Showing papers by "University of Ioannina published in 2004"

TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations A review

Abstract: The photocatalytic degradation of azo dyes containing different functionalities has been reviewed using TiO2 as photocatalyst in aqueous solution under solar and UV irradiation. The mechanism of the photodegradation depends on the radiation used. Charge injection mechanism takes place under visible radiation whereas charge separation occurred under UV light radiation. The process is monitored by following either the decolorization rate and the formation of its end-products. Kinetic analyses indicate that the photodegradation rates of azo dyes can usually be approximated as pseudo-first-order kinetics for both degradation mechanisms, according to the Langmuir–Hinshelwood model. The degradation of dyes depend on several parameters such as pH, catalyst concentration, substrate concentration and the presence of electron acceptors such as hydrogen peroxide and ammonium persulphate besides molecular oxygen. The presence of other substances such as inorganic ions, humic acids and solvents commonly found in textile effluents is also discussed. The photocatalyzed degradation of pesticides does not occur instantaneously to form carbon dioxide, but through the formation of long-lived intermediate species. Thus, the study focuses also on the determination of the nature of the principal organic intermediates and the evolution of the mineralization as well as on the degradation pathways followed during the process. Major identified intermediates are hydroxylated derivatives, aromatic amines, naphthoquinone, phenolic compounds and several organic acids. By-products evaluation and toxicity measurements are the key-actions in order to assess the overall process.

'Racial' differences in genetic effects for complex diseases.

Abstract: 'Racial' differences are frequently debated in clinical, epidemiological and molecular research and beyond. In particular, there is considerable controversy regarding the existence and importance of 'racial' differences in genetic effects for complex diseases influenced by a large number of genes. An important question is whether ancestry influences the impact of each gene variant on the disease risk. Here, we addressed this question by examining the genetic effects for 43 validated gene-disease associations across 697 study populations of various descents. The frequencies of the genetic marker of interest in the control populations often (58%) showed large heterogeneity (statistical variability) between 'races'. Conversely, we saw large heterogeneity in the genetic effects (odds ratios) between 'races' in only 14% of cases. Genetic markers for proposed gene-disease associations vary in frequency across populations, but their biological impact on the risk for common diseases may usually be consistent across traditional 'racial' boundaries.

Modeling complex systems using fuzzy cognitive maps

Abstract: This research deals with the soft computing methodology of fuzzy cognitive map (FCM). Here a mathematical description of FCM is presented and a new methodology based on fuzzy logic techniques for developing the FCM is examined. The capability and usefulness of FCM in modeling complex systems and the application of FCM to modeling and describing the behavior of a heat exchanger system is presented. The applicability of FCM to model the supervisor of complex systems is discussed and the FCM-supervisor for evaluating the performance of a system is constructed; simulation results are presented and discussed.

A classification scheme for mobilization regions of bacterial plasmids.

Abstract: Transmissible plasmids can be classified according to their mobilization ability, as being conjugative (self-transmissible) or mobilizable (transmissible only in the presence of additional conjugative functions). Naturally occurring mobilizable plasmids carry the genetic information necessary for relaxosome formation and processing, but lack the functions required for mating pair formation. Mobilizable plasmids have a tremendous impact in horizontal gene transfer in nature, including the spread of antibiotic resistance. However, analysis of their promiscuity and diversity has attracted less attention than that of conjugative plasmids. This review will focus on the analysis of the diversity of mobilizable plasmids. For this purpose, we primarily compared the amino acid sequences of their relaxases and, when pertinent, we compared these enzymes with conjugative plasmid relaxases. In this way, we established phylogenetic relationships among the members of each superfamily. We conducted a database and literature analysis that led us to propose a classification system for small mobilizable plasmids in families and superfamilies according to their mobilization regions. This review outlines the genetic organization of each family of mobilization regions, as well as the most relevant properties and relationships among their constituent encoded proteins. In this respect, the present review constitutes a first approach to the characterization of the global gene pool of mobilization regions of small mobilizable plasmids.

Differential genetic effects of ESR1 gene polymorphisms on osteoporosis outcomes.

