OBJECTIVE

To determine the efficacy and safety of intravitreal triamcinolone in chronic diffuse diabetic macular oedema.

METHODS

This prospective, interventional consecutive case series study consisted of 59 eyes (36 patients) with chronic diffuse diabetic macular oedema, which received an intravitreal injection of 4 mg triamcinolone acetonide. The results were evaluated by clinical examination and fluorescein angiography. Potential complications such as a rise in intraocular pressure, cataract progression and endophthalmitis were recorded.

RESULTS

All patients completed at least 6 months follow up. The mean visual acuity improved significantly from 0.17 +/- 3.4 to a maximum of 0.30 +/- 3.3 at the third postinjection month (P < 0.01). Mean improvements in visual acuity measured were 2.15 +/- 1.66, 2.42 +/- 2.66, 1.13 +/- 2.74, 0.96 +/- 2.01 and 0.08 +/- 2.34 lines at the 1, 3, 6, 9 and 12 months follow-up intervals, respectively. In all eyes in fluorescein angiography, macular oedema was resolved (63%) or decreased (37%) during the follow up. However, the macular oedema reached the pretreatment level in 29 (49%) of the eyes at 6 months and 15 of 21 eyes (71%) at 9 months after injection. Intraocular pressure exceeded 21 mmHg in 10 eyes, which were controlled by topical medication. Four eyes showed cataract progression. Endophthalmitis was not observed in any of the eyes.

CONCLUSIONS

Intravitreal injection of 4 mg triamcinolone acetonide appears to be an effective and relatively safe therapeutic method for diffuse diabetic macular oedema. Further studies are warranted to assess the long-term efficacy, safety and the need for reinjection.

BACKGROUND

To assess the need for, and the use of eye care services in older people seeking aged care.

METHODS

In total, 188 people (69.1% of those eligible) aged 65+ years who were assessed for aged care provision at Westmead Hospital, Sydney, were recruited in 2003 and re-examined a year later. At baseline, presenting visual acuity (VA) was randomly assessed in half the participants. People with under-corrected refractive error (pinhole VA improved at least 10 letters in those with presenting VA <6/6), bilateral visual impairment (better eye VA <6/12), or self-reported visual problems, were recommended to have further assessment by eye care professionals. At follow up, information on utilization of eye care services in the past 12 months was collected and VA was assessed in all returned participants.

RESULTS

Of the 188 baseline participants, 121 (70% of survivors) were revisited a year later. Overall, 90/121 participants (74%) had seen an eye care professional in the previous year. Of the 66 participants who were recommended to see an eye care professional, 42 (64%) were revisited and 37/42 (88%) complied with the recommendation. At revisit, bilateral visual impairment was found in 49/120 (41%). The proportion with bilateral visual impairment was lower in participants whose vision was assessed at baseline (35%) than in those whose vision was not assessed (47%, P = 0.17), and also lower among people who had visited an eye care professional during the previous 12 months (39%) than those who had not (45%, P = 0.57).

CONCLUSIONS

This pilot study indicates a relatively high need for, and high utilization of eye care services in the subgroup of older people seeking aged care services.

After 2 years of reviewing current research and studies on patient safety, the National Quality Forum released its evidence-based consensus report listing 30 "safe practices for better healthcare" at a meeting in Los Angeles. The forum's president and CEO, Kenneth Kizer, calls the report "basically a road map for safety" that can be used in not only hospitals but also other healthcare facilities such as nursing homes and ambulatory care settings.

