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Abstract: Glassy and rubbery epoxy–clay nanocomposites were synthesized by using various montmorillonite organoclays in order to investigate and compare the effect of the type of alkylammonium ion clay modifier on the structure and properties of the nanocomposites. The organoclays studied were the Nanomer I.28E and I.30E and the Cloisite C10A, C15A and C20A. The functionality (acidity), size and shape of backbone chain, hydrophobicity and polarity were the varying parameters of the organic modifiers that were correlated to the ability of the organoclays to form highly intercalated or exfoliated nanocomposites and to the changes observed in the mechanical (tensile measurements), thermo-mechanical (DMA) and thermal (TGA) properties of the epoxy nanocomposites. The primary alkylammonium ion modifiers with reactive/acidic hydrogen atoms, compared to the quaternary octadecyl, dihydrogenated tallow and benzyl-substituted hydrogenated tallow ammonium ions, were the most effective for the formation of exfoliated clay glassy and rubbery epoxy nanocomposites which exhibited improved properties compared to the pristine epoxy polymers. [Copyright &y& Elsevier]

Abstract: In the present study two synthetic mesoporous carbons, a highly ordered CMK-3 sample with hexagonal structure and a disordered mesoporous carbon (denoted DMC) were investigated for the sorption of Remazol Red 3BS (C.I. 239) dye in comparison to three commercial activated carbons and a HMS mesoporous silica with a wormhole pore structure. The structural, porosity and surface characteristics of the materials were evaluated using XRD, TEM, N2 porosimetry, FT-IR spectroscopy and zeta-potential measurements. Optimal dye sorption occurred at pH ∼2. Equilibrium sorption data followed the Langmuir model and showed that the two synthetic mesoporous carbons exhibit higher sorption capacities (q max ∼500–580mg/g at 25°C) in comparison to the commercial activated carbons which possessed either microporous (Takeda 5A and Calgon carbon) or combined micro-/mesoporous (Norit SAE-2) structures and to the HMS mesoporous silica. Thermodynamic parameters as the change in free energy, enthalpy, and entropy of sorption were also estimated. Kinetic studies were carried out and showed a rapid sorption of dye in the first ca. 30min while equilibrium was reached after ca. 3h. The sorption kinetics of dye was best described by a second-order kinetic model. A surfactant enhanced carbon regeneration (SECR) technique was used to regenerate the dye-loaded carbon sorbents. [Copyright &y& Elsevier]

Abstract: The in situ upgrading of biomass pyrolysis vapors with two mesoporous aluminosilicate materials (MSU-SBEA) assembled from zeolite Beta (BEA) seeds was tested in the present study, in comparison to conventional Al-MCM-41 and to non-catalytic biomass pyrolysis. The first sample (MSU-S/HBEA) exhibited an hexagonal mesopore structure while the second one (MSU-S/WBEA) possessed a wormhole-like mesopore structure with high textural porosity. The catalytic tests were performed on a fixed-bed reactor, the reaction temperature was 500°C and the feed was a lignocellulosic biomass based on beech wood. The use of the MSU-S catalytic materials led to significantly lower organic phase in the produced bio-oil and also to higher coke and char yields, compared to non-catalytic pyrolysis and to the use of Al-MCM-41 which induced a small increase in the yields of liquid oil and coke. Pyrolysis gases were also affected by all mesoporous catalysts. The MSU-S catalytic materials were very selective towards polycyclic aromatic hydrocarbons (PAHs) and heavy fractions, while they produced negligible amounts of acids, alcohols and carbonyls, and very few phenols. The MSU-S materials appeared to possess stronger acid sites than Al-MCM-41, resulting in enhanced yields of aromatics, PAHs and coke, as well as propylene in the pyrolysis gases. [Copyright &y& Elsevier]