Abstract: 2orless.Conversely,wefoundsignificantreductions in fracture risk. In women homozygous for the absence of an XbaI recognition site, the adjusted odds of all fractures were reduced by 19% (odds ratio, 0.81 [95% CI, 0.710.93]; P=.002) and vertebral fractures by 35% (odds ratio, 0.65 [95% CI, 0.49-0.87]; P=.003). Effects on fractures were independent of BMD and unaltered in adjusted analyses. No significant effects on fracture risk were seen for PvuII and TA repeats. Conclusions ESR1 is a susceptibility gene for fractures, and XbaI determines fracture risk by mechanisms independent of BMD. Our study demonstrates the value of adequately powered studies with standardized genotyping and clinical outcomes in defining effects of common genetic variants on complex diseases.

A similarity learning approach to content-based image retrieval: application to digital mammography

Abstract: In this paper, we describe an approach to content-based retrieval of medical images from a database, and provide a preliminary demonstration of our approach as applied to retrieval of digital mammograms. Content-based image retrieval (CBIR) refers to the retrieval of images from a database using information derived from the images themselves, rather than solely from accompanying text indices. In the medical-imaging context, the ultimate aim of CBIR is to provide radiologists with a diagnostic aid in the form of a display of relevant past cases, along with proven pathology and other suitable information. CBIR may also be useful as a training tool for medical students and residents. The goal of information retrieval is to recall from a database information that is relevant to the user's query. The most challenging aspect of CBIR is the definition of relevance (similarity), which is used to guide the retrieval machine. In this paper, we pursue a new approach, in which similarity is learned from training examples provided by human observers. Specifically, we explore the use of neural networks and support vector machines to predict the user's notion of similarity. Within this framework we propose using a hierarchal learning approach, which consists of a cascade of a binary classifier and a regression module to optimize retrieval effectiveness and efficiency. We also explore how to incorporate online human interaction to achieve relevance feedback in this learning framework. Our experiments are based on a database consisting of 76 mammograms, all of which contain clustered microcalcifications (MCs). Our goal is to retrieve mammogram images containing similar MC clusters to that in a query. The performance of the retrieval system is evaluated using precision-recall curves computed using a cross-validation procedure. Our experimental results demonstrate that: 1) the learning framework can accurately predict the perceptual similarity reported by human observers, thereby serving as a basis for CBIR; 2) the learning-based framework can significantly outperform a simple distance-based similarity metric; 3) the use of the hierarchical two-stage network can improve retrieval performance; and 4) relevance feedback can be effectively incorporated into this learning framework to achieve improvement in retrieval precision based on online interaction with users; and 5) the retrieved images by the network can have predicting value for the disease condition of the query.

UCHL1 is a Parkinson's disease susceptibility gene

Abstract: The reported inverse association between the S18Y variant of the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) gene and Parkinson's disease (PD) has strong biological plausibility. If confirmed, genetic association of this variant with PD may support molecular targeting of the UCHL1 gene and its product as a therapeutic strategy for PD. In this light, we performed a collaborative pooled analysis of individual-level data from all 11 published studies of the UCHL1 S18Y gene variant and PD. There were 1,970 cases and 2,224 unrelated controls. We found a statistically significant inverse association of S18Y with PD. Carriers of the variant allele (Y/Y plus Y/S vs S/S) had an odds ratio (OR) of 0.84 (95% confidence interval [CI], 0.73-0.95) and homozygotes for the variant allele (Y/Y vs S/S plus Y/S) had an OR of 0.71 (95% CI, 0.57-0.88). There was a linear trend in the log OR consistent with a gene dose effect (p = 0.01). The inverse association was most apparent for young cases compared with young controls. There was no evidence for publication bias and the associations remained significant after excluding the first published, hypothesis-generating study. These findings confirm that UCHL1 is a susceptibility gene for PD and a potential target for disease-modifying therapies.

