate, zeta potential, particle size and tap density), loading efficiencies, microparticle morphology and in-vitro release properties were investigated. By properly choosing excipient type, concentration and varying the spray-drying parameters, a high degree of control was achieved over the physical properties of the dry chitosan powders. SEM micrograph shows that the particle sizes of the varied chitosan composed microparticles ranged from 2.12-5.67 microm and the external surfaces appear smooth. Using betamethasone as model drug, the spray-drying is a promising way to produce good spherical and smooth surface microparticles with a narrow particle size range for controlled delivery of betamethasone. The positively charged betamethasone-loaded microparticles entrapped in the chitosan/Pluronic F68/gelatin microparticles with trapping efficiencies up to 94.5%, yield rate 42.5% and mean particle size 5.64 microm varied between 4.32-6.20 microm and tap densities 0.128 g/cm(3). The pH of particle was increased with increasing betamethasone-loaded amount, but both zeta potential and tap density of the particles decreased with increasing betamethasone-loaded amount. The betamethasone release rates from chitosan/Pluronic F68/gelatin microparticles were influenced by the drug/polymer ratio in the manner that an increase in the release% and burst release% was observed when the drug loading was decreased. The in vitro release of betamethasone showed a dose-dependent burst followed by a slower release phase that was proportional to the drug concentration in the concentration range between 14-44%w/w.
 ...
PMID:Optimizing formulation factors in preparing chitosan microparticles by spray-drying method. 1255 78

Renin-angiotensin-aldosterone system blockade has been shown to protect against renal damage in salt-supplemented, stroke-prone spontaneously hypertensive rats (SHRsp). Based on intermittent tail-cuff blood pressure (BP) measurements, it has been claimed that such protection is BP-independent and mediated by a blockade of the direct tissue-damaging effects of angiotensin and/or aldosterone. BP radiotelemetry was performed for 8 weeks in approximately 10-week-old male SHRsp who received a standard diet and either tap water (n=10) or 1% NaCl to drink. Saline-drinking SHRsp were either left untreated (n=12), received enalapril (50 mg/L) in drinking fluid (n=9), or had subcutaneous implantation of time-release 200-mg pellets of aldactone (n=10). The average systolic BP (mean+/-SEM) during the final 3 weeks was significantly higher (P<0.05) in untreated saline-drinking (215+/-6 mm Hg) SHRsp but not aldactone-treated (198+/-4 mm Hg) or enalapril-treated treated SHRsp (173+/-1 mm Hg), as compared with tap water-drinking SHRsp (197+/-3 mm Hg). Histological renal damage scores at 8 weeks paralleled the BP in all groups, with an excellent correlation (r=0.8, P<0.001, n=41). Moreover, a renal damage score of >5 was only observed in SHRsp whose average systolic BP during the final 3 weeks exceeded 200 mm Hg, indicating a threshold relation with BP. These data show that protection by renin-angiotensin-aldosterone system blockade in this model is BP-dependent and mediated by preventing the severe increases in BP seen in untreated salt-supplemented SHRsp and further underscore the limitations of interpretations based on conventional tail-cuff BP measurements.
 ...
PMID:Renoprotection by ACE inhibition or aldosterone blockade is blood pressure-dependent. 1257 79

An EDTA bonded conducting polymer modified electrode (EDTA-CPME) was fabricated by polymerization of 3',4'-diamino-2,2';5',2''-terthiophene monomer on a GCE, followed by the reaction with EDTA in the presence of catalyst. The surface of the resulting modified electrode was characterized with EQCM, ESCA, SEM, Auger electron spectroscopy, scanning Auger microscopy, and electrochemical methods. The amounts of polymer and EDTA attached on the polymer film were determined. Simple immersing of the EDTA-CPME into a sample solution led to the chemical deposition through the complexation with Pb2+, Cu2+, and Hg2+ ions, simultaniously. Various experimental parameters that affect the simultaneous analysis of the metal ions, e.g., EDTA amount, pH, deposition time, and deposition temperature, were optimized. Calibration plots for the EDTA-CPME with square wave voltammetry were obtained in the concentration range between 5.0 x 10(-10) and 1.0 x 10(-7) M for Cu(II) and between 7.5 x 10(-10) and 1.0 x 10(-7) M for Pb(II) and Hg(II). The detection limits for Pb(II), Cu(II), and Hg(II) ions were determined to be about 6.0 x 10(-10), 2.0 x 10(-10), and 5.0 x 10(-10) M, respectively. Interference effects from other metal ions were studied at various pHs and it was found that there was little or no effect on the simultaneous determination. The stability of the EDTA-CPME was remarkably improved by coating the surface with the Nafion film, and the electrode can be used for more than one month. Analytical availability of the EDTA-CPME was demonstrated by the application for the certified standard urine reference material and tap water.
 ...
PMID:Characterization of an EDTA bonded conducting polymer modified electrode: its application for the simultaneous determination of heavy metal ions. 1264 Dec 32

