Activity Of La0 Research Articles

Improvement in stability of La0.4Ba0.6CoO3 cathode by combination with La0.6Sr0.4Co0.2Fe0.8O3 for intermediate temperature-solid oxide fuel cells

Improvement in long-term stability and cathodic activity of La0.4Ba0.6CoO3 (BLC) was studied by mixing with La0.6Sr0.4Co0.2Fe0.8O3 (LSCF). LSCF exhibits good long-term stability; however, surface activity is not high like Co-based perovskite. On the other hand, the cathodic activity of BLC is high; however, long-term stability was not so good and large degradation at initial period is observed. Combination of the two oxides shows small overpotential as well as improved long-term stability. Effects of BLC/LSCF ratio on stability and overpotential were studied and it was found that BLC–LSCF (7:3) showed the most stable and small cathodic overpotential among the examined compositions. Although the power density was still slightly decreased over 24 h at 0.5 V terminal voltage, the maximum powder density of the cell using BLC–LSCF composite oxides for cathode shows 2.5 times larger than that of the cell using LSCF cathode and 1.06 times larger than that of BLC. Degradation rate is smaller than 4 % from 5 to 24 h on this BLC–LSCF cathode at current density as high as 682 mA/cm2 after 24 h operation.

Nanocrystalline Mixed Oxides Containing Magnesium Prepared by a Combined Sol-Gel and Self-Combustion Method for Catalyst Applications

MgFe2O4 spinel ferrite and La0.6Pb0.2Mg0.2MnO3 perovskite nanopowders were synthesized by a combined sol-gel and self-combustion method and heat treatment. The morphological and structural characterization of the obtained powders has been performed with various techniques: X-ray diffraction (XRD), SEM observations, EDAX spectroscopy and BET analysis. The samples have been catalytically tested in flameless combustion reaction of acetone, benzene, propane and Pb free gasoline at atmospheric pressure. The results revealed a higher catalytic activity of La0.6Pb0.2Mg0.2 MnO3 perovskite than that of MgFe2O4 ferrite. This higher catalytic activity can be ascribed to smaller crystallite size (27 nm), larger surface area (8.5 m2/g) and the presence of manganese cations with variable valence (Mn3+ - Mn4+). The current results suggest that La0.6Pb0.2Mg0.2MnO3 perovskite is preferable to the Mg ferrite and that it can be a promising catalyst for acetone and propane combustion at low temperatures.

Interpretation and Recommended Testing for Antiphospholipid Antibodies

The antiphospholipid syndrome (APS) is defined by the association of arterial and/or venous thrombosis and/or pregnancy complications with the presence of at least one of the main laboratory-detected antiphospholipid antibodies (aPL) (i.e., lupus anticoagulants [LA], IgG and/or IgM anticardiolipin antibodies [aCL], and IgG and/or IgM anti-β2-glycoprotein I antibodies [aβ2GPI]). During the last decade efforts have been made to improve the harmonization and reproducibility of laboratory detection of aPL and guidelines have been published. The prognostic significance of aPL is being clarified through the fine elucidation of their antigenic targets and pathogenic mechanisms. Several clinical studies have consistently reported that LA is a stronger risk factor for both arterial and venous thrombosis compared with aCL and aβ2GPI. In particular, LA activity dependent on the first domain of β2-glycoprotein I and triple aPL positivity are prognosticators of the thrombotic and obstetric risks. Hopefully, this increasing knowledge will help improve diagnostic and treatment strategies for APS.

Lewis acid/surfactant rare earth trisdodecylsulfate catalysts for biodiesel production from waste cooking oil

This work reports the synthesis, characterization and application of rare earth (La, Ce, Sm and Gd) trisdodecylsulfate materials as Lewis acid-surfactant-combined catalysts for the production of biodiesel from waste cooking soybean oil. All the solid materials showed a bilayer lamellar arrangement with the dodecylsulfate molecules in a head to head, tail to tail packing. The reaction between commercial feedstocks (soybean oil and oleic acid) with ethanol was used separately to study La, Ce, Sm and Gd catalyst activities for transesterification (conversions of 73, 92, 53 and 73%) and esterification (conversions of 87, 80, 75 and 85%) after 1h, respectively. Among them, cerium(III) trisdodecylsulfate showed the highest catalytic activity (TOF=29.5molh−1molcat−1) for transesterification, while lanthanum(III) and gadolinium(III) trisdodecylsulfates were the most active for esterification (TOF=28.7molh−1molcat−1). The application of the studied catalysts for the simultaneous transesterification and esterification reaction of waste cooking oil, containing 8.8wt.% of free fatty acids (FFAs), with ethanol showed conversions of 76 (3.3wt.% of FFAs), 79 (5.3wt.% of FFAs), 81 (2.5wt.% of FFAs) and 86% (0.0wt.% of FFAs) after 1h for La, Ce, Sm and Gd catalysts, respectively. Thus, gadolinium(III) trisdodecylsulfate was the best material for the conversion of waste feedstock to produce biodiesel. However, cerium(III) trisdodecylsulfate was less susceptible to deactivation, exhibiting conversion values of 92, 81 and 77% for the 1st, 2nd and 3rd reaction cycles. The catalysts were characterized by elemental analysis, X-ray powder diffraction (XRD), 1H NMR, thermal analysis (TG/DTG/DTA) and FTIR measurements.

