Liquid and vapor phase adsorption of chlorinated volatile organic compounds on hydrophobic molecular sieves

This work focused on the potential application of various hydrophobic molecular sieves for the sorption of four model chlorinated volatile organic compounds (CVOCs, i.e., chloroform, trichloroethylene, tetrachloroethylene, and carbon tetrachloride) from dilute liquid water streams.

Results obtained thus far have shown that silicalite-1 has a high affinity for these CVOCs, higher in fact than Centaur^® activated carbon, used as a benchmark in this study. Loading results for trichloroethylene from both liquid and vapor phase indicated that the liquid phase did not penetrate the pores of silicalite-1, while the solution did penetrate the pores of Centaur^® and a dealuminated NaY used for comparison.

Finally, three definitions from the literature for the “hydrophobicity” of molecular sieves were considered. An alternative definition for hydrophobicity is introduced here, which is easy to determine and is based on water retention.     

Technology development for roll-to-roll production of organic photovoltaics

In order to reach the objective of low-cost, large area organic photovoltaic systems, we build up a knowledge base concerning the influence of process conditions on the performance of polymer solar cells. A large area solar cell module, with roll-to-roll coated PEDOT:PSS and photoactive layers (based on P3HT:[C60]PCBM blend) on a flexible substrate, has been demonstrated. Both the PEDOT:PSS and photoactive layer were deposited by slot die coating. A non-chlorinated solvent was used for the deposition of the photoactive blend. The flexible solar cell module illustrated a power conversion efficiency of 0.7% under AM 1.5 conditions. Methods to further improve the technological process are proposed.     

Catalytic organosolv fractionation of willow wood and wheat straw as pretreatment for enzymatic cellulose hydrolysis

BACKGROUND: Ethanol‐based organosolv fractionation of lignocellulosic biomass is an effective pretreatment technology for enzymatic cellulose hydrolysis to produce sugars and lignin within a biorefinery. This study focuses on the catalytic effect of H₂SO₄, HCl, and MgCl₂ on organosolv pretreatment of willow wood and wheat straw. RESULTS: The use of catalysts improved fractionation of both feedstocks. The maximum enzymatic cellulose digestibility obtained was 87% for willow wood (using 0.01 mol L^?1 H₂SO₄ as catalyst) and 99% for wheat straw (0.02 mol L^?1 HCl). Non‐catalytic organosolv fractionation at identical conditions resulted in 74% (willow wood) and 44% (wheat straw) glucose yield by enzymatic hydrolysis. Application of catalysts in organosolv pretreatment was particularly effective for wheat straw. The influence of the acid catalysts was found to be primarily due to their effect on the pH of the organosolv liquor. Acid catalysts particularly promoted xylan hydrolysis. MgCl₂ was less effective than the acid catalysts, but it seemed to more selectively improve delignification of willow wood. CONCLUSION: Application of catalysts in organosolv pretreatment of willow wood and wheat straw was found to substantially improve fractionation and enzymatic digestibility. The use of catalysts can contribute to achieving maximum utilization of lignocellulosic biomass in organosolv‐based biorefineries. Copyright © 2011 Society of Chemical Industry     

Similar but Not the Same: First Kinetic and Structural Analyses of a Methanol Dehydrogenase Containing a Europium Ion in the Active Site

Since the discovery of the biological relevance of rare earth elements (REEs) for numerous different bacteria, questions concerning the advantages of REEs in the active sites of methanol dehydrogenases (MDHs) over calcium(II) and of why bacteria prefer light REEs have been a subject of debate. Here we report the cultivation and purification of the strictly REE‐dependent methanotrophic bacterium Methylacidiphilum fumariolicum SolV with europium(III), as well as structural and kinetic analyses of the first methanol dehydrogenase incorporating Eu in the active site. Crystal structure determination of the Eu‐MDH demonstrated that overall no major structural changes were induced by conversion to this REE. Circular dichroism (CD) measurements were used to determine optimal conditions for kinetic assays, whereas inductively coupled plasma mass spectrometry (ICP‐MS) showed 70 % incorporation of Eu in the enzyme. Our studies explain why bacterial growth of SolV in the presence of Eu³⁺ is significantly slower than in the presence of La³⁺/Ce³⁺/Pr³⁺: Eu‐MDH possesses a decreased catalytic efficiency. Although REEs have similar properties, the differences in ionic radii and coordination numbers across the series significantly impact MDH efficiency.     

RevErbα Preferentially Deforms DNA by Induced Fit

Using free‐energy simulations, we have shown that RevErbα‐induced DNA deformation preferentially occurs by induced fit rather than by conformational selection, even though the DNA is only slightly distorted in the complex. Our study shows that information on the sequence of binding events is needed to establish whether conformational selection or induced fit is operative, and that the presence of multiple apo‐state structures might not be enough to distinguish between these binding models.     

