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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Attenuation of the increase in blood flow caused by acetylcholine in the peripheral vasculature and coronary circulation of patients with heart failure has been interpreted as an impairment of endothelium-dependent vasodilation. The aim of this study was to compare in man the effects of acetylcholine, which also has endothelium-independent actions, with substance P, which appears to be a pure endothelium-dependent vasodilator, on epicardial and resistance coronary arteries in patients with idiopathic dilated cardiomyopathy. The effects of intracoronary acetylcholine (10(-7) M and 10(-6) M) and substance P (5, 10 and 25 pmol.min-1) on epicardial coronary artery diameter and coronary blood flow velocity were measured with an intracoronary Doppler flow probe and quantitative coronary angiography in 11 patients with idiopathic dilated cardiomyopathy and 10 control subjects. Epicardial coronary artery diameter did not change with acetylcholine but increased significantly with substance P in both groups (cardiomyopathy patients: 3.3 +/- 0.2 mm (mean +/- SEM) at baseline vs 3.9 +/- 0.2 mm with substance P25 pmol.min-1, P < 0.01; controls: 3.1 +/- 0.2 mm at baseline vs 3.9 +/- 0.3 mm with substance P25 pmol.min-1, P < 0.05). Coronary flow ratios with acetylcholine were lower in cardiomyopathy patients (10(-7) M: 1.4 +/- 0.1 vs 2.3 +/- 0.4, P = 0.05; 10(-6) M: 1.8 +/- 0.2 vs 3.2 +/- 0.5, P = 0.05 vs controls).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effects of intracoronary substance P and acetylcholine on coronary blood flow in patients with idiopathic dilated cardiomyopathy. 753 Jun 61

The long-term pulmonary consequences of right middle lobe syndrome (RMLS) in childhood are not known. Therefore, outcome was evaluated in 17 children with RMLS diagnosed in early childhood (mean age, 3.3 years; SD, 1.1 year). Mean age at follow-up was 10.1 years (SD, 2.6 years). RMLS was defined as atelectasis of the right middle lobe (RML) of at least 1 month's duration and visible on the lateral view of the chest radiograph as a wedge-shaped density extending from the hilum anteriorly and downward. Seventeen children without personal history of allergy or respiratory tract disease were studied as control group. Five of 17 study group children had ongoing respiratory problems: symptoms of asthma were present in 4 patients, and cylindrical bronchiectasis was present in one patient. Chest radiograph at follow-up was abnormal in six patients. Pulmonary function tests, including mean and SEM for vital capacity (VC) (82% of predicted +/- 7 vs 94% predicted +/- 3), FEV1 (77% of predicted +/- 12 vs 96% of predicted +/- 4) and their ratio (75 +/- 5 vs 85 +/- 3) were significantly lower in patients with ongoing respiratory symptoms than in the control children. The provocative dose causing a 20% decrease in FEV1 (PD20) of methacholine was significantly lower in patients with ongoing symptoms at follow-up than in control children and in patients without symptoms at follow-up (2.8[2.2 to 3.1] vs 4.5[2.2 to 8.8] and 9.2[2.3 to 24] mg/mL; median and P25-75, p < 0.05). Age at initial diagnosis tended to be younger in patients with ongoing symptoms at follow-up (2.3 +/- 0.7 years vs 3.8 +/- 0.4 years; p < 0.08).
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PMID:Outcome after right middle lobe syndrome. 760 50

Ontogenesis of both vagal control of heart rate and the baroreceptor vagal reflex were evaluated in rats at postnatal ages (P) of 5/6, 10, 15, 20, 25 and >>42 days anaesthetised with urethane (1.5 g/kg). Between P5/6 and P25 heart rate rose from 372 +/- 12 to 448 +/- 20 beats per minute and mean arterial pressure increased from 33.9 +/- 3.1 to 74.59 +/- 3.25 mm Hg (mean +/- SEM, n = 7 and 11 respectively). Cardiac vagal tone was absent at P10 but significant at P20 (P < 0.05) as revealed with atropine (0.5-1 mg/kg i.v.). Baroreceptor cardiac reflex sensitivity, tested with phenylephrine (10-50 microg/kg i.v.), was attenuated significantly in P10-20 rats compared with P5/6, P25 and mature animals. In P14-17 rats stimulation of neurones in either the solitary tract or ambiguual nuclei, by microinjection of L-glutamate (100-200 pmol), evoked an atropine-sensitive bradycardia indicating a functional integrity of central and peripheral efferent pathways mediating the baroreceptor reflex. Thus, the baroreceptor vagal reflex is functional in P5/6 rats but becomes attenuated between P10-P20, which is coincident with the maturational rise in arterial pressure.
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PMID:Changes in baroreceptor vagal reflex performance in the developing rat. 921 10

