Final Extent Research Articles

The increase of serum Bcl-2 concentration in moderate head injury outcome: The role of ACTH 4-10 Pro 8 -Gly 9 -Pro 10

Background:Traumatic brain injury (TBI) is one of the major causes of death and disability. Apoptosis after TBI contributes significantly to the final extent of tissue damage. The Bcl-2 family proteins are important apoptosis modulators which increased in injured neurons. Bcl-2 has shown an antiapoptotic effect in rats and mice. ACTH4-10Pro8-Gly9-Pro10 is a synthetic short fragment of ACTH devoid of hormonal effects and has neuromodulatory properties. ACTH4-10Pro8-Gly9-Pro10 has been shown to increase levels of Bcl-2 and BDNF in vitro as well as in vivo. It has been postulated that ACTH4-10Pro8-Gly9-Pro10 will result in improved clinical outcome and reduce hospital length of stay. The goal of this study is to compare the effect of standard therapy only with standard therapy and ACTH4-10Pro8-Gly9-Pro10, the increase of Bcl-2, and clinical outcome with reduction of hospital stay.Materials and Methods:Subjects of moderate head injury (MHI) with no indication of surgery were taken consecutively (n = 40) and separated into two groups: standard treatment only and standard treatment combined with ACTH4-10Pro8-Gly9-Pro10. Blood samples were taken on day 1 and day 5 from each subject for measurements of Bcl-2 concentration. Barthel Index and MMSE were measured, at discharge and hospital length of stay was noted.Results:Forty subjects have been involved in this study, three subjects died in the standard therapy group, and one subject in ACTH4-10Pro8-Gly9-Pro10 group. Bcl-2 serum level in standard therapy was 1.39 ± 0.75 ng/mL on day 1 and 1.48 ± 0.77 ng/mL on day 5. After treatment with ACTH4-10Pro8-Gly9-Pro10, Bcl-2 level was 1.39 ± 0.70 ng/mL on day 1 and 3.70 ± 1.02 ng/mL on day 5. The serum Bcl-2 concentration was significantly increased with ACTH4-10Pro8-Gly9-Pro10 therapy with shorter hospital length of stay (P < 0.05).Conclusion:ACTH4-10Pro8-Gly9-Pro10 increased serum Bcl-2 levels and reduced hospital length of stay significantly compared with standard therapy alone.

Microbial Reduction of Fe(III) under Alkaline Conditions Relevant to Geological Disposal

To determine whether biologically mediated Fe(III) reduction is possible under alkaline conditions in systems of relevance to geological disposal of radioactive wastes, a series of microcosm experiments was set up using hyperalkaline sediments (pH ~11.8) surrounding a legacy lime working site in Buxton, United Kingdom. The microcosms were incubated for 28 days and held at pH 10. There was clear evidence for anoxic microbial activity, with consumption of lactate (added as an electron donor) concomitant with the reduction of Fe(III) as ferrihydrite (added as the electron acceptor). The products of microbial Fe(III) reduction were black and magnetic, and a range of analyses, including X-ray diffraction, transmission electron microscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism confirmed the extensive formation of biomagnetite in this system. The addition of soluble exogenous and endogenous electron shuttles such as the humic analogue anthraquinone-2,6-disulfonate and riboflavin increased both the initial rate and the final extent of Fe(III) reduction in comparison to the nonamended experiments. In addition, a soluble humic acid (Aldrich) also increased both the rate and the extent of Fe(III) reduction. These results show that microbial Fe(III) reduction can occur in conditions relevant to a geological disposal facility containing cement-based wasteforms that has evolved into a high pH environment over prolonged periods of time (>100,000 years). The potential impact of such processes on the biogeochemistry of a geological disposal facility is discussed, including possible coupling to the redox conditions and solubility of key radionuclides.