Meiosis-activating sterol (MAS) has been shown to induce mouse oocytes cultured in the presence of hypoxanthine (HX) to resume meiosis. The present research was conducted to determine whether amphotericin B or ketoconazole (a promoter and an inhibitor of production of MAS), affected oocyte maturation. Mouse cumulus cell-enclosed oocytes (CEO) or denuded oocytes (DO) were cultured for 24 h in the presence of 4 mM HX with FSH or amphotericin B or ketoconazole. At the end of the culture, the frequency of germinal vesicle break down (GVBD) and polar body formation (PB) were recorded. The results demonstrated: (i) FSH (10-200 IU/l) induced dose-dependent oocytes maturation in CEO, but was without effect on DO. A maximum increase in GVBD and PB was observed with 25-50 IU/l FSH. The presence of FSH (50 IU/l) for 1 h was sufficient to induce meiotic resumption, which after 2 h reached a plateau similar to that of a continuous presence of FSH. (ii) CEO exposed to amphotericin B (0.0025-2.5 microg/l) underwent GVBD dose-dependently, whereas no effect was observed on DO. The presence of amphotericin B (0.025 microg/l) for 1 h stimulated oocyte resumption in a way similar to that of FSH. (iii) Amphotericin B (0.025 microg/l) and FSH (50 IU/l) did not show any additive effect on resumption of meiosis. (iv) Ketoconazole (10(-7)-10(-3) M) inhibited the effect of FSH on resumption of meiosis, but had no effect on oocyte spontaneous maturation. These results show that FSH and amphotericin B induce resumption of meiosis and indicate that they are likely to cause an accumulation of meiosis activating sterols in the CEO, but ketoconazole blocks the production of MAS. The present study supports the notion that MAS plays a physiological relevant role in triggering resumption of meiosis in mouse oocytes.

The role of the cumulus cells in initiating the resumption of meiosis after exposure to forskolin and dbcAMP was studied in the mouse. The resumption of meiosis was monitored by the percentage of germinal vesicle breakdown (GVBD) and polar body formation (PB). The cumulus-enclosed oocytes (CEO) and denuded oocytes (DO) were cultured with and without hypoxanthine (HX) in the culture medium. Three types of experiments were performed: (1) Effect of forskolin on spontaneous resumption of meiosis, i.e. cultures without HX, and two experiments in which HX is present throughout the culture: (2) Effect of transient exposure to forskolin or dibutyric-cyclic adenosinemonophosphate (dbcAMP) on GVBD prior to continued culture without forskolin or dbcAMP (oocyte priming). (3) Priming of CEO with forskolin for 2 hr, separation of cumulus cells and oocytes, followed by coculture of rejoined cumulus cells and oocytes, or coculture of the cumulus cells and new, unprimed DO. (1) Forskolin inhibited a spontaneous resumption of meiosis in a dose-dependent manner during the first 5 hr of culturing. After 22 hr all controls and CEO resumed meiosis, whereas only half of the DO did. (2) At least 1 hr of priming the CEO with forskolin is needed to induce GVBD and PB formation, but forskolin inhibited the resumption of meiosis when present for 24 hr. Similar results were obtained with a high concentration of dbcAMP. (3) A separation and rejoining of oocytes and cumulus cells after priming induced the resumption of meiosis in a significantly greater number of oocytes than in the control oocytes which were not primed.(ABSTRACT TRUNCATED AT 250 WORDS)

The present study was conducted to determine the effects of cumulus cells and sodium pyruvate during in vitro maturation of bovine oocytes on maturation, fertilization, and subsequent development. Cumulus-enclosed oocytes (CEOs) and cumulus-denuded oocytes (CDOs) were cultured for 24 h in polyvinylpyrrolidone-Hepes-tissue culture medium 199 with or without sodium pyruvate. Oocytes were fertilized in vitro and then cultured in CR1aa for 10 days. Before in vitro fertilization, the glutathione (GSH) content of some oocytes was measured. Maturation and normal fertilization rates of CDOs cultured with sodium pyruvate and CEOs were higher than that of CDOs cultured without sodium pyruvate. The CEOs showed significantly higher rates of development to the blastocyst stage than CDOs. The GSH contents of oocytes significantly decreased in CDOs after maturation culture, but the GSH contents of oocytes in CEOs remained at the same level as oocytes before culture. These results indicate that sodium pyruvate promotes nuclear maturation of bovine CDOs and that a continuing presence of cumulus cells during maturation is important for subsequent development of zygotes to the blastocyst stage. However, blastocysts produced from CDOs in the presence of sodium pyruvate showed a developmental competence to be normal calves, but it is not known if CDOs cultured without sodium pyruvate also were capable of developing into calves.