A Comparison of cosmological models using recent supernova data

Abstract: We study the expansion history of the universe up to a redshift of $\mathrm{z}=1.75$ using the 194 recently published SnIa data by Tonry et al. and Barris et al. In particular we find the best fit forms of several cosmological models and $H(z)$ ansatze, determine the best fit values of their parameters and rank them according to increasing value of ${\ensuremath{\chi}}_{\mathrm{min}}^{2}$ [the minimum value of ${\ensuremath{\chi}}^{2}$ for each $H(z)$ ansatz]. We treat ${\ensuremath{\Omega}}_{0m}$ as a parameter using a reasonable prior and assume flat geometry of the universe. No prior assumptions are made about validity of energy conditions. The fitted models are fourteen and include standard cold dark matter (SCDM), cold dark matter with cosmological constant \ensuremath{\Lambda} (LCDM), dark energy with constant equation of state parameter w (quiessence), third order polynomial for $H(1+z),$ Chaplygin gas, Cardassian model, ${w(z)=w}_{0}{+w}_{1}z,$ ${w(z)=w}_{0}{+zw}_{1}/(1+z),$ an oscillating ansatz for $H(z),$ etc. All these models with the exception of SCDM are consistent with the present data. However, the quality of the fit differs significantly among them and so do the predicted forms of $w(z)$ and $H(z)$ at best fit. The worst fit among the data-consistent models considered corresponds to the simplest model LCDM $({\ensuremath{\chi}}_{\mathrm{min}}^{2}=198.7$ for ${\ensuremath{\Omega}}_{0m}=0.34)$ while the best fit is achieved by the three parameter oscillating ansatz $({\ensuremath{\chi}}_{\mathrm{min}}^{2}=193.8).$ Most of the best fit ansatze have an equation of state parameter $w(z)$ that varies between $w(z)\ensuremath{\simeq}\ensuremath{-}1$ for $zl0.5$ to $w(z)g0$ for $zg1.$ This implies that the sign of the pressure of the dark energy may be alternating as the redshift increases. The goodness of fit of the oscillating $H(z)$ ansatz lends further support to this possibility.

Testing the Value of Six Taxonomic Groups as Biodiversity Indicators at a Local Scale

Abstract: We examined six groups of taxa-woody plants, aquatic and terrestrial herpetofauna, small terrestrial birds, orchids, and Orthoptera-to determine their efficiency as biodiversity indicators in the Dadia Reserve in northern Greece. We investigated the indicator value of each group by examining the degree of congruence of its species-richness pattern with that of the other groups and the efficiency of its complementary network in conserving the other groups and biodiversity. The two techniques differed in many respects in their outputs, but they both showed woody plants as the best biodiversity indicator. There was in general low congruence in the species richness patterns across the different groups. Significant relationships were found between woody plants and birds, Orthoptera and terrestrial herpetofauna, and birds and aquatic herpetofauna. None of the optimal complementary networks of the groups we examined protected all species of the other groups. Nevertheless, the complementary network of woody plants adequately conserved all groups except orchids. We conclude that the principle of complementarity must be integrated into the methodology of evaluating an indicator. In an applied context, our results provide a scientific background on which to base a biomonitoring program for the Dadia Reserve. In a wider scope, if the group of woody plants prove an adequate biodiversity indicator for other Mediterranean areas as well, this will be important because it will facilitate conservation-related decisions for the entire Mediterranean region.

Fate of bound systems in phantom and quintessence cosmologies

Abstract: We study analytically and numerically the evolution of bound systems in universes with accelerating expansion where the acceleration either increases with time towards a Big Rip singularity (phantom cosmologies) or decreases with time (quintessence). We confirm the finding of Caldwell et al. [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).] that bound structures get dissociated in phantom cosmologies but we demonstrate that this happens earlier than anticipated in Ref. [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).]. In particular we find that the ``rip time'' when a bound system gets unbounded is not the time when the repulsive phantom energy gravitational potential due to the average $(\ensuremath{\rho}+3p)$ balances the attractive gravitational potential of the mass M of the system. Instead, the ``rip time'' is the time when the minimum of the time-dependent effective potential (including the centrifugal term) disappears. For the Milky Way galaxy this happens approximately 180 Myrs before the Big Rip singularity instead of approximately 60 Myrs indicated in [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).] for a phantom cosmology with $\mathrm{w}=\ensuremath{-}1.5$. A numerical reconstruction of the dissociating bound orbits is presented.