The preparation and characterization of thick (9 microns), clear, mechanically robust and photocatalytically active films of nanocrystalline anatase titania are described. XRD and SEM analysis show the films comprise 13 nm particles of anatase TiO2. Thin (54 nm) films of the 'paste' TiO2, along with sol-gel titania films made by a more traditional route are also prepared and characterised. All titania films mediate the photocatalytic destruction of stearic acid with a quantum yield of 0.0016 +/- 0.0003, using either 365 nm (i.e. BLB) or 254 nm (germicidal) light. P25 TiO2 films also appear to mediate the same process with a similar formal quantum efficiency. Of all the films tested, the thick paste TiO2 films are the most ideally suited for use with near UV light, for reasons which are discussed. All the titania films tested exhibit photoinduced superhydrophilicity.
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PMID:Preparation and characterisation of novel thick sol-gel titania film photocatalysts. 1280 83

The immobilized photocatalyst, P25 supported by glass fiber, was prepared by calcining method. The effect of calcining temperature on the photocatalytic activity and the effect of initial pH and inorganic anions on the photocatalytic degradation of Reactive Red X-3B were explored in a new photocatalytic contact oxidation reactor. The results show that catalyst activity is affected drastically by calcining temperature, the optimal temperature is 300 degrees C; the SEM photos of immobilized catalyst indicated that P25 adhered to glass fiber firmly; The Reactive Red X-3B was more easily degraded in acid solution, when initial pH increasing from 2.0 to 10.0, the degradation rate of Reactive Red X-3B decreased from 90.06% to 42.71%; inorganic anions, CO3(2-) and SO4(2-), had little effect on the degradation of Reactive Red X-3B. However, the degradation of Reactive Red X-3B significantly decreased, 17.03% down, in the presence of Cl-. So it was a good alternate scenario to conduct photocatalytic oxidation by using immobilized P25 in a contact oxidation reactor.
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PMID:[Photocatalytic degradation of reactive red X-3B by immobilized P25 in a contact oxidation reactor]. 1636 83

A new titanium(IV) oxide-hectorite nanofilm photocatalyst was prepared on quartz slides. It was evaluated in the photooxidation of dibenzothiophene (DBT) in nonpolar organic solution (tetradecane), as a model for diesel fuel. A removal regimen was developed consisting of catalytic photooxidation followed by adsorption of products on silica gel. Photooxidation of DBT was performed with and without catalyst, at 254 and 300 nm. Comparison was made with a commercially available TiO(2) catalyst, Degussa P25. The catalyst was analyzed by nitrogen adsorption, XRD, SEM, and TGA-DTA. DBT concentrations were measured by HPLC and UV spectrophotometry. Preliminary qualititative analysis of products was performed by UV and HPLC. Results indicated that the outlined process was effective in reducing sulfur levels to below 10 ppm sulfur.
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PMID:Photooxidation of dibenzothiophene on TiO(2)/hectorite thin films layered catalyst. 1660 Feb 76

Nitrogen doped titania was prepared by low temperature sol-gel method using titanium precursor and nitrogen containing bases like triethylamine and tetramethyl ammonium hydroxide compounds. The materials were characterized by XRD, BET, SEM, XPS, DRS-UV, and FT-IR techniques. DRS-UV study substantially indicates shift of the absorption edge of TiO2 to lower energy region. The phase composition, crystallinity, specific surface area, and visible light activity of nitrogen doped titania depend upon the preparation conditions. Photocatalytic degradation of bisphenol-A in aqueous medium was investigated by TiO2 and nitrogen doped TiO2 under visible light irradiation in a batch photocatalytic reactor. The results indicate higher visible light activity for nitrogen doped TiO2 than commercial TiO2 (Degussa P25) for bisphenol-A degradation. The influence of various parameters such as initial concentration of bisphenol-A, catalyst loading and pH was examined for maximum degradation efficiency.
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PMID:Visible light active photocatalytic degradation of bisphenol-A using nitrogen doped TiO2. 1703 63