Partially crystalline and X-ray amorphous ZSM-5 zeolite-based aluminosilicates have been synthesized and thoroughly characterized by chemical analysis, XRD, FT-IR, solid state MAS NMR, N2 adsorption, TEM, NH3-TPD and isopropanol dehydration as the catalytic test reaction. The X-ray amorphous and low-crystallinity samples were hydrothermally synthesized at temperatures as low as 25°C and consisted of nanosized well-formed particles of almost spherical shape and with dimensions of about 20–30nm. These samples exhibited very low microporosity and remarkably high meso/macropore volume (pore diameters ⩾30nm) and/or high external surface area. The first Bragg peaks were observed in the XRD patterns of the samples synthesized at 90°C and their position on the 2θ-axis was the same as those of a reference highly crystalline ZSM-5 zeolite sample. The particle/crystal size and microporosity of the partially crystalline materials increased with increasing hydrothermal synthesis temperature and % relative XRD crystallinity. Incorporation of aluminum in the ZSM-5 zeolitic framework was significantly enhanced at higher relative crystallinities, i.e. >60%. The X-ray amorphous aluminosilicates possessed tetrahedral aluminum atoms which were more zeolitic in character and induced a higher number of acidic framework hydroxyls (Brønsted acid sites), as compared to those found in a conventional silica–alumina. [Copyright &y& Elsevier]

The effects of rootstock variety (41B, 1103P and 110R), irrigation level (0.50, 0.75 and 1.00 of the evapotranspiration) and water quality (recycled versus freshwater) on water relations and gas exchange of potted Soultanina grapevines were investigated during two growing seasons. An early reduction of predawn leaf water potential (Ψpd) was detected for vines irrigated with recycled water in both the seasons. However, assimilation rate (A) and stomatal conductance (gs) were reduced only late in the first year at higher irrigation levels. This was consistent with the higher reduction of Ψpd at these treatments indicating that the development of a water deficit due to salt accumulation reduced gas exchange. At midday during 1998, leaves on vines grafted on 1103P and 110R had lower leaf water potentials and higher gs and A. An opposite effect was however observed early in June the following season, although later in that season no differences were detected among rootstocks. That differentiation of rootstock effect between seasons may have been induced by alterations in source/sink relations due to differences in yield among rootstocks and its effects on leaf area. Irrigation level strongly affected water relations and gas exchange. Both A and gs were significantly correlated with soil moisture. A differentiation in these relations was observed among rootstocks late in 1998 which probably resulted from the change in leaf area development among rootstocks during that period. [Copyright &y& Elsevier]

In the current study the effect of different clay type, as well as clay organomodifier, on solid state polymerization (SSP) of poly(ethylene terephthalate) (PET) was investigated. PET/clay nanocomposites containing Nanomer I.30E, Cloisite 10A and Laponite have been prepared by melt mixing and their structure was studied by X-ray diffraction measurements. Solid state was conducted at 220, 230 and 240 °C for 1, 2, 3 and 4 h under vacuum application. The I.30E organo-clay exhibited the higher immobilized amorphous fraction. This is due to its better dispersion and exfoliation of the clay nanolayers into the PET matrix, compared to the other organoclays. Intrinsic viscosity (IV) measurements after solid-state polymerization of nanocomposites revealed that IV increase is time and temperature dependent. However, nanocomposites exhibited much lower IV increase compared with neat PET. A simple kinetic model was employed to predict the time evolution of IV, as well as the carboxyl and hydroxyl content during SSP. From the experimental measurements and the theoretical simulation results it was proved that the higher aspect ratio of the nano-clay added, leads to higher inactivated hydroxyls end-groups concentration, higher activation energies and lower transesterification and esterification kinetic rate constants. Increased dispersion of the clay nanolayers in the polymer matrix in addition to increased aspect ratio, leads to better gas barrier properties, reducing the diffusivity and thus the removal of the polycondensation byproducts, i.e. water and EG. [ABSTRACT FROM AUTHOR]