Impaired Endothelial Function in Young Women with Premature Ovarian Failure: Normalization with Hormone Therapy

Abstract: Normal menopause is associated with vascular endothelial dysfunction, an early stage of atherosclerosis. The effect of premature ovarian failure (or premature menopause) on endothelial function in young women is unknown. Endothelial function was assessed in 18 women with premature ovarian failure before and after 6 months of hormone therapy and was compared with the endothelial function of 20 age- and body mass index-matched premenopausal women. Brachial artery diameter was measured both during hyperemia (an index of endothelium-dependent vasodilation) and in response to glyceryl trinitrate (an index of endothelium-independent vasodilation). Flow-mediated dilation was significantly lower in women with premature ovarian failure at baseline (increase in brachial artery diameter during hyperemia by 3.06 4.33%) than in control women (increase by 8.84 2.15%; P < 0.0005). Glyceryl trinitrate-induced vasodilation did not differ between the groups. After hormone therapy for 6 months, flowmediated dilation was improved in women with premature ovarian failure, increasing by more than 2-fold (7.41 3.86%; P < 0.005 compared with pretreatment) and reaching normal values (P not significant compared with control women). Glyceryl trinitrate-induced vasodilation did not change after treatment in women with premature ovarian failure. Young women with premature ovarian failure have significant vascular endothelial dysfunction. Early onset of endothelial dysfunction associated with sex steroid deficiency may contribute to the increased risk of cardiovascular disease and mortality in young women with premature ovarian failure. Hormone therapy restores endothelial function within 6 months of treatment. (J Clin Endocrinol Metab 89: 3907–3913, 2004)

The Rab5 effector Rabankyrin-5 regulates and coordinates different endocytic mechanisms.

Abstract: The small GTPase Rab5 is a key regulator of clathrin-mediated endocytosis. On early endosomes, within a spatially restricted domain enriched in phosphatydilinositol-3-phosphate [PI(3)P], Rab5 coordinates a complex network of effectors that functionally cooperate in membrane tethering, fusion, and organelle motility. Here we discovered a novel PI(3)P-binding Rab5 effector, Rabankyrin-5, which localises to early endosomes and stimulates their fusion activity. In addition to early endosomes, however, Rabankyrin-5 localises to large vacuolar structures that correspond to macropinosomes in epithelial cells and fibroblasts. Overexpression of Rabankyrin-5 increases the number of macropinosomes and stimulates fluid-phase uptake, whereas its downregulation inhibits these processes. In polarised epithelial cells, this function is primarily restricted to the apical membrane. Rabankyrin-5 localises to large pinocytic structures underneath the apical surface of kidney proximal tubule cells, and its overexpression in polarised Madin-Darby canine kidney cells stimulates apical but not basolateral, non-clathrin-mediated pinocytosis. In demonstrating a regulatory role in endosome fusion and (macro)pinocytosis, our studies suggest that Rab5 regulates and coordinates different endocytic mechanisms through its effector Rabankyrin-5. Furthermore, its active role in apical pinocytosis in epithelial cells suggests an important function of Rabankyrin-5 in the physiology of polarised cells.

Preparation and structural study of binary phosphate glasses with high calcium and/or magnesium content

Abstract: Glasses of high CaO or MgO content in the systems x CaO (1 − x )P 2 O 5 (0.50 ⩽ x ⩽ 0.72) and x MgO (1 − x )P 2 O 5 (0.50 ⩽ x ⩽ 0.80) have been prepared for the first time using a twin roller device and studied by Raman spectroscopy. It has been shown that the structure of glasses depends on the type of alkali earth cation; the modification of the phosphate network is higher for the Ca containing glasses with respect to the Mg ones, at the same alkali earth content, due to the well defined Ca properties as a modifying cation. X-ray diffraction patterns of the thermally treated at 850 °C calcium containing glasses show precipitation of bioactive crystalline phases, such as β-Ca 3 (PO 4 ) 2 and β-Ca 2 P 2 O 7 . The molecular dynamics simulations have provided insight for the high Mg and Ca content phosphate glasses formation, where their average oxygen coordination number is calculated as five and six for all glass compositions studied, respectively.