The role of the lateral amygdala in the retrieval and maintenance of fear-memories formed by repeated probabilistic reinforcement.

The lateral nucleus of the amygdala (LA) is a key element in the neural circuit subserving Pavlovian fear-conditioning, an animal model of fear and anxiety. Most studies have focused on the role of the LA in fear acquisition and extinction, i.e., how neural plasticity results from changing contingencies between a neutral conditioned stimulus (CS) (e.g., a tone) and an aversive unconditioned stimulus (US) (e.g., a shock). However, outside of the lab, fear-memories are often the result of repeated and unpredictable experiences. Examples include domestic violence, child abuse or combat. To better understand the role of the LA in the expression of fear resulting from repeated and uncertain reinforcement, rats experienced a 30% partial reinforcement (PR) fear-conditioning schedule four days a week for four weeks. Rats reached asymptotic levels of conditioned-fear expression after the first week. We then manipulated LA activity with drug (or vehicle) (VEH) infusions once a week, for the next three weeks, before the training session. LA infusions of muscimol (MUSC), a GABA-A agonist that inhibits neural activity, reduced CS evoked fear-behavior to pre-conditioning levels. LA infusions of pentagastrin (PENT), a cholecystokinin-2 (CCK) agonist that increases neural excitability, resulted in CS-evoked fear-behavior that continued past the offset of the CS. This suggests that neural activity in the LA is required for the retrieval of fear memories that stem from repeated and uncertain reinforcement, and that CCK signaling in the LA plays a role in the recovery from fear after the removal of the fear-evoking stimulus.

Perovskite-Type Complex Oxides Catalyst Composed of Rare Earth-Alkaline Earth-Transition Metal Elements for Soot Combustion in the NO and O<sub>2</sub> Atmosphere

La0.85K0.15CoO3perovskite-tpye catalyst was prepared by a sol-gel method and characterized by catalytic activity analysis to study the effect of NO and O2on the combustion of soot. The catalytic activity of La0.85K0.15CoO3Catalyst was promoted with NO. No matter lean or rich oxygen conditions, the La0.85K0.15CoO3catalyst could ignite soot at low temperature. The results of XRD and FT-IR showed that La0.85K0.15CoO3catalyst has the desired perovskite-type structure, ABO3.

Pt-containing perovskite-type oxides used for catalytic methane combustion

A series of catalysts La0.95Ce0.05CoO3, La0.95Ce0.05Co0.95Pt0.05O3 and Pt/La0.95Ce0.05CoO3 were prepared by combustion method and impregnation method, respectively. The purpose of the present work was to study the effect of platinum, with the same loading, on the platinum-substituted perovskite and perovskite-supported platinum catalyst. The catalysts structure were characterized by X-ray diffraction (XRD), BET measurements, transmission electron micrographs (TEM) and the methane oxidation activity of the catalysts were investigated in detail. It was found that the catalytic activity of La0.95Ce0.05Co0.95Pt0.05O3 was superior to that of La0.95Ce0.05CoO3 and the activity performance of Pt/La0.95Ce0.05CoO3 was higher than that of La0.95Ce0.05Co0.95Pt0.05O3 for methane combustion.