Imbalanced Ca/Mg and excess Ni (due to serpentine stress) are limiting factors for plant productivity. The purpose of this study was to investigate if growth, nutrient uptake, PSII activity, photosynthesis and antioxidant activity of pomegranate (Punica granatum L., cv. Granada) plants were affected by serpentine stress. Pomegranate plants were grown in soil substrates from parent material marl (control), serpentine and serpentinized peridotite. Plant height, leaf, stem, root and total plant dry weight, as well as foliar N, P, K, Ca, Zn, Cu, chlorophyll content, fluorescence parameters, photosynthetic rate, and internal water use efficiency (WUEi) were significantly lower for the plants grown in the serpentinized peridotite soil. In contrast, higher ferric reducing antioxidant power (FRAP), total phenolics and total flavonoid content (TFC) levels were found in the serpentinized peridotite soil. The insignificant differences between the marl and serpentine soils in plant growth, PSII activity, photosynthesis and nutrient uptake indicated that P. granatum could tolerate a mild (not with extremely high Ni) serpentine stress. However, P. granatum could not tolerate stress showing excess Mg and imbalanced Ca/Mg, as found for the serpentinized soil of our study. • Soils from marl, serpentine and serpentinized peridotite were used as substrates. • Most foliar nutrients were significantly lower in the serpentinized peridotite soil. • Photosynthesis was significantly lower in the serpentinized peridotite soil. • Chlorophyll and PSII activity were significantly lower in the serpentinized soil. • Increased levels of phenols, TFC and FRAP were found in the serpentinized soil. [ABSTRACT FROM AUTHOR]

Highlights • Soils from marl, serpentine and serpentinized peridotite were used as substrates. • Most foliar nutrients were significantly lower in the serpentinized soil. • Photosynthesis was significantly lower in the serpentinized peridotite soil. • Increased levels of phenols, TFC and FRAP were found in the serpentinized soil. • Differential tolerance to serpentine stress between 'Wonderful' and 'Acco' existed. Abstract It was investigated if differential genotypic tolerance of two pomegranate cultivars ('Wonderful' and 'Acco') to serpentine stress existed. For this purpose, pomegranate plants were grown outdoors, in three soil substrates (from parent material marl, serpentine and serpentinized peridotite). The results indicated that growth, most foliar nutrient concentrations, total chlorophyll content, chlorophyll fluorescence and photosynthetic rate, for both genotypes, were significantly lower in the serpentinized peridotite soil (severe stress). In contrast, higher levels of total phenolics, total flavonoid content (TFC) and FRAP, were found in the serpentinized soil. Lower tolerance index to stress in the serpentinized soil was found for the cultivar 'Acco', than for 'Wonderful'. Overall, the physiological and antioxidant response of 'Acco' was worse, than that of 'Wonderful', under serpentine stress. In conclusion, despite the lower Ni, Cr and Mg accumulation of 'Acco' (compared to 'Wonderful'), its lower tolerance indices in the serpentinized soil probably shows its higher tissue sensibility to serpentine stress. Thus, this genotype should not be preferred for cultivation in soils presenting high degree of serpentinization (excess Mg concentrations). In contrast, from the tolerance indices of both genotypes in the serpentine soil, it is concluded that a mild stress existed in this case. [ABSTRACT FROM AUTHOR]

In the current study the effect of different mesoporous silica particles like MCF and SBA-15 on the solid state polymerization (SSP) of poly(ethylene terephthalate) (PET) was investigated. PET nanocomposites containing 1 and 2.5 wt% SBA-15 silica (average pore diameter 4.7 nm) and MCF silica (average pore diameter 14.2 nm) have been prepared by in-situ polymerization. All nanocomposites have been characterized using FTIR spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). SSP was conducted at 220, 230 and 240 °C for 1, 2, 3 and 4 h under vacuum. Intrinsic viscosity (IV) measurements after solid-state polymerization of nanocomposites revealed that PET/SBA-15 nanocomposites exhibited lower IV increase compared to neat PET, while the opposite was observed for PET/MCF nanocomposites, especially for 1 wt% MCF content. A simple kinetic model was employed to predict the time evolution of IV, as well as the carboxyl and hydroxyl content during SSP at different temperatures and reaction times. [ABSTRACT FROM AUTHOR]

