Degradation of bromoxynil and trifluralin in natural water by direct photolysis and UV plus H2O2 advanced oxidation process

The degradation of two pesticides, bromoxynil and trifluralin, was investigated in ultrapure and natural water solutions under ultraviolet (UV) light and a combination of UV and hydrogen peroxide (H₂O₂). The effect of pH on the photooxidation of the pesticides was also studied. The results indicated that under direct photolysis with monochromatic light at 253.7 nm and different conditions, the photochemical rates followed first-order kinetics, with fluence-based rate constants ranging from 9.15 × 10⁻⁴ to 6.37 × 10⁻³ cm² mJ⁻¹ and 7.63 × 10⁻³ to 1.47 × 10⁻² cm² mJ⁻¹ for bromoxynil and trifluralin, respectively. Quantum yields, in the range of 0.08-0.25 for bromoxynil and 0.12-0.72 for trifluralin, were observed in experiments using ultrapure water. The study also found that the UV/H₂O₂ process enhanced the oxidation rate in comparison to direct photolysis. A 90% degradation with UV dose of 333 and 188 mJ cm⁻² was achieved for bromoxynil and trifluralin, respectively, in natural water, in presence of 8.8 × 10⁻⁴ M H₂O₂. To assess the aquatic toxicity, the Microtox^® 81.9% screening test protocol was used before and after treatment. The test results indicated a decrease in the acute toxicity of the samples after treatment for both pesticides.     

Structural performance of alkali/acid-ultrasound modified Agave fibers during the melt mixing process with polyvinyl alcohol

This study aims to investigate changes in the structural properties of alkali/acid-ultrasound modified Agave fibers and their performance immersed on a polyvinyl alcohol (PVA) matrix with plasticizer during melt mixing processing. Structural analysis revealed that ultrasound enhances the effectiveness of the conventional alkaline/acid treatments to modify fibers since the simultaneous treatment increased the partial removal of lignocellulosic components, water molecules, and amorphous regions which improved their processability on a PVA matrix. Specific energy consumption values indicated that during melt mixing the modified fibers required more energy to expose the chains of cellulose fraction to function as an interaction site for PVA chains. Once the mixture was homogenized, the fiber-matrix interactions promoted high viscosity, friction, and mechanical stress in the chamber. Therefore, the modified fibers restricted the interaction between plasticizer and PVA in the obtained films, resulting in a highly structured, and reinforced network, increasing the storage modulus as dynamic mechanical analysis indicated. These findings highlight a feasible way to valorize Agave fibers and allow the understanding of the matrix-fiber interactions during melt mixing processing, useful to predict the structural and mechanical properties of the films.     

Molecular interfacial reactions between Pu(VI) and manganese oxide minerals manganite and hausmannite

The sorption of Pu(VI) onto manganite (MnOOH) and hausmannite (Mn3O4) was studied as a function of time, solution pH, and initial plutonium concentration. Kinetic experiments indicate that the surface complexation of plutonium occurs over the first 24 h of contact with the mineral surface. The sorption increases with pH beginning at pH 3 until it reaches a maximum value of 100% at pH 8 (0.0011-0.84 micromol of Pu/m2 of manganite and 0.98-1.2 micromol of Pu/m2 of hausmannite) and then decreases over the pH range from 8 to 10. The ratio of solid to solution was 10 mg/mL for manganite experiments and 4 mg/mL for hausmannite samples. Carbonate was not excluded from the experiments. The amount of plutonium removed from the solution by the minerals is determined by a combination of factors including the plutonium solution species, the surface charge of the mineral, and the mineral surface area. X-ray absorption fine structure taken at the Pu L(III) edge were compared to plutonium standard spectra and showed that Pu(VI) was reduced to Pu(IV) after contact with the minerals. Plutonium sorption to the mineral surface is consistent with an inner-sphere configuration, and no evidence of PuO2 precipitation is observed. The reduction and complexation of Pu(VI) by manganese minerals has direct implications on possible migration of Pu(VI) species in the environment.     

Influence of Polydimethylsiloxane on the Oxygen Concentration of Oils at Various Temperatures

The effect of temperature on the oil oxygen concentration, tested in both soybean and olive oils with no added polydimethylsiloxane (PDMS), showed that the oxygen concentration increased with temperature to approximately 100 °C. Above 100 °C, the oxygen concentration abruptly decreased. This change was attributed to the balance between the rates of oxygen uptake and consumption by oil oxidation, which favored oxygen consumption over uptake at temperatures above 100 °C. The addition of 100 ppb PDMS to soybean oil, enough to form a continuous layer over the surface of the oil, reduced the oxygen concentration when compared to a soybean oil control containing no added PDMS at temperatures ranging from 93 to 180 °C; thus suggesting an oxygen barrier effect of PDMS. The accumulation of PDMS at the air–oil interface in soybean oil held at 180 °C was determined by comparing the oil’s internal temperature and the apparent surface temperature. A decrease in the apparent surface temperature while the oil was held at a constant internal temperature was attributed to a change in the emissivity of the surface as a consequence of the accumulation of PDMS in the air–oil interface. The presence of PDMS at the air–oil interface was confirmed for 100 ppm of PDMS, a concentration greater than the concentration necessary to form a monolayer of PDMS on the oil surface.     