The initial metabolic conversion of levulinic acid in Cupriavidus necator

Levulinic acid or 4-ketovaleric acid is a potential renewable substrate for production of polyhydroxyalkanoates. In this work, the initial reactions of LA metabolism by Cupriavidus necator were examined in vitro. The organic acid was converted by membrane-bound crude enzymes obtained from the cells pre-grown on LA, while no LA activity was detected from cells pre-grown on acetic acid. Acetyl-CoA and propionyl-CoA were two major intermediates in the initial reactions of LA conversion. A mass balance on propionyl-CoA accounts for 84 mol% of LA added in vitro. It explains an interesting phenomenon that 3-hydroxbutyrate and 3-hydroxyvalerate are two major monomers of the biopolyester formed from LA, instead of 4-hydroxvalerate that has the similar chemical structure of LA as the precursor. A Monod model was used to describe the kinetics of LA utilization as a sole carbon source or a co-substrate of glucose and fructose. The μ(max) and K(m) of LA alone were 0.26 h⁻¹ and 0.01 g/L, respectively. The content and composition of PHA are also dependent on the culture conditions such as carbon to nitrogen ratio. The in vitro observation is supported by the high utilization rate of LA and the high molar percentage of 3HB and 3HV in the PHA derived from LA.

Identification of the Crucial Substrates of Persistent Atrial Fibrillation by Isochronal Spectrum Analysis

Introduction: High frequency activation (HFA) were considered to be the critical substrate for AF maintaining. The purpose of this study was to detect the crucial substrates of persistent atrial fibrillation (PeAF) using a noncontact mapping system. Methods: 24 patients (male 24, age 53.1±11.2 years) with PeAF (duration 18±9 m) referred for ablation using a noncontact mapping (Ensite) were enrolled. LA activity during AF ongoing prior to ablation were recorded. ~8 sec activation data at 2048 locations were detected and processed into a Custom-written Matlab system for frequency analysis. Local atrial frequencies were estimated and superposed onto the individual 3D LA geometry. Regions with HFA were identified. Results: LA enlarge were documented in 14 patients (LA diameter: 40.7±4.4 mm). LA frequencies in PeAF varied from 4.0 to 11.8 Hz. Multiple regions with HFA were seen in 22 of 24 patients, a total of 77 regions were detected (mean 3.2/pts) as HFA areas. Of all 24 patients, HFA occurred most commonly in roof (21/24), interatrial septum (15/24), ridge (14/24) and anterior wall (10/24). HFA was much less common adjacent to the PVs (4/24). Conclusions: Crucial substrates of PeAF were identified in this study, mostly located in roof, ridge, septum, and anterior wall. Ablation lines across these regions may help to terminate the arrhythmia.

Phospholipid inhibitors

The antiphospholipid syndrome (APS) is defined by the association of arterial and/or venous thrombosis and/or pregnancy complications with the presence of at least one among the main antiphospholipid antibodies (aPL) (i. e., Lupus anticoagulants, LA, IgG and/or IgM anticardiolipin antibodies, aCL, IgG and/or IgM antiβ2-glycoprotein I antibodies, aβ2-GPI). Several clinical studies have consistently reported that LA is a stronger risk factor for both arterial and venous thrombosis compared to aCL and aβ2-GPI. In particular, LA activity dependent on the first domain of β2-GPI and triple aPL positivity are associated with the risk of thrombosis and obstetrical complications. Asymptomatic aPL-positive subjects do not require primary thromboprophylaxis. Venous thromboembolism is the most common initial clinical manifestation of APS. To prevent its recurrence indefinite anticoagulation is recommended. Long duration treatment with warfarin or aspirin is used after a first cerebral arterial thrombosis. Low molecular weight heparin (LMWH) with or without aspirin is recommended to reduce the rate of obstetrical complications of APS pregnant women.

Coronary Sinus Isolation: Evidence for Discrete CS-LA Connections

CS has muscular sheaths which connect it to atria.A 44 year old man with longstanding persistant AF had his previous ablation that included wide encircling PV antrum, roof line and endo-epicardial mitral isthmus (MI) ablation. Two years later he had recurrence of arrhythmia. PVs were reconsolidated, and roofline and MI block were confirmed. Atrial pacing induced a regular tachycardia (CL 340 ms) with proximal to distal CS activation. Activation and entrainment mapping in LA, RA and CS were suggestive of focal atrial tachycardia with earliest activation in anterior LA just superior to line of MI block. Activation in proximal CS was medial to lateral and in high lateral CS (lateral of the isthmus) was caudocranial but later than the proximal CS. Wide spaced double potentials were recorded at the site of earliest activation. Focal endocardial ablation just superior to MI line terminated arrhythmia. Endocardial ablation along CS was done but could not isolate CS. Epicardial ablation in CS starting distally did not affect the CS signals until an abrupt loss of CS atrial signals was observed while ablation in proximal CS and dissociated CS signals were noted after isolation.These features imply that CS had a discrete residual connection with atria near proximal CS. In such a case, activation pattern in CS does not imply LA activation.