Mesoporous titania nanorod/titanate nanotube composites were prepared using TiF4 and H(3)BO(3) as the precursors. The prepared samples were characterized with TEM, SEM, XRD, HRTEM, and nitrogen adsorption-desorption isotherms. The photocatalytic activities were evaluated by photocatalytic oxidation of acetone in a gas phase and photocatalytic discolorization of methyl orange aqueous solution in an aqueous phase, respectively. The results indicated that the photocatalytic activity of the mesoporous titania nanorod/titanate nanotube composites exceeded that of P25 by a factor of about 2.5 times for the photocatalytic oxidation of acetone. This could be attributed to the fact that the former had a larger specific surface area and a higher pore volume. Moreover, the mesoporous titania nanorod/titanate nanotube composites, which could be readily separated after photocatalytic reaction in an aqueous phase, exhibited highly photocatalytic activity for the degradation of methyl orange aqueous solution.
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PMID:Synthesis, characterization and photocatalytic activity of mesoporous titania nanorod/titanate nanotube composites. 1729 35

Characterizations of microwave-induced titanate nanotubes (NaxH(2-x)Ti3O7, TNTs) were conducted by the determinations of specific surface area (S(BET)), X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS), ionic coupled plasma-atomic emission spectrometry(ICP-AES), scanning electron microscopy/ energy dispersive X-ray (SEM/EDX), and high-resolution transmission electron microscopy (HR-TEM). The applied level of microwave irradiation during the fabrication process is responsible for both the intercalation intensity of Na atoms into TNTs and the type of crystallization phase within TNTs, which dominate the efficiency of photocatalytic NH3/NH4+. A pure TNT phase presents no powerful ability toward photocatalytic NH3/ NH4+, while the photocatalytic efficiency can be enhanced with the presence of a rutile phase within TNTs. In addition, the mixture of anatase and rutile phase within P25 TiO2 prefers forming NO3-, whereas TNTs yield higher NO2- amount Regarding the effect of acid-washing treatment on TNTs, the acid-treated TNTs with enhanced ion exchangeability considerably improve the NH3/NH4+ degradation and NO2-/NO3- yields. This result is likely ascribed to the easy intercalation of NH3/ NH4+ into the structure of acid-washing TNTs so that the photocatalytic oxidation of intercalated NH3/NH4+ is not limited to the shielding effect resulting from the overload of TNTs.
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PMID:Photocatalytic oxidation of aqueous ammonia over microwave-induced titanate nanotubes. 1860 78

C.I. Basic Red 46, commonly used as a textile dye, was photocatalytically removed using supported TiO2 nanoparticles irradiated by a 30 W UV-C lamp in a batch reactor. The investigated photocatalyst was industrial Degussa P25 (crystallite mean size 21 nm) immobilized on glass beads by a heat attachment method. The catalyst was characterized by XRD, SEM, TEM and BET techniques. The process of the dye decolorization in the presence of TiO2 nanoparticles was experimentally studied through changing the initial dye concentration, UV light intensity and initial pH. The influence of inorganic anions such as chloride, sulphate, bicarbonate, carbonate and phosphate on the photocatalytic decolorization of BR46 was investigated. The decolorization of BR46 follows the pseudo-first-order kinetic according to the Langmuir-Hinshelwood model (k1 = 0.273 mg L(-1) min(-1), 2 = 0.313 (mg L(-1))(-1)). The efficiency parameters such as apparent quantum yield and electrical energy per order (EEO) were estimated. An artificial neural network model (ANN) was developed to predict the photocatalytic decolorization of BR46 solution. The findings indicated that the ANN provided reasonable predictive performance (R2 = 0.96). The influence of each parameter on the variable studied was assessed: initial concentration of the dye being the most significant factor, followed by the initial pH and reaction time.
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PMID:Photocatalytic removal of C.I. Basic Red 46 on immobilized TiO2 nanoparticles: artificial neural network modelling. 1994 46


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