Highlights: [•] C60/MCM-41 photocatalysts were prepared by the one-step wet impregnation (WI) method. [•] The catalysts were very effective in the photooxidation of organic compounds. [•] The intrinsic activity (TON or TOF) decreases as the C60 content increases. [•] WI instead of incipient WI leads to smaller C60 crystallites supported on MCM-41. [•] WI instead of incipient WI leads to higher activity of the high C60 content samples. [ABSTRACT FROM AUTHOR]

Abstract: In the present work we studied the N2O decomposition activity of nano-Ru/γ-Al2O3 catalysts prepared by in situ reduction with ethylene glycol (EG), in comparison to catalysts prepared via typical incipient wetness procedure. The metal content, particle size, dispersion and reduction characteristics of the supported Ru catalysts were studied by means of ICP-AES, XRD, HRTEM, TPR-H2 and TPD-H2. The EG reduction method favored the formation of almost spherical metallic Ru nanoparticles with the size of 1–3nm (HRTEM) and dispersion of 70–35% (TPD-H2), at Ru loading levels of 0.4–1wt.%. The impregnated-calcined catalysts exhibited larger Ru nanoparticles (10–80nm, TEM) with very low degree of dispersion (∼10%). The activity of the EG-prepared catalysts for the decomposition of N2O in oxygen rich feeds and in the absence or presence of NO, H2O, SO2, CO and CO2, was significantly higher compared to that of the impregnated-calcined samples and comparable with that of the most active catalytic systems reported in the literature for the treatment of combustion processes off-gases. The superior activity of the former catalysts, especially of the sample with low Ru content (0.4wt.% Ru, 1–2nm particle size), was attributed both to the high dispersion of Ru (70% dispersion), i.e., the high surface area of Ru metal available for reaction, and to the higher intrinsic activity and lower apparent activation energy of the very small supported Ru nanoparticles prepared by the EG reduction method. The EG-prepared nano-Ru/γ-Al2O3 catalysts could retain their high N2O decomposition activity (higher than 90%) for long time-on-stream by applying intermediate, short term regenerations in reducing atmosphere at moderate temperatures (i.e., 500°C); treatment of the partially deactivated catalysts under reducing (H2/He) atmosphere leads to elimination of Ru(SO4)2 that is usually formed during reaction via reduction of Ru4+ to active Ru metallic phase. [Copyright &y& Elsevier]

Abstract: Background: To investigate the combined prognostic value of admission serum levels of B-type natriuretic peptide (BNP), cardiac troponin I (cTnI) and high sensitivity C-reactive protein (hs-CRP), in patients hospitalized because of acutely decompensated severe (New York Heart Association class III/IV) low-output chronic heart failure (CHF). Methods: A total of 577 consecutive patients recruited in the 5 participating centers, were studied. Cardiac mortality by 31 days was the prespecified primary study end point. Results: A total of 102 (17.7%) patients died by 31 days. When the study patients were divided according to the number of elevated study biomarkers, there was a significant gradual increased risk of 31-day cardiac death with increasing in the number of elevated biomarkers (p <0.001). The value of the discriminant C statistic for the Cox regression analysis, increased significantly when each of the study biomarkers was incorporated with the other risk predictors into a Cox regression model, with the highest C statistic value for the Cox regression model that included all the study biomarkers (p <0.001). By multivariate Cox regression analysis, elevated serum levels of BNP (p =0.002), cTnI (p <0.001) and hs-CRP (p =0.02) were independent predictors of the study end point. Conclusions: In conclusion, in patients hospitalized for acute decompensation of severe (NYHA III/IV) low-output CHF, BNP, cTnI and hs-CRP upon admission offers enhanced early risk stratification. With increasing number of elevated biomarkers, the risk of 31-day cardiac death increases gradually that implies treatment intensification, and closer follow-up. [Copyright &y& Elsevier]