Characterization and Photocatalytic Activity of La<sub>1.6</sub>Ln<sub>0.4</sub>Zr<sub>2</sub>O<sub>7</sub> (Ln= La, Nd, Dy, Er) Nanocrystals by Stearic Acid Method

La1.6Ln0.4Zr2O7 (Ln= La, Nd, Dy, Er) nanocrystals were prepared by stearic acid combustion method. The samples were characterized by powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) nitrogen adsorption, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity of La1.6Ln0.4Zr2O7 was evaluated by the photocatalytic degradation of methyl orange. The order of the photocatalytic activity was as following: La1.6Er0.4Zr2O7>La1.6Dy0.4Zr2O7> La1.6Nd0.4Zr2O7> La2Zr2O7. La1.6Dy0.4Zr2O7 showed that the best photocatalytic activity and the reason may be related to the big magnetic moment of Er3+. It may be considered largely to be caused by the partly occupied Ln4f levels. Since the solid samples have the same structure, the reason that La1.6Er0.4Zr2O7 shows the highest reactivity may be related to lowest Ln4f level of Er3+.

Antiulcer and gastric antisecretory effects of landolphia owariensis extracts in rats

Water, methanol and chloroform extracts of Landolphia owarensis were investigated for their effects on gastric acid secretion and ulceration in male albino rats. Two models of gastric lesion induced in experimental Wistar rats-HC1/ethanol-induced gastric lesions and Pylorus ligation-induced gastric lesions-were employed. In both models, the antiulcer activity of LA was compared with that of cimetidine (100 mg kg p.o.). In the HCl/Ethanol model, ulcer index and mucus production was determined. In pylorus ligated rat, ulcer index, mucus production, total volume of gastric juice and gastric acidity level were measured. Pre-treatment of animals with the aqueous extracts (100mg/kg and 200mg/kg) orally once daily for two weeks significantly reduced formation of ulcers induced by HCl/ethanol mixture, the percentage inhibition being 43.8 % and 55.27 % respectively. The chloroform extract afforded the least protection with 23.07 % and 14.77 % inhibition. This was also accompanied by significant increases in gastric mucus production. In pylorus ligated rats, total volume of gastric juice and gastric acidity was significantly decreased as compared to control group, to levels comparable to that produced by cimetidine. The results indicate that the leaf extracts of LO contains antiulcer principles.

The effect of short-term intoxication of rats with pentabromodiphenyl ether (in mixture mimic commercial products)

Until quite recently, pentabromodiphenyl ether (PentaBDE) was most commonly used as a flame retardant. Due to the considerably long atmospheric half-life of PentaBDE and its contribution to environmental pollution, it is categorized as a persistent organic pollutant (POP). As the data on the toxicity of PentaBDE is rather scarce, its potential acute toxicity was the subject of this study. PentaBDE was administered intragastrically to female rats, in a single dose (25, 200 or 2000 mg/kg b.w.). PentaBDE administered to rats disturbed redox homeostasis, which was manifested by lower total antioxidant status (TAS) in serum and by higher liver glutathione reduced (GSH) concentration. The toxic effect of PentaBDE intensified lipid peroxidation. On histopathological examination, administration of the highest PentaBDE dose (2000 mg/kg b.w.) was seen to induce symptoms of fatty liver. PentaBDE caused an increase in relative liver mass, cytochromes P-450 (after two highest doses), a dose-dependent increase in the activity of CYP lA (12-26 fold) and CYP 2B (5-6 fold) as well as the levels of CYP lAl (16-50 fold) and CYP 4A (2-3 fold) in liver.

Characteristics of P wave in patients with sinus rhythm after maze operation.

Maze operation could alter P wave morphology in electrocardiogram (ECG), which might prevent exact diagnosis of the cardiac rhythm of patients. However, characteristics of P wave in patients with sinus rhythm after the operation have not been elucidated systematically. Consecutive patients who underwent the modified Cox Maze operation from January to December 2007 were enrolled. The standard 12-lead ECG and echocardiography were evaluated in patients who had sinus rhythm at 6 months after the operation. The average axis of P wave was 65±30 degrees. The average amplitude of P wave was less than 0.1 mV in all 12-leads, with highest amplitude in V1. The most common morphology of P wave was monophasic with positive polarity (49%), except aVR lead, which was different from those in patients with enlarged left atrium, characterized by large P-terminal force in the lead V1. There were no significant differences in P-wave characteristics and echocardiographic parameters between patients with LA activity (30.6%) versus without LA activity (69.4%) at 6 months after the operation. In conclusion, the morphology of P wave in patients after Maze operation shows loss of typical ECG pattern of P mitrale: P wave morphology is small in amplitude, monophasic and with positive polarity.