Due to their physicochemical characteristics, metal oxide nanoparticles (NPs) interact differently with cells compared to larger particles or soluble metals. Oxidative stress and cellular metal uptake were quantified in rat type II alveolar epithelial cells in culture exposed to three different NPs: manganese(II,III) oxide nanoparticles (Mn(3)O(4)-NPs), the soluble manganese sulfate (Mn-salt) at corresponding equivalent doses, titanium dioxide (TiO(2)-NPs) and cerium dioxide nanoparticles (CeO(2)-NPs). In the presence of reactive oxygen species an increased apoptosis rate was hypothesized. Oxidative stress was assessed by detection of fluorescently labeled reactive oxygen species and by measuring intracellular oxidized glutathione. Catalytic activity was determined by measuring catalyst-dependent oxidation of thiols (DTT-assay) in a cell free environment. Inductively coupled plasma mass spectrometry was used to quantify cellular metal uptake. Apoptosis rate was determined assessing the activity of caspase-3 and by fluorescence microscopic quantification of apoptotic nuclei. Reactive oxygen species were mainly generated in cells treated with Mn(3)O(4)-NPs. Only Mn(3)O(4)-NPs oxidized intracellular glutathione. Catalytic activity could be exclusively shown for Mn(3)O(4)-NPs. Cellular metal uptake was similar for all particles, whereas Mn-salt could hardly be detected within the cell. Apoptosis was induced by both, Mn(3)O(4)-NPs and Mn-salt. The combination of catalytic activity and capability of passing the cell membrane contributes to the toxicity of Mn(3)O(4)-NPs. Apoptosis of samples treated with Mn-salt is triggered by different, potentially extracellular mechanisms.

Fe(3)O(4)@SiO(2)@CeO(2) microspheres with magnetic core and mesoporous shell were synthesized, and the multifunctional materials were utilized to capture phosphopeptides and catalyze the dephosphorylation simultaneously, thereby labeling the phosphopeptides for rapid identification.

2-cyanoethylene oxide (CEO) is a direct-acting mutagen and the postulated proximate carcinogenic form of acrylonitrile (AN). We have studied the reactions of CEO with 2'-deoxyribonucleosides and in vitro with calf thymus DNA at pH 7.0-7.5 and 37 degrees C for 3 h. Reaction of CEO with dAdo gave 2 adducts, N6-(2-hydroxy-2-carboxyethyl)-dAdo (N6-HOCE-dAdo) (2% yield) and 1,N6-etheno-dAdo (epsilon-dAdo) (11%); reaction with dCyd resulted in the isolation of 3-HOCE-dUrd (22%); reaction with dGuo gave 7-(2-oxoethyl)-Gua (7-OXE-Gua) (31%) and reaction with dThd yielded 3-OXE-dThd (3%). Structural elucidation of adducts was accomplished by ultraviolet spectroscopy, high-field proton NMR spectroscopy and mass spectrometry. Structural confirmation was provided by an accurate mass measurement technique where diagnostic ions in the electron impact mass spectra of trimethylsilyl derivatives were measured to within 0.0007 atomic mass units. The facile Dimroth rearrangement of 1-HOCE-dAdo to N6-HOCE-dAdo and hydrolytic deamination of a dCyd adduct to 3-HOCE-dUrd is postulated to be catalyzed by the hydroxyl group on the 3-carbon side chain of the adduct. Reaction of CEO with calf thymus DNA yielded (nmol/mg DNA) N6-HOCE-dAdo (2); epsilon-dAdo (11); 3-HOCE-dUrd (80); 7-OXE-Gua (110) and 3-OXE-dThd (1). Thus CEO, like its metabolic precursor AN, directly alkylates DNA in vitro but at a much more rapid rate.

Chamomilla recutita (L.) Rauschert (Asteraceae), popularly known as chamomile, is a plant used in traditional medicine for various therapeutic purposes. Chamomile essential oil (CEO) is particularly known to inhibit the genotoxic damage produced by mutagens in mice somatic cells. The aim of this research was to determine the inhibitory potential of CEO on the genotoxic damage produced by daunorubicin (DAU) in mice germ cells. We evaluated the effect of 5, 50, and 500 mg/kg of essential oil on the rate of sister chromatid exchange (SCE) induced in spermatogonia by 10 mg/kg of the mutagen. We found no genotoxicity of CEO, but detected an inhibition of SCE after the damage induced by DAU; from the lowest to the highest dose of CEO we found an inhibition of 47.5%, 61.9%, and 93.5%, respectively. As a possible mechanism of action, the antioxidant capacity of CEO was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method and ferric thiocyanate assays. In the first test we observed a moderate scavenging potential of the oil; nevertheless, the second assay showed an antioxidant capacity similar to that observed with vitamin E. In conclusion, we found that CEO is an efficient chemoprotective agent against the damage induced by DAU in the precursor cells of the germinal line of mice, and that its antioxidant capacity may induce this effect.