NUMERICAL SIMULATIONS OF SPICULE ACCELERATION

Observations in the Hα line of hydrogen and the H and K lines of singly ionized calcium on the solar limb reveal the existence of structures with jet-like behavior, usually designated as spicules. The driving mechanism for such structures remains poorly understood. Sterling et al. shed some light on the problem mimicking reconnection events in the chromosphere with a one-dimensional code by injecting energy with different spatial and temporal distributions and tracing the thermodynamic evolution of the upper chromospheric plasma. They found three different classes of jets resulting from these injections. We follow their approach but improve the physical description by including non-LTE cooling in strong spectral lines and non-equilibrium hydrogen ionization. Increased cooling and conversion of injected energy into hydrogen ionization energy instead of thermal energy both lead to weaker jets and smaller final extent of the spicules compared with Sterling et al. In our simulations we find different behavior depending on the timescale for hydrogen ionization/recombination. Radiation-driven ionization fronts also form.

Screening for Cognitive Impairment in a Stroke Prevention Clinic Using the MoCA

Screening for cognitive impairment is recommended in patients with cerebrovascular disease. We sought to establish the incidence of cognitive impairment using the Montreal Cognitive Assessment (MoCA) in a cohort of consecutive patients attending our stroke prevention clinic (SPC), and to determine whether a subset of the MoCA could be derived for use in this busy clinical setting. The MoCA was administered to 102 patients. Incidence of cognitive impairment was compared to presenting complaint and final diagnosis. extent of cerebral white matter changes (WMC) was rated using the Age Related White Matter Changes (ARWMC) scale in 80 patients who underwent neuroimaging. A subset of the three most predictive test elements of the MoCA was derived using regression analysis. 63.7% of patients scored <26/30 on the MoCA, in keeping with cognitive impairment. This was unrelated to the final diagnosis or extent of WMC, although a trend for lower MoCA scores was observed in older patients. A mini-MoCA subscore combining the clock drawing test, five-word delayed recall, and abstraction was highly correlated with the final MoCA score (R=0.901). A score of <7/10 using this 10-point mini-MoCA identified cognitive impairment as defined by the MoCA with a sensitivity of 98.5%, and a specificity of 77.6%. Two-thirds of SPC patients demonstrated evidence for cognitive impairment, irrespective of their final diagnosis or the presence of WMC. A mini-MoCA comprised of the clock drawing test, five-word delayed recall, and abstraction represents a potential alternative to the full MoCA in this population.

B-cell subpopulations in humans and their differential susceptibility to depletion with anti-CD20 monoclonal antibodies

In humans, different B-cell subpopulations can be distinguished in peripheral blood and other tissues on the basis of differential expression of various surface markers. These different subsets correspond to different stages of maturation, activation and differentiation. B-cell depletion therapy based on rituximab, an anti-CD20 mAb, is widely used in the treatment of various malignant and autoimmune diseases. Rituximab induces a very significant depletion of B-cell subpopulations in the peripheral blood usually for a period of 6 to 9 months after one cycle of therapy. Cells detected circulating during depletion are mainly CD20 negative plasmablasts. Data on depletion of CD20-expressing B cells in solid tissues are limited but show that depletion is significant but not complete, with bone marrow and spleen being more easily depleted than lymph nodes. Factors influencing depletion are thought to include not only the total drug dose administered and distribution into various tissues, but also B-cell intrinsic and microenvironment factors influencing recruitment of effector mechanisms and antigen and effector modulation. Available studies show that the degree of depletion varies between individuals, even if treated with the same dose, but that it tends to be consistent in the same individual. This suggests that individual factors are important in determining the final extent of depletion.

Initial epidemic area is strongly associated with the yearly extent of soybean rust spread in North America.