A variational approach for Bayesian blind image deconvolution

Abstract: In this paper, the blind image deconvolution (BID) problem is addressed using the Bayesian framework. In order to solve for the proposed Bayesian model, we present a new methodology based on a variational approximation, which has been recently introduced for several machine learning problems, and can be viewed as a generalization of the expectation maximization (EM) algorithm. This methodology reaps all the benefits of a "full Bayesian model" while bypassing some of its difficulties. We present three algorithms that solve the proposed Bayesian problem in closed form and can be implemented in the discrete Fourier domain. This makes them very cost effective even for very large images. We demonstrate with numerical experiments that these algorithms yield promising improvements as compared to previous BID algorithms. Furthermore, the proposed methodology is quite general with potential application to other Bayesian models for this and other imaging problems.

Cell proliferation and cell cycle control: a mini review

Abstract: Tumourigenesis is the result of cell cycle disorganisation, leading to an uncontrolled cellular proliferation. Specific cellular processes-mechanisms that control cell cycle progression and checkpoint traversation through the intermitotic phases are deregulated. Normally, these events are highly conserved due to the existence of conservatory mechanisms and molecules such as cell cycle genes and their products: cyclins, cyclin dependent kinases (Cdks), Cdk inhibitors (CKI) and extra cellular factors (i.e. growth factors). Revolutionary techniques using laser cytometry and commercial software are available to quantify and evaluate cell cycle processes and cellular growth. S-phase fraction measurements, including ploidy values, using histograms and estimation of indices such as the mitotic index and tumour-doubling time indices, provide adequate information to the clinician to evaluate tumour aggressiveness, prognosis and the strategies for radiotherapy and chemotherapy in experimental researches.

Luteolin Inhibits Vascular Endothelial Growth Factor-Induced Angiogenesis; Inhibition of Endothelial Cell Survival and Proliferation by Targeting Phosphatidylinositol 3′-Kinase Activity

Abstract: In an attempt to identify phytochemicals contributing to the well-documented preventive effect of plant-based diets on cancer incidence and mortality, we have previously shown that certain flavonoids inhibit in vitro angiogenesis. Here, we show that the flavonoid luteolin inhibited tumor growth and angiogenesis in a murine xenograft model. Furthermore, luteolin inhibited vascular endothelial growth factor (VEGF)-induced in vivo angiogenesis in the rabbit corneal assay. In agreement, luteolin inhibited both VEGF-induced survival and proliferation of human umbilical vein endothelial cells (HUVECs) with an IC(50) of about 5 mumol/L. Luteolin inhibited VEGF-induced phosphatidylinositol 3'-kinase (PI3K) activity in HUVECs, and this inhibition was critical for both the antisurvival and antimitotic affects of the compound. Indeed, luteolin abolished VEGF-induced activation of Akt, a downstream target of PI3K conveying both survival and mitotic downstream signals. Because overexpression of a constitutively active form of Akt rescued HUVECs only from the antisurvival effects of luteolin, the result indicated that luteolin targeted mainly the survival signals of the PI3K/Akt pathway. With regard to its antimitotic activity, luteolin inhibited VEGF-induced phosphorylation of p70 S6 kinase (S6K), a downstream effector of PI3K responsible for G(1) progression. Indeed, VEGF-induced proliferation of HUVECs was sensitive to rapamycin, an inhibitor of p70 S6K activation. Surprisingly, luteolin did not affect VEGF-induced phosphorylation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases, a pathway that is considered important for the mitotic effects of VEGF. Thus, blockade of PI3K by luteolin was responsible for the inhibitory effects of the compound on VEGF-induced survival and proliferation of HUVECs. The antisurvival effects of luteolin were mediated via blockage of PI3K/Akt-dependent pathways, whereas inhibition of the PI3K/p70 S6K pathway mediated the antimitotic effects of the compound.