Abstract: The effect of the pretreatment (inert, oxidative, and reducing) of Ru/γ-Al2O3 catalyst on its activity and stability in the decomposition of N2O in the absence or presence of O2, SO2, H2O and NO X was studied in the present work. Decomposition of pure N2O was slightly enhanced by the H2-pretreated catalyst (metallic Ru) compared to the O2- or He-pretreated ones, owing to a cyclic oxidation–reduction pathway of metallic Ru. The observed decrease of activity by O2 or H2O addition was reversible compared to SO2 which caused a strong, irreversible deactivation of the catalyst, irrespective of the type of pretreatment. This was attributed to the formation of stable sulphates, mainly those on RuO2 surface, which could only be removed by regeneration under reducing (H2 in He) atmosphere at temperatures of ca. 500°C. Oxidative or inert regeneration required very high temperatures (i.e. >700°C) in order to decompose these sulphates. A method of retaining N2O conversion activity very high (≥98%) for long reaction times is suggested and is based on frequent and short-time (ca. 10min) regenerations of the catalyst under reducing atmosphere (ca. 5% H2 in He). The effect of co-feeding various reducing agents, such as CO or C3H6, on the N2O conversion activity in the presence of O2, SO2, H2O and NO X is negligible, mainly because they are oxidized at relatively low temperatures in the O2-rich feeds used in this study. [Copyright &y& Elsevier]

The aim of the present study was to evaluate whether an elevated plasma C-reactive protein (CRP) level provides any additional prognostic information to the validated Thrombolysis In Myocardial Infarction (TIMI) risk score in patients with acute coronary syndromes. For this purpose, 1,846 consecutive patients with either acute ST-segment elevation myocardial infarction (STEMI; 861 patients) or non-ST-segment elevation acute coronary syndrome (NSTEACS; 985 patients) were included. The incidence of 30-day death and 14-day composite of death, myocardial infarction (or repeat myocardial infarction) and recurrent ischemia was the prespecified primary end point in the STEMI and NSTEACS cohorts, respectively. The incidence of the primary end point was 9.8% and 23.6% in the STEMI and NSTEACS cohorts, respectively. A significantly increased risk of the primary end point was present with an increase in the STEMI and NSTEACS TIMI risk score (ptrend &#60; 0.001 for the 2 groups). A plasma CRP value of ≥5 and ≥3 mg/L (defined by receiver-operating characteristic analysis) was associated with a significantly increased risk of the primary end point in the STEMI and NSTEACS cohorts, respectively (p &#60; 0.001 for the 2 cohorts), and it was true throughout the subgroups of STEMI and NSTEACS TIMI risk scores. In conclusion, an elevated plasma CRP level appears to be a marker that adds prognostic information to the validated STEMI and NSTEACS TIMI risk score. The plasma CRP and TIMI risk score may be used together for enhanced risk stratification in the setting of acute coronary syndromes. [Copyright &y& Elsevier]

Clinoptilolite is one of the most commonly used natural zeolites in environmental and industrial applications. In this study, the activity and selectivity of two different clinoptilolite tuffs from Thrace region of Greece were investigated using the model reaction of propane dehydrogenation and were compared to those of synthetic proton and metal-modified ZSM-5 zeolite catalysts. The clinoptilolite bearing tuff from Metaxades (MCH) showed appreciable activity for propane dehydrogenation, similar to that of a steamed Cr-modified ZSM-5 zeolite and considerably higher compared to the second natural clinoptilolite tuff (SF) from the area of Pentalofos and to the H-ZSM-5 zeolite. The total propylene yield for the MCH sample at 540 °C was 8.4%, compared to 3.4% for SF, 5.3% for steamed H-ZSM-5 and 8.3% for steamed Cr-modified ZSM-5. The proton-exchanged forms of both natural zeolites showed improved conversion of propane but resulted in lower propylene selectivity due to subsequent hydrogen transfer, cracking and cyclo-oligomerization reactions induced by the higher number of framework Bro¨nsted acid sites. [Copyright &y& Elsevier]