Noninvasive real-time mapping of an incomplete pulmonary vein isolation using electrocardiographic imaging

Establishing entrance and exit block from pulmonary veins is an endpoint for pulmonary vein isolation (PVI) procedures (1). Reestablished pulmonary vein connection is a common cause of atrial fibrillation (AF) recurrence in patients who have previously undergone PVI. Here we provide images from a noninvasive cardiac electrophysiology imaging system (ECGI) performed during PVI. The ECGI procedure has been described previously (2) (3). 250 carbon electrodes were applied to the patient’s torso before a pre-procedural contrast-enhanced CT scan, which provided torso-electrode positions and atrial geometry in the same reference frame. The electrodes were removed, then replaced on the day of the PVI procedure in the same configuration, and remained on the patient throughout the procedure. ECGI performed during the procedure noninvasively generated epicardial isochrone activation maps. After circumferential ablation around the antrum of the right pulmonary veins, a lasso catheter in the right inferior pulmonary vein (RIPV) demonstrated entrance block. However, high-output pacing from within the RIPV captured the atrium, revealing incomplete exit block. Panel A displays the real-time ECGI isochrone map during RIPV pacing, showing earliest activation in the superior-posterior antrum of the RIPV (red is earliest), with radial spread across the posterior LA. A 60-ms delay is seen from the pacing breakthrough (red) to posterior LA (green) activation, consistent with incomplete line of block created by the ablation. The invasive electroanatomic map (Panel B) shows the final ablation lesion set and the additional ablation necessary for exit block from the RIPV (pink marker). This location on the invasive electroanatomic map corresponds closely to the exit site determined by ECGI in Panel A. Panel C shows an ECGI isochrone map during high-output pacing from within the RIPV after the complete ablation. Pacing failed to capture the atrium, and the earliest LA activation in sinus rhythm was near Bachmann’s bundle (red). Posterior LA activation is limited superiorly and inferiorly with lines of block (white dotted lines) corresponding to the ablation lines on the LA roof and posterior wall seen in panel B. Three PV’s also demonstrate electrical isolation (blue). Although the RSPV in Panel C appears to have electrical connection in sinus rhythm, the appearance of activation is due to far-field signal from the posterior right atrium in close proximity. Invasive testing of the RSPV demonstrated entrance and exit block. Rigorous prospective study is needed, but if real-time ECGI can accurately identify areas of incomplete PVI isolation, it may shorten procedure time and improve long-term success rates by pinpointing sites of incomplete linear ablation.

Evidence for a homogeneous primary magma at Piton de la Fournaise (La Réunion): A geochemical study of matrix glass, melt inclusions and Pélé's hairs of the 1998–2008 eruptive activity

Magmas erupted at Piton de la Fournaise volcano since 0.5 Ma, display a large petrological and chemical range (picrites, 2 types of transitional basalts and differentiated magmas) and low amplitude isotopic heterogeneities. The recent activity (1998–2008) includes all magma types except evolved magmas. Matrix glass compositions from quenched lavas and Pélé's hairs of the whole 1998–2008 period define a single differentiation trend from a common basaltic melt (MgO ~ 9%) for the first time identified in the 2007 magmas. More primitive melt compositions (MgO ~ 12.5%) are only evidenced by olivine crystals with high Fo contents (Fo 85–88.4). Evolutions of major and trace element of glass and mineral compositions are consistently modelled by a unique low pressure crystal fractionation process. The composition range of olivine melt inclusions is distinct from that of matrix glass and Pélé's hair and corresponds to equilibrium crystallisation in closed system of melts trapped from the main differentiation series at high temperature. The range of basaltic types at Piton de la Fournaise is the result of large variations in the differentiation degree (10 to 35% crystallisation) of a single primary basaltic melt and the addition in highly variable amounts (up to 50% in picrites) of co-genetic olivine or gabbroic cumulates. These cumulates may represent the shallow and dense bodies identified by seismic tomography and have likely been produced by the repetitive intrusion and differentiation of basalts along Piton de la Fournaise history. Depending on the shallow transfer paths, ascending magmas may disaggregate and incorporate various types of cumulates, explaining all particular features of basaltic magmas and picrites. These results emphasize the exceptional chemical homogeneity of the primary basaltic melt and of the differentiation process involved in volcanic activity of La Réunion hotspot since 0.5 Ma and the increasingly recognised role of melt–wall rock interactions in compositional and petrological diversity of erupted magmas.

