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71.
72.
Livraghi S Corazzari I Paganini MC Ceccone G Giamello E Fubini B Fenoglio I 《Chemical communications (Cambridge, England)》2010,46(44):8478-8480
A safe UV filter may be obtained by inhibiting the photo-generation of free radicals through modification of the surface of TiO(2) nanoparticles with carbon. 相似文献
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The cerebral involvement of a 13-yr-old boy with Wilson's disease was serially evaluated during the first 18 mo of D-penicillamine treatment. An ultra-low-field magnetic resonance imaging (ULF MRI) system, operating at 0.02 T, with computerized image processing was used. The half-yr period prior to the clinical diagnosis was set, the patient had showed poor school performance, emotional lability, deteriorating handwriting, progressively slow, gross, and fine motor functions, and a fixed rigid smile. No overt signs of liver disease were found. With D-penicillamine treatment (1–1.5 g/d) a continuous improvement was seen. The pretreatment MRI investigation showed pronounced pathological transformation in the basal ganglia. However, changes were seen also in most other parts of the brain indicating diffuse involvement. During treatment the computerized MR images became gradually more normal. The current magnetic resonance imaging system with computerized image processing is a sensitive and simple method for evaluation of subtle parenchymal changes of the brain. 相似文献
76.
In the eighties, Iwahara discovered that doped Sr and Ba cerates show significant proton conduction, at high temperature,
and in hydrogen- or water-containing atmosphere [1]. Begin ‘90 it was proved that also doped zirconates (Sr, Ba, Ca) join
this family of proton conducting perovskites [2]. Within this group, indium doped CaZrO3 is one of the more interesting materials for applications, being mechanically and chemically particularly stable, and producible
in very dense form. Specifically, it was already succesfully incorporated in a hydrogen sensor for liquid aluminium [3]. In
principle, this sensor works as a simple electrochemical hydrogen concentration cell described by Nernst. However, as already
remarked phenomenologically from the beginning [1], a hydrogen concentration cell using these perovskites shows the theoretically
predicted emf, only in the presence of humidity. In this paper we want to go deeper into the reasons for this phenomenon.
Paper presented at the 2nd Euroconference on Solid State Ionics, Funchal, Madeira, Portugal, Sept. 10–16, 1995 相似文献
77.
Carlos Camacho‐Camacho Monique Biesemans Ingrid Verbruggen Rudolph Willem 《应用有机金属化学》2005,19(3):343-346
The reactivity and catalytic potential of the tin salicylaldoximate cluster [(Me2Sn)2(Me2SnO)(OCH3) (HONZO)(ONZO)] ( 1 ), with HONZOH = o‐HON?CH? C6H4OH, on the acylation reaction of various alcohols with ethyl acetate is reported. The catalyst is active toward primary and unhindered secondary alcohols, but inefficient toward tertiary and secondary bulky alcohols and phenols. A possible mechanism for the transesterification reaction catalyzed by 1 , accounting for the influence of steric factors, is proposed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
78.
Root bark of Berberis hispanica Boiss. & Reut. constitutes an important source of alkaloids and is traditionally used in Algeria and Morocco in many herbal formulations particularly for the treatment of stomach infections and colon cancer. Activity-guided fractionation of Berberis extract is developed by step-gradient elution on column chromatography followed by preparative HPLC to isolate the most antistaphylococcal compound. Solvent extraction-activity screening indicates that ethanol should be used as the extracting solvent as it has exhibited the highest activity against Staphylococcus aureus(Rosenbach ATCC6538) followed by water extract, whereas no activity is recorded for acetone and hexane extracts. Screening of collected fractions from chromatographic separations indicates that the fraction presenting the highest antistaphylococcal activity is identified as berberine tannate by UV spectrum, melting point measurement and confirmed by liquid chromatography coupled to mass spectrometry (LC/MS). The minimal inhibition concentration value of berberine tannate against S. aureus is evaluated at 5?µg?mL?1. 相似文献
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Helicobacter species have been isolated and cultured from both the gastric and enterohepatic niches of the gastrointestinal tract and
are associated with a wide spectrum of diseases. Some members of the enterohepatic Helicobacter species (EHS), which include Helicobacter bilis, Helicobacter hepaticus and Helicobacter pullorum, are associated with chronic inflammatory and proliferative bowel inflammation, hepatitis and in experimental murine studies
with hepatic cancer. The present study aimed to explore if polysulphated polysaccharides can prevent adhesion of EHS to the
murine macrophage cell line J774A.1. A competitive binding assay showed that heparin and heparan sulphate at a concentration
of 1.25 mg/ml reduced binding of H. hepaticus and H. pullorum to the host cells, but not H. bilis. Of the tested Helicobacter spp, the highest inhibition by heparin was demonstrated for H. pullorum (P < 0.01), the most hydrophilic strain. Partially or completely de-sulphated heparin derivatives lost the ability to inhibit
adherence of EHS, indicating the importance of sulphated groups of heparin. The most efficient inhibitor of EHS binding to
macrophages was fucoidan, which reduced bacterial adhesion of the three enterohepatic Helicobacter species to a greater extent than heparin, 60–90% inhibition vs 30–70% inhibition by heparin. Identification of receptors
that EHS ligands bind to is important for understanding the development of infection and may provide a rational target to
prevent infection and therapy. 相似文献