Hosts of soybean rust (Phakopsora pachyrhizi) are sensitive to low temperatures, limiting this obligate parasite in the United States to overwintering sites in a restricted area along the Gulf Coast. This temperature sensitivity of soybean rust hosts allowed us to study spatial spread of epidemic invasions over similar territory for seven sequential years, 2005-2011. The epidemic front expanded slowly from early April through July, with the majority of expansion occurring from August through November. There was a 7.4-fold range of final epidemic extent (0.4 to 3.0 million km2) from the year of smallest final disease extent (2011) to that of the largest (2007). The final epidemic area of each year was regressed against epidemic areas recorded at one-week intervals to determine the association of final epidemic extent with current epidemic extent. Coefficients of determination for these regressions varied between 0.44 to 0.62 during April and May. The correlation coefficients varied between 0.70 and 0.96 from early June through October, and then increased monotonically to 1.0 by year's end. Thus, the spatial extent of disease when the epidemics began rapid expansion may have been a crucial contributor to subsequent spread of soybean rust. Our analyses used presence/absence data at the county level to evaluate the spread of the epidemic front only; the subsequent local intensification of disease could be strongly influenced by other factors, including weather.

Hydraulic model evaluation for large‐scale flood risk assessments

AbstractFor a nationwide flood risk assessment in Germany, simulations of inundation depth and extent for all major catchments are required. Therefore, a fast two‐dimensional (2D) hydraulic model is needed. From the range of existing methods, two storage cell models are evaluated to find an appropriate method for large‐scale applications. The Dynamic Rapid Flood Spreading Model (Dynamic RFSM) based on irregular storage cells, and a raster‐based model with inertia formulation of momentum equation are compared. Simulation performed with the fully dynamic shallow water model InfoWorks RS 2D served as a reference. The hydraulic models are applied to a test area having a very flat topography adjacent to the river Elbe. As a benchmark scenario, the outflow through a hypothetical dike breach was chosen. To investigate the impact of the grid resolution on run time and model performance, the simulation with the raster model is carried out with different grid sizes. Furthermore, the sensitivity of the Dynamic RFSM to the choice of time step was analysed. Both models were able to simulate the final inundation extent and depths with a reasonable accuracy. However, the Dynamic RFSM showed some weakness in simulating inundation extent over the flat test area. Coarsening the grid resolution reduced the run time of the raster‐based model considerably and can be regarded as a promising strategy to constrain the computational efforts for a large‐scale application, although the model accuracy gradually deteriorated. With similar run time, the raster‐based model performed better than the Dynamic RFSM in terms of inundation extent and comparable regarding maximum inundation depth. Generally, an application at national scale appears feasible with both hydraulic modelling schemes. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Time Dependence of Reliability of Noncontrast Computed Tomography in Comparison to Computed Tomography Angiography Source Image in Acute Ischemic Stroke

There is no consensus on how the reliability and predictive ability of noncontrast computed tomography (NCCT) and computed tomography angiography source image (CTASI) change over time from acute ischemic stroke onset. We hypothesized that the reliability for detecting early ischemic changes (EIC) would be lower in early time periods and that changes identified on CTASI would be more reliable across examiners than changes identified on NCCT. To address this, we compared the relationships between CTASI, NCCT, and final infarct in patients with initial computed tomography (CT) imaging at different time points after stroke onset. Patients with acute ischemic stroke with proximal anterior circulation occlusions (internal carotid artery, middle carotid artery M1, proximal M2) from Calgary CT Angiography (CTA) database were studied. The cohort was categorized in four groups based on time from stroke onset to baseline NCCT/CTA: 0-90 mins (n = 69), 91-180 mins (n = 88), 181-360 mins (n = 46), and >360 mins (n = 58). Median scores of NCCT-Alberta Stroke Program Early CT Score (ASPECTS), CTASI ASPECTS, and follow-up ASPECTS among different time categories were compared. To determine reliability, a subsample of NCCT brain and CTASI were interpreted at separate sessions weeks apart by two neuroradiologists and two stroke neurologists in random order. Median and mean ASPECTS ratings on NCCT and CTASI were higher than final ASPECTS in each time category (P < 0·001 for all comparisons). CTASI ASPECTS was lower than NCCT ASPECTS in each time category, and differences were significant at 0-90 mins and 91-180 mins (P < 0·001). The least agreement among readers was in detection of EIC on NCCT brain in the ultra-early phase (<90 mins) [intraclass correlation coefficient (ICC) = 0·48. By contrast, there was excellent agreement on EIC on CTASI regardless of time period (ICC = 0·87-0·96). Using ASPECTS methodology, CTASI is more reliable than NCCT at predicting final infarct extent particularly in the early time windows.