The genomic sequences of low and high passages of the United States infectious laryngotracheitis (ILT) vaccine strains CEO and TCO were determined using hybrid next generation sequencing in order to define genomic changes associated with attenuation and reversion to virulence. Phylogenetic analysis of available full genomes grouped strains into three major clades: TCO, CEO, and Australian. Comparative genomics revealed that TCO attenuation is likely the result of an ORF C truncation. Genes involved in attenuation are generally clade-specific, however four genes ORF C, UL27, UL28 and UL39 commonly contained various mutations across the CEO and TCO lineages. The Thr644 mutation in the UL27 gene encoding glycoprotein B was identified in all virulent US strains. The US10 gene was identified as a potential virulence factor for the TCO revertant 81658. The UL41 gene was responsible for the robust gain in virulence of CEO-Fowl Laryngotracheitis(®) after 20 passages in chickens.

Ceria is an important component in three-way catalysts for the treatment of automobile exhaust gases owing to its ability to store and release oxygen, a property known as the oxygen storage capacity. Much effort has been focused on increasing the OSC of ceria, and one avenue of exploration is the ability to fabricate CeO(2)-based catalysts, which expose reactive surfaces. Here we show how models for a polycrystalline CeO(2) thin film, which expose the (111), (110), and dipolar (100) surfaces, can be synthesized. This is achieved by supporting the CeO(2) thin film on an yttrium-stabilized zirconia substrate using a simulated amorphization and recrystallization strategy. In particular, the methodology generates models which reveal the atomistic structures present on the surface of the reactive faces and provides details of the grain-boundary structures, defects (vacancies, substitutionals, and clustering), and epitaxial relationships. Such models are an important first step in understanding the active sites at the surface of a catalytic material.

Structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts have been investigated using X-ray diffraction (XRD), Raman spectroscopy, BET surface area, thermogravimetry, and high-resolution transmission electron microscopy (HREM). The effect of support oxides on the crystal modification of ceria cubic lattice was mainly focused. The investigated oxides were obtained by soft chemical routes with ultrahighly dilute solutions and were subjected to thermal treatments from 773 to 1073 K. The XRD results suggest that the CeO(2)-SiO(2) sample primarily consists of nanocrystalline CeO(2) on the amorphous SiO(2) surface. Both crystalline CeO(2) and TiO(2) anatase phases were noted in the case of CeO(2)-TiO(2) sample. Formation of cubic Ce(0.75)Zr(0.25)O(2) and Ce(0.6)Zr(0.4)O(2) (at 1073 K) were observed in the case of the CeO(2)-ZrO(2) sample. Raman measurements disclose the fluorite structure of ceria and the presence of oxygen vacancies/Ce(3+). The HREM results reveal well-dispersed CeO(2) nanocrystals over the amorphous SiO(2) matrix in the cases of CeO(2)-SiO(2), isolated CeO(2), and TiO(2) (anatase) nanocrystals, some overlapping regions in the case of CeO(2)-TiO(2), and nanosized CeO(2) and Ce-Zr oxides in the case of CeO(2)-ZrO(2) sample. The exact structural features of these crystals as determined by digital diffraction analysis of HREM experimental images reveal that the CeO(2) is mainly in cubic fluorite geometry. The oxygen storage capacity (OSC) as determined by thermogravimetry reveals that the OSC of the mixed oxide systems is more than that of pure CeO(2) and is system dependent.