Metal nanoparticles (Pt, Au, or Cu) together with multiwalled and single-walled carbon nanotubes (MWCNT and SWCNT) solubilized in Nafion have been used to form nanocomposites for electrochemical detection of trinitrotoluene (TNT) and several other nitroaromatics. Electrochemical and surface characterization by cyclic voltammetry, AFM, TEM, SEM, and Raman spectroscopy confirmed the presence of metal nanoparticles on CNTs. Among various combinations tested, the most synergistic signal effect was observed for the nanocomposite modified glassy carbon electrode (GC) containing Cu nanoparticles and SWCNT solubilized in Nafion. This combination provided the best sensitivity for detecting TNT and other nitroaromatic compounds. Adsorptive stripping voltammetry for TNT resulted in a detection limit of 1 ppb, with linearity up to 3 orders of magnitude. Selectivity toward the number and position of the nitro groups in different nitroaromatics was very reproducible and distinct. Reproducibility of the TNT signal was within 7% (n = 8) from one electrode preparation to another, and the response signal was stable (+/-3.8% at 95% confidence interval) for 40 repeated analyses with 10 min of preconditioning. The Cu-SWCNT-modified GC electrode was demonstrated for analysis of TNT in tap water, river water, and contaminated soil.
 ...
PMID:Metallic nanoparticle-carbon nanotube composites for electrochemical determination of explosive nitroaromatic compounds. 1687 89

Iridium-modified, boron-doped diamond electrodes fabricated by an ion implantation method have been developed for electrochemical detection of arsenite (As(III)). Ir+ ions were implanted with an energy of 800 keV and a dose of 10(15) ion cm(-2). An annealing treatment at 850 degrees C for 45 min in H2 plasma (80 Torr) was required to rearrange metastable diamond produced by an implantation process. Characterization was investigated by SEM, AFM, Raman, and X-ray photoelectron spectroscopy. Cyclic voltammetry and flow injection analysis with amperometric detection were used to study the electrochemical reaction. The electrodes exhibited high catalytic activity toward As(III) oxidation with the detection limit (S/N = 3), sensitivity, and linearity of 20 nM (1.5 ppb), 93 nA microM(-1) cm(-2), and 0.999, respectively. The precision for 10 replicate determinations of 50 microM As(III) was 4.56% relative standard deviation. The advantageous properties of the electrodes were its inherent stability with a very low background current. The electrode was applicable for analysis of spiked arsenic in tap water containing a significant amount of various ion elements. The results indicate that the metal-implanted method could be promising for controlling the electrochemical properties of diamond electrodes.
 ...
PMID:Electrochemical detection of arsenic(III) using iridium-implanted boron-doped diamond electrodes. 1697 Mar

Boron doped diamond (BDD) macro- and microelectrodes were modified by electrodeposition of platinum nanoparticles using a multipotential step electrodeposition technique and used for the oxidative determination of arsenite, As(III). The formation of Pt nanoparticles was evident from cyclic voltammetry measurement, whereas AFM and SEM revealed the size and size distribution of deposited Pt nanoparticles. Raman spectroscopy illustrated a correlation between the typical BDD signature and the number of platinum deposition cycles. Linear sweep voltammetry performed with the modified BDD microelectrode outperformed its macrocounterpart and resulted in very low detecting currents with enhanced signal-to-noise ratios. With linearity up to 100 ppb and a detection limit of 0.5 ppb, the electrochemical system was applicable for processing tap and river water samples. Over 150 repetitive runs could be performed, and electrochemical etching of platinum allowed the reuse of the BDD microelectrode. The presence of copper and chloride ions, the two most severe interferents at levels commonly found in groundwater, did not interfere with the assay.
 ...
PMID:Reusable platinum nanoparticle modified boron doped diamond microelectrodes for oxidative determination of arsenite. 1722 13