Feather selection and replacement patterns demonstrate that Goldfinches Carduelis carduelis fix postjuvenile moult extent prior to moult initiation

Birds undergoing a partial moult have to make important decisions regarding moult extent, pattern and sequence. Moreover, since partial moults are usually subject to a great degree of individual variability, the mechanisms controlling and organising such moults can be particularly complex. In the present paper, I investigate the feather selection and replacement process involved in partial postjuvenile moult in the Goldfinch Carduelis carduelis. Moult patterns observed after moult completion indicate that birds select the feathers to be replaced according to a predetermined order of moult priorities. However, the sequence of feather replacement, both within and between feather tracts, differs markedly from this order of moult priorities, varying individually to be adjusted to the final moult extent. These results indicate that, prior to or at the beginning of moult, each bird fixes with precision which feathers will be replaced. These findings have important implications for the interpretation of partial and incomplete moult patterns and for our understanding of the underlying factors controlling moults.

Lack of clinically significant pharmacological interactions between ticagrelor and enoxaparin or unfractionated heparin in healthy subjects

Patients with acute coronary syndromes (ACS) receive several pharmacological therapies concomitantly, including antiplatelet and anticoagulant agents. As unfractionated heparin (UFH) activates platelets in vitro and in vivo, co-administration with an antiplatelet agent may lead to decreased clinical effectiveness of the latter. The aim was therefore to determine any potential drug-drug interactions between the new oral antiplatelet agent ticagrelor, and UFH or enoxaparin. In two open-label, three-period, crossover trials, healthy subjects were randomized to receive ticagrelor alone or with enoxaparin (study 1) or UFH (study 2), or enoxaparin or UFH alone. Ticagrelor plasma concentrations, inhibition of platelet aggregation (IPA), anti-factor Xa levels, activated partial thromboplastin time (aPTT) and activated coagulation time (ACT) were measured. Thirty and 28 subjects completed studies 1 and 2, respectively. Study drugs were generally well tolerated, with no significant bleeding or serious adverse events. Co-administration with enoxaparin or UFH had no significant effect on ticagrelor pharmacokinetics. The effect of ticagrelor on IPA was unimpaired by co-administration of enoxaparin, except for a marginal (-2.9%; 908.7%.h, 881.9%.h) reduction in final extent area under the effect curve (AUEC)(2-12) (95% CI: -51.6%.h, -2.0%.h). Co-administering UFH with ticagrelor caused small decreases in IPA(max) (-3.8%; 94.6%, 91.0%) and AUEC(2-12) (-6.8%; 888.6%.h, 828.3%.h) vs. ticagrelor alone (95% CI: final extent IPA(max) -5.7%, -1.6%; AUEC(2-12) -109.8%.h, -10.8%.h). Ticagrelor had no clinically significant effects on enoxaparin as assessed by anti-factor Xa (study 1), or UFH as assessed by aPTT or ACT (study 2). Enoxaparin and UFH had no effect on the pharmacokinetics and no clinically significant effect on the pharmacodynamics of ticagrelor. Ticagrelor had no clinically significant effects on the pharmacodynamics of enoxaparin or UFH.