Developing the triethylamine sensor with excellent sensitivity and selectivity is important for detecting the triethylamine concentration change in the environment. In this work, flower-like CeO₂-SnO₂ composites with different contents of CeO₂ were successfully synthesized by the one-step hydrothermal reaction. Some characterization methods were used to research the morphology and structure of the samples. Gas-sensing performance of the CeO₂-SnO₂ gas sensor was also studied and the results show that the flower-like CeO₂-SnO₂ composite showed an enhanced gas-sensing property to triethylamine compared to that of pure SnO₂. The response value of the 5 wt.% CeO₂ content composite based sensor to 200 ppm triethylamine under the optimum working temperature (310 °C) is approximately 3.8 times higher than pure SnO₂. In addition, CeO₂-SnO₂ composite is also significantly more selective for triethylamine than pure SnO₂ and has better linearity over a wide range of triethylamine concentrations. The improved gas-sensing mechanism of the composites toward triethylamine was also carefully discussed.

The MnO(x) and CeO(x) were in situ supported on carbon nanotubes (CNTs) by a poly(sodium 4-styrenesulfonate) assisted reflux route for the low-temperature selective catalytic reduction (SCR) of NO with NH(3). X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), H(2) temperature-programmed reduction (H(2)-TPR) and NH(3) temperature-programmed desorption (NH(3)-TPD) have been used to elucidate the structure and surface properties of the obtained catalysts. It was found that the in situ prepared catalyst exhibited the highest activity and the most extensive operating-temperature window, compared to the catalysts prepared by impregnation or mechanically mixed methods. The XRD and TEM results indicated that the manganese oxide and cerium oxide species had a good dispersion on the CNT surface. The XPS results demonstrated that the higher atomic concentration of Mn existed on the surface of CNTs and the more chemisorbed oxygen species exist. The H(2)-TPR results suggested that there was a strong interaction between the manganese oxide and cerium oxide on the surface of CNTs. The NH(3)-TPD results demonstrated that the catalysts presented a larger acid amount and stronger acid strength. In addition, the obtained catalysts exhibited much higher SO(2)-tolerance and improved the water-resistance as compared to that prepared by impregnation or mechanically mixed methods.

Small polaron carrier density in epitaxial, doped CeO(2) thin films under low oxygen partial pressure was determined from electrochemically-measured capacitance after accounting for interfacial effects and shown to agree well with bulk values.

BACKGROUND

To examine the relationship between socioeconomic factors, residential locality and cataract surgery incidence.

METHODS

This was a population-based study using the Western Australian Data Linkage System to identify all cataract operations performed in patients aged 50+ years in 1996 and 2001. Patients' residential addresses at the time of operation were geocoded to census localities. Using census-derived indices, procedures were categorized into socioeconomic groups and residential locations (metropolitan and rural). Poisson regression was used to analyse for differences in procedure rates.

RESULTS

The crude cataract surgery rate in Western Australia increased from 4458 to 6631 procedures per million person-years between 1996 and 2001. Female and older patients underwent more surgery. Metropolitan residents were more likely to undergo surgery compared with rural residents; a difference that increased by 17% between 1996 and 2001 (1996: incidence rate ratio [IRR] 1.07, 95% confidence interval [CI] 1.02-1.13; 2001: IRR 1.24, 95% CI 1.18-1.29). A pronounced 'U-shaped' pattern of difference had developed for socioeconomic disadvantage by 2001. The most advantaged underwent 9% more surgery than the most disadvantaged. Rates in the middle two groups were less than the lowest one.

CONCLUSIONS

There was growing inequity in the rates of cataract surgery for rural and poorer patients between 1996 and 2001. These differences partly reflect the increasingly two-tiered Australian health system with more privately provided cataract surgery in urban areas.