Technologies for the study of hydropeaking impacts on fish populations: Applications,advantages, outcomes,and future developments

Dam construction and streamflow regulation are increasing throughout the world, with impacts in impounded aquatic ecosystems. Hydropower dams, some of them causing a phenomenon called “hydropeaking” during their operation, are known for having a variety of impacts on downstream aquatic biota, particularly fish, and respective habitat. This can result in significant changes, from the community (e.g., fish assemblage structure) to the individual level (e.g., physiological and behavioural adjustments). Researchers and managers involved in the assessment of hydropeaking impacts must be resourceful and use methods that allow their precise evaluation, from large to fine-scale habitat and biological responses. In the last decades, technological advances allowed for the development of techniques and instrumentations that are increasingly being used in hydropeaking impact and mitigation assessments. This paper aims to provide a review, to researchers and managers interested in this field, of some of the most innovative methods and techniques, involving technology, that are available to study hydropeaking effects on downstream ecosystem, particularly from a fish perspective. We discuss the fundamentals behind such techniques, their advantages, and disadvantages, while also providing practical examples of their application and of the type of results that can be obtained. We finish by discussing some of the shortcomings of these methods and how related technology can evolve to solve current limitations.     

Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle

The objectives of this study were to reveal molecular structures of protein among different types of the dried distillers grains with solubles (100% wheat DDGS (WDDGS); DDGS blend1 (BDDGS1, corn to wheat ratio 30:70%); DDGS blend2 (BDDGS2, corn to wheat ratio 50:50 percent)) and different batches within DDGS type using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). Compared with BDDGS1 and BDDGS2, wheat DDGS had higher (p < 0.05) peak area intensities of protein amide I and II and amide I to II intensity ratio. Increasing the corn to wheat ratio form 30:70 to 50:50 in the blend DDGS did not affect amide I and II area intensities and their ratio. Amide I to II peak intensity ratio differed (p < 0.05) among the different batches within WDDGS and BDDGS1. Compared with both blend DDGS types, WDDGS had higher α-helix and β-sheet ratio (p < 0.05), while α-helix to β-sheet ratio was similar among the three DDGS types. The α-helix to β-sheet ratio differed significantly among batches within WDDGS. Principal component analysis (PCA) revealed that protein molecular structures in WDDGS differed from those of BDDGS1 and between different batches within BDDGS1 and BDDGS2. The α-helix to β-sheet ratios of protein in all DDGS types had an influence on availability of protein at the ruminal level as well as at the intestinal level. The α-helix to β-sheet ratio was positively correlated to rumen undegraded protein (r = 0.41, p < 0.05) and unavailable protein (PC; r = 0.59, p < 0.05).     

Application of metal triflate catalysts for the trans-esterification of Jatropha curcas L. oil with methanol and higher alcohols

This paper describes an experimental study on the application of metal triflate salts for the (trans‐) esterification of fatty esters (triolein, methyl oleate, methyl linoleate), fatty acid (oleic acid), as well as Jatropha curcas L. oil with methanol and higher alcohols (ethanol, n‐propanol, iso‐propanol, iso‐butanol, tert‐butanol). The effect of the metal type (scandium, bismuth, aluminium, lanthanum, copper, zinc) and process conditions on reaction performance were evaluated. Highest conversions were obtained with Al(OTf)₃. Reaction of triolein with methanol gave 99 mol% conversion at 165 °C for 1 h and the main product was the methyl ester. In addition, partial methoxylation of the carbon–carbon double bonds in the fatty acid chains was observed, though their fraction in the mixture was less than 20 mol%. The trans‐esterification reaction was also successfully performed using higher alcohols, giving >95 % conversions for ethanol, n‐propanol, iso‐propanol and iso‐butanol, whereas tert‐butanol was not reactive. For the reaction of oleic acid with methanol, quantitative esterification, partial methoxylation of the carbon–carbon double bonds and the formation of small amounts of a lactone was observed. The methodology using Al(OTf)₃ was successfully performed on the trans‐esterification reaction of JO (FFA content of 2.1 wt%) with various alcohols. Key properties (viscosity, pour point and cloud points) of the (branched) Jatropha esters were determined. The best cold‐flow properties were obtained for the iso‐propyl esters of JO, with cloud point and pour point of ?3 and ?24 °C, respectively.     

Quaternized microgels as soft templates for polyelectrolyte layer-by-layer assemblies

A cationic microgel with quaternized amine groups was prepared and used as a soft template for layer-by-layer (LbL) assemblies. The presence of quaternized amine groups inside the microgels was necessary to prevent rearrangements and subsequent bridging between the coated microgels, which were observed for the precursor microgels containing protonated primary amino groups. Sequentially, negatively charged polyelectrolyte poly(sodium styrene sulfonate) (PSS) and positively charged polyelectrolyte poly(diallyldimethylammonium chloride) (PDADMAC) were added to a suspension of quaternized microgels. This leads to an odd-even effect with respect to particle size and surface charge of the formed microgel–polyelectrolyte complexes (MPECs). MPECs with an even number of layers exhibit positive surface charge due to PDADMAC as the outermost layer and are larger compared to complexes with an odd number of layers, which are negatively charged having PSS in the outermost layer. Taking into account previous results (Macromolecules,2009,42, 1229), these observations show that electrostatic interactions are the major force for the odd-even effect in polyelectrolyte multilayers on microgels: the cationic groups of PDADMAC compete with the cationic moieties of the microgel for binding with the sulfonate groups of PSS. Concomitantly, a fluctuating size of the MPECs is induced by an osmotic pressure modulation within the microgel. In contrast, surface tension effects invoked by a possible varying hydrophilicity of the different terminal layers are negligible.