Oxygen species and their reactivity in the mechanochemically prepared substituted perovskites La1 − x Sr x CoO3 − y (x = 0–1)

The oxygen species and their reactivity in the mechanochemically prepared substituted perovskites La1 − x Sr x CoO3 − y were studied using temperature-programmed reduction (TPR) of the samples with hydrogen. The experimental data were compared with data on the catalytic activity of the series of La1 − x Sr x CoO3 − y catalysts in the oxidation of CO, as well as with the real structures and surface compositions of the samples, which were studied in detail previously. As the strontium content was increased, the degree of reduction of the samples increased in the course of TPR and the TPR peaks shifted to the region of lower temperatures, except for the last sample containing no lanthanum (x = 1). An increase in the calcination temperature and time resulted in a decrease in TPR peak intensities and in a shift of the peaks to the region of higher temperatures. A reaction scheme was proposed for the reduction. In accordance with this reaction scheme, Co4+ in substituted cobaltites was reduced to Co0 at temperatures lower than 400°C. In the temperature region of 400–500°C, the Co3+ → Co2+ bulk reduction, as well as the deep reduction processes Co3+ → Co0 and Co4+ → Co0, occurred; substitution facilitated the above processes. At temperatures higher than 500°C, Co2+ → Co0 bulk reduction occurred. The observed reduction of the mechanochemically prepared samples depended on their microstructure, which was described previously. It was found that the activity of the samples in the oxidation of CO depends on the amount of the most weakly bound reactive surface oxygen species, which were removed in TPR with hydrogen to 150°C. No correlation between the amount of strongly bound (lattice) oxygen removed upon TPR and the activity of La1 − x Sr x CoO3 − y samples in the oxidation of CO was found.

Variations in ectoenzymatic hydrolytic activity in an oligotrophic environment (Southern Tyrrhenian Sea, W Mediterranean)

The variations in the expression of two hydrolytic ectoenzymes (leucine aminopeptidase – LA – and β glucosidase — BG) were studied in the southern Tyrrhenian Sea during spring 2004. This area is characterised by a complex morphology and hydrodynamism, which generate significant differences between different sectors, particularly in the 0–100 m layer. However, the area generally exhibits oligotrophic features such as low autotrophic pigment and organic matter concentrations and a higher bacterial biomass than the phytoplanktonic one. Despite this general bottom-up pressure, adaptations by the microbial consumers were indicated by the ectoenzymatic activities and by the relationships between the enzymes, their organic substrates and their producers (namely the bacteria). In particular, bacteria were able to exploit the inorganic N supply (nitrite + nitrate provided by irregular intrusions of intermediate waters) to escape the bottom-up limitation and produce enzymes such as BG devoted to the degradation of cellulose remnants and, therefore, also able to take advantage on this refractory organic matter. In the 200–800 m layer, where trophic limitation was strong due to the low values of potentially-labile organic matter (namely proteins), the peculiar hydrodynamism led to the formation of nepheloid layers rich in organic matter, which provided the bacteria with substrates and allowed the development of a significant correlation between LA activity and its own organic substrate. Furthermore, a reduction of the bottom-up pressure was also indicated by a higher mean bacteria cell size in the entire water column of the central and eastern sectors, and a significantly increased expression of BG related to the increase in the cell size. The ectoenzymatic activities, therefore, suggested that the southern Tyrrhenian Sea should be considered as a mosaic of subsystems, where the peculiar hydrological features stimulate bacterial adaptations and enhance the channelling of energy embedded in refractory materials into the food web.

Preparation and catalytic performance of La0.8Sr0.2CoO3 supported on the mullite fiber ceramic

The perovskite-type La0.8Sr0.2CoO3 supported on the mullite fiber porous ceramics was prepared by means of the impregnating method, and was then characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD); thus we can come to the conclusion that the perovskitetype composite oxidant can disperse on the surface of mullite fiber ceramics. The catalytic activity of the La0.8Sr0.2CoO3 for NO and CO was evaluated. The effect of the doped 0.1 wt-% PdCl2 on the catalytic activity of the perovskite-type La0.8Sr0.2CoO3 was also discussed. The results show that the conversion rates of NO and CO respectively reaches 74.5% and 99% at 601°C without doped Pd, and both reach 100% at 350°C with a little doped Pd.