In this study we have examined the effects of denuded oocyte coculture with dissociated cumulus cells (CC) or intact oocyte-CC complexes on meiotic resumption. When denuded oocytes (DO) or cumulus cell-enclosed oocytes (CEO) were cultured in 40-microl drops of medium under oil, and held in meiotic arrest with 4 mM hypoxanthine plus 25 microM dbcAMP, they underwent germinal vesicle breakdown (GVB) at similar frequencies (34%-35%). Coculture of DO with complexes or dissociated CCs stimulated maturation (50% and 61% GVB, respectively), with no effect of DO on maturation of cocultured CEO (32% GVB). This coculture effect was increased with the number of CCs added to the culture drop. When either glucose or glutamine was eliminated from the medium, no meiotic induction resulted from cocultured CCs. When CEO were cultured alone in microdrops, increasing their number from 10 to 50 significantly lowered the percentage resuming maturation, an effect also reduced by removing glucose and/or glutamine from the medium. This effect was not observed with DO. When inhibitory medium was conditioned overnight with complexes, subsequent culture with DO led to higher maturation percentages than culture in unconditioned medium; however, when CEO were cultured in conditioned medium, there was either no effect or increased inhibition of maturation. Assay of glucose and pyruvate in spent medium showed that DO cultured alone consumed glucose and pyruvate, but under CC coculture conditions more glucose was consumed and significant amounts of pyruvate accumulated in the medium, changes that led to an increase in the maturation of DO. Further experiments showed that DO were more sensitive than CEO to the meiosis-inducing effect of pyruvate. These results demonstrate different responsiveness of DO and CEO to coculture conditions and question the physiological relevance of denuded oocyte/CC coculture to study meiotic induction.

The selection of culture media and supplements therein has a tremendous impact on the regulation of oocyte maturation in vitro. In the present study, we have evaluated how altering the levels of glutamine in the presence or absence of glucose affects meiotic arrest in cumulus cell-enclosed oocytes (CEO) and denuded oocytes (DO) when cultured in either the simple medium M16 or the more complex Eagle's minimum essential medium (MEM). We have also tested the effectiveness of follicle-stimulating hormone (FSH) in triggering germinal vesicle breakdown (GVB) and purine de novo synthesis in differing MEM culture conditions. When DO were cultured 17-18 hr in hypoxanthine (HX)- or dbcAMP-supplemented M16 medium, neither glucose nor glutamine had any effect on oocyte maturation, with dbcAMP the more effective inhibitor. In the absence of glutamine, cumulus cells promoted meiotic resumption, since significantly lower levels of meiotic arrest were maintained in CEO than in DO by either HX or dbcAMP, but addition of the amino acid dose-dependently decreased the maturation percentage in CEO below that observed in DO. In MEM, glutamine and glucose again had little effect on the maturation of DO, although the percentage of maturing DO in HX-supplemented medium was about 20% lower than that in M16 medium. In the absence of glucose, high levels of maturation were observed in CEO in glutamine-free medium that were dose-dependently lowered by the amino acid. However, when glucose was present, CEO were as effectively arrested as DO when glutamine was absent, with no further effect of the amino acid. This inhibitory action of glucose was dependent on the essential amino acids present in MEM. The effects of glutamine were not due to changes in metabolic coupling between the oocyte and cumulus cells. Measurement of purine de novo synthesis indicated that the maintenance of meiotic arrest as well as FSH induction of meiotic resumption were associated with increases in purine synthesis. We conclude that glucose and glutamine act cooperatively to promote the synthesis of new purine compounds within the somatic compartment and that the timing and duration of such synthesis determines whether meiotic resumption will be suppressed or promoted.

Microwave-based methods are widely employed to synthesize metal nanoparticles on various substrates. However, the detailed mechanism of formation of such hybrids has not been addressed. In this paper, we describe the thermodynamic and kinetic aspects of reduction of metal salts by ethylene glycol under microwave heating conditions. On the basis of this analysis, we identify the temperatures above which the reduction of the metal salt is thermodynamically favorable and temperatures above which the rates of homogeneous nucleation of the metal and the heterogeneous nucleation of the metal on supports are favored. We delineate different conditions which favor the heterogeneous nucleation of the metal on the supports over homogeneous nucleation in the solvent medium based on the dielectric loss parameters of the solvent and the support and the metal/solvent and metal/support interfacial energies. Contrary to current understanding, we show that metal particles can be selectively formed on the substrate even under situations where the temperature of the substrate is lower than that of the surrounding medium. The catalytic activity of the Pt/CeO(2) and Pt/TiO(2) hybrids synthesized by this method for H(2) combustion reaction shows that complete conversion is achieved at temperatures as low as 100 °C with Pt-CeO(2) catalyst and at 50 °C with Pt-TiO(2) catalyst. Our method thus opens up possibilities for rational synthesis of high-activity supported catalysts using a fast microwave-based reduction method.