Molecular Partners of Escherichia coil Transcriptional Modulator AidB

The AidB protein is involved in the adaptive response to DNA alkylation damages in Escherichia coli. Functional proteomic experiments were designed to elucidate AidB biological functions in the presence and in the absence of methyl methanesulfonate as methylating agent. Several proteins were identified in both conditions and according to their reported biological activities, the inter-actors were grouped into three different functional categories： stress response, energetic metabolic pathways and nucleic acid metabolism. Particularly, the interaction between AidB and UvrA, a member of the UvrABCD nucleotide excision system, suggested a new interesting putative role for AidB.     

Parameter Sweep Workflows for Modelling Carbohydrate Recognition

Carbohydrate recognition is a phenomenon critical to a number of biological functions in humans. Understanding the dynamic behaviour of oligosaccharides should help in the discovery of the mechanisms which lead to specific and selective recognition of carbohydrates by proteins. Computer programs which can provide insight into such biological recognition processes have significant potential to contribute to biomedical research if the results of the simulation can prove consistent with the outcome of conventional wet laboratory experiments. In order to validate these simulation tools and support their wider uptake by the bio-scientist research community, high-level easy to use integrated environments are required to run massively parallel simulation workflows. This paper describes how the ProSim Science Gateway, based on the WS-PGRADE Grid portal, has been created to execute and visualise the results of complex parameter sweep workflows for modelling carbohydrate recognition.     

The language of demand/withdraw: Verbal and vocal expression in dyadic interactions.

Associations between vocally expressed emotional arousal, influence tactics, and demand/withdraw behavior were examined in a treatment-seeking sample of 130 seriously and stably distressed, married, heterosexual couples and in a community sample (N = 38) of 18 married heterosexual and 20 dating heterosexual couples. Fundamental frequency was used to measure emotional arousal, and computational linguistics were used to measure influence tactics. Higher levels of demand/withdraw behavior were associated with greater use of manipulative and controlling influence tactics, higher levels of emotional arousal, and less frequent use of cooperative and compromising influence tactics. Overall, demanders tended to express more arousal and to use more influence tactics than withdrawers. Both influence tactics and emotional arousal were uniquely associated with demand/withdraw behavior. Implications of results are discussed for refining theories of demand/withdraw interaction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Parenting at risk: New perspectives, new approaches.

In this lead paper for this special section, we advance the perspective that new insights into parenting at risk can be gained by focusing on the dynamic emotional processes that occur during parent–child exchanges, with special emphasis on parental emotions as experienced and their regulation of emotion and underlying cognitions, as well as the role of developmentally rooted cognitions in shaping these associations. We discuss the very few but germinal studies that embody this perspective and introduce work in this section that examines emotion dynamics during parenting in real time. We believe this perspective will move us beyond static conceptualizations of parenting at risk, broadens our understanding of parenting as a process, and accelerates our ability to identify the essential targets of intervention when parenting is at risk. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Transforming shortcomings into opportunities: Can market incentives solve Lebanon's energy crisis?

Over the past decades Lebanon's energy sector has been largely ignored and this has led to high economic and environmental costs. The sector is characterized by electricity poverty, an expanding and mainly unregulated transport sector and a lack of energy savings spanning through all sectors of the economy. Recently, the Government of Lebanon has committed to increase the share of renewable energy to 10% of the total energy supply by 2013 and to 12% by the year 2020; it also aims at reducing energy consumption by 6% by the year 2013. This paper aims at contributing to the formulation of a more comprehensive energy strategy for Lebanon by analyzing the recent changes in policy direction and by recommending legal, regulatory and policy measures in order to transform current shortcomings into opportunities allowing the country to become a regional ‘success story’ in the deployment of renewable energy and energy efficiency.     

A longitudinal study of the social and academic competence of economically disadvantaged bilingual preschool children.

This longitudinal study was conducted to gain understanding of the social–emotional and academic development of economically disadvantaged bilingual preschool children. In Study 1, the authors combined cognitive, psychosocial, and cultural-linguistic factors to determine profiles of social competence as measured by peer play. A person-centered analysis of 207 Hispanic American preschoolers (ages 4 and 5 years) yielded 6 distinct profiles, 2 of which were socially competent and 1 of which was vulnerable. Findings revealed profile differences in social competence and a significant relationship between bilingualism and social–emotional development. In Study 2, the authors determined which profiles were associated with later academic achievement and growth of English proficiency. Findings indicated a significant relationship of early social–emotional development to later academic success and English acquisition, highlighting the role of bilingualism. (PsycINFO Database Record (c) 2011 APA, all rights reserved)