Metolachlor photocatalytic degradation using TiO2 photocatalysts

Abstract: The photocatalytic degradation of the herbicide metolachlor is studied, using TiO 2 photocatalysts. Apart from the titania aqueous dispersions, immobilized semiconductor thin films were used in order to evaluate their effectiveness. The films exhibit a rough, nanocrystalline configuration, ideal for heterogeneous processes. Additionally the thin films were silver modified to determine if noble metal nanoclusters affect the photocatalytic efficiency. The kinetics obtained demonstrated that powder titania ( t 1/2 =21 min) was more efficient for the photocatalytic decomposition of metolachlor compared to pure titania thin film catalysts ( t 1/2 =52 min), while the presence of silver ions in TiO 2 particles modification did not prove to promote the solar photocatalytic process. Intermediate products from the slurry system were isolated and identified by means of solid-phase extraction (SPE) coupled to gas chromatography–mass spectroscopy techniques (GC–MS). A proposed degradation pathway of metolachlor is presented, involving mainly hydroxylation and dealkylation reactions. In addition, toxicity studies based on the luminescence of the bacteria Vibrio fischeri before and after the photocatalytic treatment were performed. The results demonstrated that the transient intermediates formed were more toxic compared to parent compound. At low photocatalyst loads, the toxicity of the irradiated solution remains relatively high even though 88% of metolachlor is decomposed.

Extended-interval aminoglycoside administration for children: a meta-analysis

Abstract: Background. There has been a long-standing debate regarding whether aminoglycosides should be administered on a multiple daily dosing (MDD) or once-daily dosing (ODD) schedule. Several unique characteristics of the aminoglycosides make ODD an attractive and possibly superior alternative to MDD. These include concentration-dependent bactericidal activity; postantibiotic effect, which allows continued efficacy even when serum concentrations fall below expected minimum inhibitory concentrations; decreased risk of adaptive resistance; and diminished accumulation in renal tubules and inner ear. Objective. To assess the relative efficacy and toxicity of ODD, compared with MDD, of aminoglycosides among pediatric patients. Study Selection. Randomized, controlled trials among children, evaluating the relative efficacy and toxicity of ODD versus MDD of aminoglycosides, with similar total daily doses in the compared arms, were selected. Data Sources. PubMed (1966–2003) and Embase (1982–2003) databases, the Cochrane Controlled Trials Registry (2003), and references of eligible studies and pediatric review articles were searched. Data Extraction. Study population characteristics and outcome data were extracted independently in duplicate, and consensus was reached on all items. The following outcome data were considered: (1) clinical or microbiologic failure, as defined in each study; (2) clinical failure; (3) microbiologic failure; (4) primary nephrotoxicity, ie, any rise in serum creatinine or decrease in creatinine clearance with thresholds as defined in each study; (5) secondary nephrotoxicity, ie, urinary excretion of proteins or phospholipids; and (6) ototoxicity based on pure tone audiometry, brainstem auditory evoked responses, or otoacoustic emissions for neonates and infants, vestibular testing, clinical impression, or any other method. All of the efficacy and toxicity outcomes were evaluated at the end of therapy. Results. Identification of eligible studies and study characteristics: 24 eligible studies published between 1991 and 2003 were identified. Aminoglycosides were used in different clinical settings (neonatal intensive care unit: 6 studies; cystic fibrosis: 3 studies; cancer: 5 studies; urinary tract infections: 4 studies; diverse infectious indications: 5 studies; pediatric intensive care unit: 1 study). Aminoglycosides used included amikacin (9 studies), gentamicin (11 studies), tobramycin (2 studies), netilmicin (2 studies), and tobramycin or netilmicin (1 study). Efficacy: There was no significant difference between ODD and MDD in the clinical failure rate, microbiologic failure rate, and combined clinical or microbiologic failure rates, but trends favored ODD consistently. There was no between-study heterogeneity for any outcome. Efficacy analysis of all trials indicating either clinical or microbiologic failures demonstrated pooled failure rates of 4.6% (23 of 501 cases) in the ODD arms and 6.9% (34 of 494 cases) in the MDD arms. The fixed-effects risk ratio was 0.71 (95% confidence interval [CI]: 0.45–1.11). A statistically significant benefit was seen with ODD over MDD in trials using amikacin, whereas no statistical significance was seen in trials