Chloroethylene oxide (CEO), an ultimate carcinogenic metabolite of vinyl chloride, induces base-pair substitution mutations but not frameshift mutations in bacteria. The mutational specificity of CEO was investigated in Escherichia coli, using the trpA mutants developed by Yanofsky. Reversion frequencies to tryptophan prototrophy were analysed, and CEO was found to induce more GC----AT transitions than AT----TA transversions, in addition to a low frequency of other types of substitution. This specificity indicates that CEO is mutagenic through a miscoding DNA adduct. The results are discussed in relation to the various CEO-DNA adducts formed and to their reported or expected mispairing properties.

Ag@CeO2 nanocomposites were synthesized by a biogenic and green approach using electrochemically active biofilms (EABs) as a reducing tool. The as-synthesized Ag@CeO2 nanocomposites were characterized and used in antimicrobial, visible light photocatalytic and photoelectrode studies. The Ag@CeO2 nanocomposites showed effective and efficient bactericidal activities and survival test against Escherichia coli O157:H7, and Pseudomonas aeruginosa. The as-synthesized Ag@CeO2 nanocomposites also exhibited enhanced visible light photocatalytic degradation of 4-nitrophenol and methylene blue than pure CeO2. A photocatalytic investigation showed that the Ag@CeO2 nanocomposites possessed excellent visible light photocatalytic activities compared to pure CeO2. Electrochemical impedance spectroscopy and photocurrent measurements showed that the as-synthesized Ag@CeO2 nanocomposites exhibited excellent and enhanced responses to visible light irradiation. These results suggest that the AgNPs anchored at CeO2 induced visible light photoactivity by decreasing the recombination of photogenerated electrons and holes, and extending the response of pure CeO2 to visible light. Overall, as-synthesized Ag@CeO2 nanocomposites are smart materials that can be used for a range of applications, such as antimicrobial activity, visible light photocatalysis and photoelectrode.

A methodology is described for the preparation of Pd@CeO(2) core-shell nanostructures that are easily dispersible in common organic solvents. The method involves the synthesis of Pd nanoparticles protected by a monolayer of 11-mercaptoundecanoic acid (MUA). The carboxylic groups on the nanoparticle surfaces are used to direct the self-assembly of a cerium(IV) alkoxide around the metal particles, followed by the controlled hydrolysis to form CeO(2). The characterization of the nanostructures by means of different techniques, in particular by electron microscopy, allowed us to demonstrate the nature of core-shell systems, with CeO(2) nanocrystals forming a shell around the MUA-protected Pd core. Finally, an example of the use of these nanostructures as flexible precursors for the preparation of heterogeneous catalysts is reported by investigating the reactivity of Pd@CeO(2)/Al(2)O(3) nanocomposites toward CO oxidation, water-gas shift (WGS), and methanol steam reforming reactions. Together with CO adsorption data, these observations suggest the accessibility of the Pd phase in the nanocomposites.

To eliminate indoor formaldehyde (HCHO) pollution, Pd/CeO2 catalysts with different morphologies of ceria support were employed. The palladium nanoparticles loaded on {100}-faceted CeO2 nanocubes exhibited much higher activity than those loaded on {111}-faceted ceria nanooctahedrons and nanorods (enclosed by {100} and {111} facets). The HCHO could be fully converted into CO2 over the Pd/CeO2 nanocubes at a GHSV of 10,000 h(-1) and a HCHO inlet concentration of 600 ppm at ambient temperature. The prepared catalysts were characterized by a series of techniques. The HRTEM, ICP-MS and XRD results confirmed the exposed facets of the ceria and the sizes (1-2 nm) of the palladium nanoparticles with loading amounts close to 1%. According to the Pd 3d XPS and H2-TPR results, the status of the Pd-species was dependent on the morphologies of the supports. The {100} facets of ceria could maintain the metallic Pd species rather than the {111} facets, which promoted HCHO catalytic combustion. The Raman and O 1s XPS results revealed that the nanorods with more defect sites and oxygen vacancies were responsible for the easy oxidation of the Pd-species and low catalytic activity.