The morphology and elemental composition of the corrosion products of copper teapot's inner-surface were characterized by the scanning electron microscopy and energy dispersive X-ray surface analysis (SEM/EDS), X-ray powder diffraction (XRD) and X-ray photon spectroscopy (XPS) analysis. It was revealed that Cu, Fe, Ca, P, Si and Al were the main elements of corrosion by-products, and the alpha-SiO(2), Cu(2)O and CaCO(3) as the main mineral components on the inner-surface of copper teapot. The effects of organic matters coming from Chinese tea on soluble copper release from copper teapots in tap water were also investigated. The results showed that the doses of organic matter (as TOC), temperate and stagnation time have significant effects on the concentration of soluble copper released from copper teapots in tap water.
 ...
PMID:Effects of organic matters coming from Chinese tea on soluble copper release from copper teapot. 1790 99

Electrocoagulation (EC) is a promising electrochemical technique for water treatment. In this work electrocoagulation (with aluminum as electrodes) was studied for iron Fe(II) removal from aqueous medium. Different concentration of Fe(II) solution in tap water was considered for the experiment. During EC process, various amorphous aluminum hydroxides complexes with high sorption capacity were formed. The removal of Fe(II) was consisted of two principal steps; (a) oxidation of Fe(II) to Fe(III) and (b) subsequent removal of Fe(III) by the freshly formed aluminum hydroxides complexes by adsorption/surface complexation followed by precipitation. Experiments were carried out with different current densities ranging from 0.01 to 0.04 A/m2. It was observed that the removal of Fe(II) increases with current densities. Inter electrode distance was varied from 0.005 to 0.02 m and was found that least inter electrode distance is suitable in order to achieve higher Fe(II) removal. Other parameters such as conductivity, pH and salt concentration were kept constant as per tap water quality. Satisfactory iron removal of around 99.2% was obtained at the end of 35 min of operation from the initial concentration of 25 mg/L Fe(II). Iron concentration in the solution was determined using Atomic absorption spectrophotometer. By products obtained from the electrocoagulation bath were analyzed by SEM image and corresponding elemental analysis (EDAX). Cost estimation for the electrocoagulation was adopted and explained well. Up to 15 mg/L of initial Fe(II) concentration, the optimum total cost was 6.05 US$/m3. The EC process for removing Fe(II) from tap water is expected to be adaptable for household use.
 ...
PMID:Removal of Fe(II) from tap water by electrocoagulation technique. 1816 28

We have combined the therapeutic potential of nanoparticles systems with the ease of manipulation of microparticles by developing a hybrid vector named Trojan particles. We aim to use this new delivery vehicle for intravitreal administration of dexamethasone. Initialy, dexamethasone acetate (DXA) encapsulation into biodegradable poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was optimized. Then, Trojan particles were formulated by spray drying 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC), hyaluronic acid (HA) and different concentrations of nanoparticle suspensions. The effect of nanoparticles concentration on Trojan particle physical characteristics was investigated as well as the effect of the spray drying process on nanoparticles size. Finally, DXA in vitro release from nanoparticles and Trojan particles was evaluated under sink condition. SEM and confocal microscopy show that most of Trojan particles are spherical, hollow and possess an irregular surface due to the presence of nanoparticles. Neither Trojan particle tap density nor size distribution are significantly modified as a function of nanoparticles concentration. The mean nanoparticles size increase significantly after spray drying. Finally, the in vitro release of DXA shows that the excipient matrix provides protection to encapsulated nanoparticles by slowing drug release.
 ...
PMID:Dexamethasone acetate encapsulation into Trojan particles. 1837 42

The present study was designed to investigate whether maternal consumption of aqueous extract of Hibiscus sabdariffa (HS) during lactation will affect the postnatal growth and onset of puberty in the female offspring. Eighteen in-bred virgin female Sprague-Dawley rats aged between 10-12 weeks and weighing 125 +/- 5.5g (mean +/- SEM) with two consecutive regular 4-day estrus cycles were randomly assigned to one of three groups of 6 rats per group. One group had tap water (Control); another had 0.6g/100ml while the third group had 1.8g/100ml in their drinking water throughout lactation (21 days). Results showed that HS consumption during lactation significantly (P < 0.05) decreased maternal fluid and food intake, increased postnatal weight gain and delays the onset of puberty in the female offspring.
 ...
PMID:Maternal consumption of an aqueous extract of Hibiscus sabdariffa during lactation accelerates postnatal weight and delays onset of puberty in female offspring. 1943 21


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