Quantitative kinetic and structural analysis of geopolymers. Part 1. The activation of metakaolin with sodium hydroxide

Isothermal conduction calorimetry (ICC) is used here to measure the kinetics of geopolymerisation of metakaolin by reaction with NaOH solution under a variety of conditions. Three exothermic peaks are observed in the calorimetric curve, and are assigned to the dissolution of metakaolin, the formation of geopolymer with disordered or locally ordered structure, and finally the reorganization and partial crystallization of this inorganic polymer gels. For the purpose of further quantifying the ICC data, the geopolymeric reaction products are assumed to have an analcime-like local structure, and their standard formation enthalpies are estimated from the available data for this structure. This assumption enables ICC to be used for the first time in a quantitative manner to determine the real reaction kinetics of geopolymerization. Increasing the NaOH concentration up to a molar overall Na/Al ratio of 1.1 is seen to enhance the reaction extent observed at 3 days, up to a maximum of around 40% in the high liquid/solid ratio systems studied here, and accelerates the crystallization process. However, further addition of NaOH does not give any additional reaction within this period, or any further acceleration. Raising the reaction temperature from 25°C to 40°C increases the initial reaction rate but has little effect on the final reaction extent, particularly when Na/Al>1.

Effect of fines on segregation of binary mixtures in gas–solid fluidized beds

A numerical study was conducted for investigating the size segregation of binary mixtures in the presence of fines in bubbling gas–solid fluidized beds. The gas flow was modeled using the continuum theory and the solid phase was modeled by the discrete element method. The experimental data on the extent of segregation from literature were used to validate the simulation results of this pseudo-2D model. The effect of adding fines at different concentrations and various sizes was investigated. The results were analyzed in terms of inter-particle and fluid-particle forces as well as the coordination number of particles to comprehend the effect of fines on changing these parameters. The results suggested that adding fines increases segregation of small and large particles by lowering inter-particle interactions which results in enhanced mobility of larger particles. Furthermore, reducing the size of fines from 900μm to 500μm enhances the final extent of segregation while further decrease in size of fines diminishes the segregation. Full separation of fines from large and small particles was not achievable during the segregation process and a portion of fines remained in lower layers rather than being collected at the bed surface.

THE EFFECT OF A COMPETITOR ON A MODEL ADAPTIVE RADIATION

The ecological forces shaping adaptive radiations are of great interest to evolutionary ecologists. Here, we experimentally test the hypothesis that the diversification of a lineage should be limited in the presence of competition from another taxon. We do this by studying a model microbial adaptive radiation (the generation of phenotypic diversity in asexual lineages of the bacterium Pseudomonas fluorescens) in the presence or absence of a competitor (Pseudomonas putida). In a spatially heterogeneous environment, the competitor P. putida reduced P. fluorescens population size only slightly and had no effect on diversification. In a spatially homogeneous environment, the competitor reduced P. fuoresecens population size to a much greater extent. Again the final extent of diversification in P. fluorescens was not affected by the competitor, but early diversification was accelerated. In this environment, P. putida suppressed the growth of a common variant of P. fluorescens and directly or indirectly facilitated the growth of a rare morph. Our results suggest that competition experienced by diversifying lineages may have complex effects on adaptive radiations not fully captured by current theory.

Quantification of the Kinetics and Extent of Self-Sorting in Three Dimensional Spheroids

The self-sorting of cells into distinct compartments in three-dimensional (3D) microtissues is a process critical to developmental biology, cancer metastasis, and tissue engineering. Although self-sorting has been studied since the 1950s, little quantitative data exist that describe this dynamic process. Here, we describe a recently developed assay designed to quantify the extent and kinetics of self-sorting in 3D. Mixtures of fluorescently labeled normal human fibroblasts (NHF) and hepatocyte (H35) cells were fluorescently labeled, red and green respectively, and seeded onto micro-molded non-adhesive hydrogels. The cells self-assembled into a spheroid and self-sorted with NHFs forming the central core and H35s forming the outer shell. A time course of fluorescent images was used to analyze the ratio of red (NHFs) and green (H35s) fluorescence in concentric hollow cylinders throughout a spheroid and was statistically compared with the fluorescent ratio of the perfectly sorted spheroid. We found that NHFs and H35s, at a 1:1 ratio, sorted to a final extent of 88±3% at an initial rate of 0.36±0.06% per minute and reached 50% self-sorted at 2.7±0.3 h. Studies with varying ratios of NHFs and H35s show that self-sorting and self-assembly are coincident in time when the proportion of NHFs are varied over a 6-fold range (14% to 85%). This method can, thus, be used to characterize the sorting behavior of additional pairs of cells, the effect of drugs, and growth factors that may change the kinetics of the process, and bring an understanding to the cellular mechanisms which control self-sorting.