using other antibiotics. The pooled clinical failure rates were 6.7% (22 of 330 cases) in the ODD arms and 10.4% (34 of 327 cases) in the MDD arms. The fixed-effects risk ratio was 0.67 (95% CI: 0.42–1.07). The pooled microbiologic failure rates were 1.8% (5 of 283 cases) with ODD and 4.0% (11 of 275 cases) with MDD. The fixed-effects risk ratio was 0.51 (95% CI: 0.22–1.18). Nephrotoxicity: There was no significant difference between ODD and MDD in the primary nephrotoxicity outcomes. Secondary nephrotoxicity outcomes were significantly better with ODD. The pooled primary nephrotoxicity rates were 1.6% (15 of 955 cases) in the ODD arms and 1.6% (15 of 923 cases) in the MDD arms. The fixed-effects risk ratio was 0.97 (95% CI: 0.55–1.69). The pooled secondary nephrotoxicity rates were 4.4% (3 of 69 cases) in the ODD arms and 15.9% (11 of 69 cases) in the MDD arms, suggesting a statistically significant superiority of ODD. The fixed-effects risk ratio was 0.33 (95% CI: 0.12–0.89). Results were consistent across types of clinical settings and aminoglycosides. Ototoxicity: There was no significant difference between ODD and MDD in the primary ototoxicity outcomes. The pooled ototoxicity rates for studies that provided auditory testing results were 2.3% (10 of 436 cases) in the ODD arms and 2.0% (8 of 406 cases) in the MDD arms. The fixed-effects risk ratio was 1.06 (95% CI: 0.51–2.19). In studies that provided clinical vestibular function testing results, no toxicity was documented among 209 patients given ODD and 206 patients given MDD. Studies noting only the clinical impression of hearing impairment also failed to identify any toxicity (ODD: 114 cases; MDD: 114 cases). Subgroup and bias analyses: We detected no statistically significant differences between ODD and MDD in any of the examined subgroups (neonatal intensive care unit, cystic fibrosis, cancer, or urinary tract infection), with respect to combined clinical or microbiologic failure outcomes, primary nephrotoxicity outcomes, or ototoxicity (based on auditory testing), when sufficient data were available. Moreover, there was no significant relationship between the effect size (risk ratio) and the trial size for any of the outcomes. Data Interpretation. Clinical failures were uncommon in the pediatric trials, regardless of the regimen used. If anything, fewer clinical failures tended to occur with ODD. Moreover, we observed a trend toward decreased bacteriologic failures. One meta-analysis of adult data suggested that ODD might reduce nephrotoxicity, whereas other meta-analyses showed nonsignificant trends or no difference in nephrotoxicity outcomes. In our meta-analysis, we were not able to show any reduction in the risk of primary nephrotoxicity outcomes with ODD. However, the event rate was much lower among children, compared with adults, and the secondary nephrotoxicity outcomes favored ODD. Finally, although the 2 regimens seemed equivalent with respect to ototoxicity, reporting on ototoxicity outcomes was incomplete. Reassuringly, even in the trials that performed auditory testing, the rates of ototoxicity in the MDD arms were very low. These results were consistent with meta-analyses of adult data, which showed no difference in ototoxicity rates between ODD and MDD. Conclusions. Although single trials have been small, the available randomized evidence supports the general adoption of ODD of aminoglycosides in pediatric clinical practice. This approach minimizes cost, simplifies administration, and provides similar or even potentially improved efficacy and safety, compared with MDD of these drugs.

Preparation, characterization and investigation of catalytic activity for NO+CO reaction of LaMnO3 and LaFeO3 perovskites prepared via microemulsion method

Abstract: Two typical perovskites LaMnO3 and LaFeO3 have been successfully prepared via microemulsion method both in the reverse and bicontinuous state. Pure perovskite crystal phases are achieved at final calcinations temperature of 800 °C. The specific surface areas (Sp) of the obtained materials were 24 and 12 m2 g−1 for the LaMnO3 prepared via reverse and bicontinuous phase and while the corresponding Sp for LaFeO3 were 30 and 14 m2 g−1. SEM images have shown that perovskites developed via reverse micelles have smaller particle size than those developed via the bicontinuous phase. The perovskites were tested for NO+CO reaction and exhibited higher catalytic activity than similar materials prepared via the ceramic method. The reactants NO and CO react in a 2:1 ratio at low temperature but they convert in a 1:1 ratio at high temperatures. From the kinetic analysis the heat of NO adsorption is estimated. In the case of manganese-containing materials except for the Sp, the percentage of Mn3+OMn4+ pairs seems to be another critical factor which influences the catalytic activity.