Nanoemulsion- and emulsion-based delivery systems for curcumin: Encapsulation and release properties

Curcumin has been reported to have many biological activities, but its application as a functional ingredient is currently limited because of its poor water-solubility and bioaccessibility. This study investigated the impact of different lipid-based formulations on curcumin encapsulation and bioaccessibility. Oil-in-water nanoemulsions (r<100nm), or conventional emulsions (r>100nm), were prepared with different lipids: long, medium, and short chain triacylglycerols (LCT, MCT and SCT, respectively). An in vitro model simulating small intestine digestion conditions characterised rate and extent of lipid phase digestion. A centrifugation method determined fraction of curcumin released into mixed micelles after digestion (bioaccessibility). Initial digestion rate decreased in the order SCT>MCT>LCT, while final digestion extent decreased in the order MCT>SCT>LCT. The bioaccessibility of curcumin decreased in the order MCT>LCT≫SCT and appeared to be slightly higher in conventional emulsions than in nanoemulsions.

Earlier recovery of platelet function after discontinuation of treatment with ticagrelor compared with clopidogrel in patients with high antiplatelet responses

The rate of recovery of platelet function after discontinuation of P2Y(12) inhibitors depends on the reversibility of the antiplatelet effect and the extent of the on-treatment response. P2Y(12) inhibition increases the bleeding risk in patients requiring surgery. To evaluate recovery of platelet function after discontinuation of ticagrelor vs. clopidogrel in stable coronary artery disease (CAD) patients with high levels of platelet inhibition (HPI) during the ONSET/OFFSET study. Patients received aspirin 75-100 mg per day and either ticagrelor 90 mg twice-daily or clopidogrel 75 mg daily for 6 weeks. This subanalysis included patients with HPI after the last dose of maintenance therapy, defined as: inhibition of platelet aggregation (IPA) > 75% 4 h post-dose (ADP 20 μm, final extent); < 120 P2Y(12) reaction units 8 h post-dose (VerifyNow P2Y(12) assay); or platelet reactivity index < 50% 8 h post-dose (VASP-P assay). IPA > 75% was observed in 39 out of 47 ticagrelor-treated and 17 out of 44 clopidogrel-treated patients. The rate of offset of IPA over 4-72 h was greater with ticagrelor (IPA %/hour slope: -1.11 vs. -0.67 for clopidogrel; P < 0.0001). Mean IPA was significantly lower with ticagrelor than clopidogrel between 48 and 168 h post-dose (P < 0.01). Similar findings were observed with the other assays. The average time for IPA to decline from 30% to 10% was 50.8 h with ticagrelor vs. 110.4 h with clopidogrel. In patients with HPI, recovery of platelet function was more rapid after discontinuation of ticagrelor than clopidogrel leading to significantly greater platelet reactivity by 48 h after the last dose in the ticagrelor group.

Predicting Final Extent of Ischemic Infarction Using Artificial Neural Network Analysis of Multi-Parametric MRI in Patients with Stroke

In hemispheric ischemic stroke, the final size of the ischemic lesion is the most important correlate of clinical functional outcome. Using a set of acute-phase MR images (Diffusion-weighted - DWI, T1-weighted – T1WI, T2-weighted-T2WI, and proton density weighted - PDWI) for inputs, and the chronic T2WI at 3 months as an outcome measure, an Artificial Neural Network (ANN) was trained to predict the 3-month outcome in the form of a voxel-by-voxel forecast of the chronic T2WI. The ANN was trained and tested using 12 subjects (with 83 slices and 140218 voxels) using a leave-one-out cross-validation method with calculation of the Area Under the Receiver Operator Characteristic Curve (AUROC) for training, testing and optimization of the ANN. After training and optimization, the ANN produced maps of predicted outcome that were well correlated (r = 0.80, p<0.0001) with the T2WI at 3 months for all 12 patients. This result implies that the trained ANN can provide an estimate of 3-month ischemic lesion on T2WI in a stable and accurate manner (AUROC = 0.89).

A new model for large landslides in sensitive clay using a fracture mechanics approach

A new model is proposed for the development of large landslides in sensitive clay, and supported by concepts from fracture mechanics. A key assumption in this new model is that the complete failure surface develops before the onset of significant movement, thus predetermining the final extent of failure. The appearance of retrogression is actually the rear- ward advancing disruption of a monolithic slide mass over a growing zone of liquefied clay. It is seen that the likelihood of propagation of failure, and the resulting occurrence of a large landslide, depend primarily on the brittleness of the sensitive clay. The potential length of shear band propagation is limited by slope geometry, and increases for higher riverbanks and for flatter slopes above the riverbank. The model explains why large landslides in sensitive clay often terminate just adjacent to a reverse break in slope, such as an older landslide crater or a stream gully. The model also indicates that large landslides in sensitive clay could be expected to occur suddenly after a large single perturbation, such as an earthquake, or after a seemingly innocuous small trigger following the accumulation of a large number of annual load cycles, as observed fre- quently in nature.

Effect of Interaction between Transition Metal Oxides and Nitrogen Atoms on Thermal Stability of Polybenzoxazine

To investigate the interaction of transition metal oxides with polybenzoxazine and their influence on the thermal degradation mechanism of polybenzoxazine, transition metal oxides Y2O3, La2O3, Pr6O11, and Gd2O3 were added to benzoxazine monomer based on p-cresol and aniline to prepare polybenzoxazine composites. The chemical structures and final polymerization extent of polybenzoxazine and its composites were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and differential scanning colorimetry (DSC). The molecular weights of these cured samples were determined by gel permeation chromatography (GPC). The influence of transition metal oxides on the thermal properties of polybenzoxazine matrix was investigated using dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), thermogravimetric analyzer interfaced with Fourier transform infrared spectroscopy (TG-IR), and (pyrolysis-gas chromatography-mass spectrometry) Py-GC-MS. The results show that transition metal oxides can form coordination interactions with the nitrogen atoms of polybenzoxazine. The coordination interaction can anchor the aniline and make the molecular weights of polybenzoxazine matrix increase, which delays evaporation of aniline during thermal degradation, improves the char yield at 800°C, and increases the glass transition temperatures (Tg) of polybenzoxazine composites.

The Influence of Surfactants and Metals on the Mineralization of 14C-Labeled Methyl Parathion in a Mediterranean Soil under Aerobic Conditions

The mineralization of 14C-labeled methyl parathion, in a soil from a semiarid Mediterranean area, was followed by a simple method. This method consisted in trapping evolved CO2 in a NaOH trap, using common laboratory glassware and low quantities of reagents. Volatiles were trapped in polyurethane foams, which are cheap and easy to handle. The influence of soil water content (10–20%) and the addition of surfactants [Aerosol 22 and hexadecyl trimethyl ammonium bromide (HD)] and metals (Cu and Zn) were assessed. Different models were applied to evaluate parathion mineralization kinetics. Mineralization kinetics was initially faster for 20% soil water content, although the final mineralization extent was similar in the range of tested soil water content. Surfactants behaved differently: HD decreased mineralization rate while Aerosol 22 did not affect parathion mineralization. A bimetal Cu and Zn solution led to a significant decrease in methyl parathion mineralization, which persisted when applied together with HD. Results suggest a possible reduction of pesticide availability in soil or a direct effect of the exogenous chemicals on soil microbial community.