| 1. |
- Aneheim, Emma, 1982, et al.
(author)
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Development of a Novel GANEX Process
- 2010
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In: ACS Symposium Series. - Washington, DC : American Chemical Society. - 1947-5918 .- 0097-6156. ; 1046, s. 119-130
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Conference paper (peer-reviewed)abstract
- The waste from nuclear power plants has to be isolated from man and his environment for about 100,000 years to be considered safe. It has been suggested that if the long-lived actinides could be separated from the spent fuel and transmuted, the isolation time could be shortened to about 1,000 years. This, however, requires selective separation of parts of the waste. The partitioning for transmutation research in Europe has for the major part taken place within several European Union Framework Programmes. Within the projects NEWPART, PARTNEW and EUROPART a process scheme for the partitioning of nuclear waste from the PUREX process was developed. The scheme includes the DIAMEX, SANEX and SESAME-processes among which both the DIAMEX and SANEX process has been successfully tested on genuine spent fuel. However, in the latest EU Project ACSEPT, which started in 2008, another approach towards partitioning is being investigated. This is the so called GANEX (Group ActiNide EXtraction) process. In the GANEX process all the actinides in the dissolved spent fuel are extracted as a group and hence separated from the lanthanides as well as the rest of the fission and corrosion/activation products. A novel GANEX process has been developed at Chalmers university of Technology in Sweden. This new process utilizes the properties of already well known extractants by combining BTBP and TBP into one solvent. The system is able to extract U, Np, Pu and Am from strong nitric acid and simultaneously separate these elements from the lanthanides. This is done with sufficiently high distribution ratios and separation factors without the need for any redox control.
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| 2. |
- Antonio, Capezza, et al.
(author)
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Advances in the use of protein-based materials: towards sustainable naturally sourced absorbent materials
- 2019
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In: American Chemical Society Symposium Series (ACS). - : American Chemical Society (ACS). - 0097-6156 .- 1947-5918. ; 7:5
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Journal article (peer-reviewed)abstract
- Superabsorbent polymers (SAPs) are important in the health-care and personal care industries. Products like bed pads and diapers improve the comfort and sanitary conditions for people all over the world, with SAPs reaching yearly production volumes of ca. 2 million tons. However, recent sustainability issues have questioned the high negative footprint of polymers from nonrenewable resources. Biomacromolecules, especially when functionalized, have properties that make them an attractive alternative for the production of biobased SAPs. Proteins are a particularly interesting alternative due to their high variability and because of their relatively low price, being available as side streams from the agricultural industries. Due to the harsh extraction conditions, these side stream proteins are not competing with the food industry and alternative source-effective uses are advantageous in a circular bioeconomy. As the properties of a SAP material come from a combination of neutralized functional groups to promote polar liquid uptake and intermolecular cross-links to prevent dissolution, proteins offer unique opportunities due to their variability in polymerization. An increased understanding of the protein characteristics and how these can be tuned through functionalization is therefore a prerequisite for the successful development of a commercial biobased SAP that utilizes industrial and nontoxic wastes toward more sustainable products. This review focuses on proteins as biomacromolecules with relevant characteristics for superabsorbent functions, and discusses the opportunities that they may offer toward sustainable SAPs utilizing nontoxic chemicals and following the green chemistry principles.
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| 3. |
- Berglund, Per, et al.
(author)
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Enantiorecognition of Chiral Acids by Candida rugosa Lipase : Two Substrate Binding Modes Evidenced in an Organic Medium
- 2001
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In: Applied Biocatalysis in Speciality Chemicals and Pharmaceuticals. - : American Chemical Society (ACS). - 0841236798 ; 776, s. 263-273
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Conference paper (peer-reviewed)abstract
- We have identified the existence of different modes of binding the enantiomers of 2-methyl-branched carboxylic acids to a lipase active site by rational substrate engineering. Similar to hydrolysis, previously investigated, we have now evidence for differential binding modes in the Candida rugosa lipase-catalyzed esterifications in cyclohexane. The relevance of considering two different binding modes to understand lipase enantiorecognition is demonstrated by introducing bulky substituents on a chiral carboxylic acid which impose a different orientation of the substrate acyl chain in the active site of Candida rugosa lipase. With this substrate engineering approach based on molecular modeling it is thus possible to markedly alter the enantioselectivity of the lipase. Examples from hydrolysis and new results from esterifications in an organic solvent are presented and discussed.
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| 4. |
- Bidleman, TF, et al.
(author)
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Air-soil and air-water exchange of chiral pesticides
- 2003
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In: ENVIRONMENTAL FATE AND EFFECTS OF PESTICIDES Book Series: ACS SYMPOSIUM SERIES. - 0097-6156. ; 853, s. 196-225
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Journal article (peer-reviewed)abstract
- The enantiomers of chiral pesticides are often metabolized at different rates in soil and water, leading to non-racemic residues. This paper reviews enantioselective metabolism of organochlorine pesticides (OCPs) in soil and water, and the use of enantiomers to follow transport and fate processes. Residues of chiral OCPs and their metabolites are frequently non-racemic in soil, although exceptions occur in which the OCPs are racemic. In soils where enantioselective degradation and/or metabolite formation has taken place, some OCPs usually show the same degradation preference; e.g. depletion of (+)trans-chlordane (TC) and (-)cis-chlordane (TC), and enrichment of the metabolite (+)heptachlor exo-epoxide (HEPX). The selectivity is ambivalent for other chemicals; preferential loss of either (+) or (-)o,p'-DDT and enrichment of either (+) or (-)oxychlordane (OXY) occurs in different soils.Non-racemic OCPs are found in air samples collected above soil which contains non-racemic residues. The enantiomer profiles of chlordanes in ambient air suggests that most chlordane in northern Alabama air comes from racemic sources (e.g. termiticide emissions), whereas a mixture of racemic and non-racemic (volatilization from soil) sources supplies chlordane to air in the Great Lakes region. Chlordanes and heptachlor exo-epoxide (HEPX) are also non-racemic in arctic air, probably the result of soil emissions from lower latitudes.The (+) enantiomer of alpha-hexachlorocyclohexane (alpha-HCH) is preferentially metabolized in the Arctic Ocean, arctic lakes and watersheds, the North American Great Lakes and the Baltic Sea. In some marine regions (Bering and Chukchi seas, parts of the North Sea) the preference is reversed and (-)alpha-HCH is depleted. Volatilization from seas and large lakes can be traced by the appearance of non-racemic alpha-HCH in the air boundary layer above the water. Estimates of microbial degradation rates for alpha-HCH in the eastern Arctic Ocean and an arctic lake have been made from the enantiomer fractions (EFs) and mass balance in the water column. Apparent pseudo first-order rate constants in the eastern Arctic Ocean are 0.12 y(-1) for (+)alpha-HCH 0.030 y(-1) for (-)alpha-HCH, and 0.037 y(-1) for achiral gamma-HCH. These rate constants are 3-10 times greater than those for basic hydrolysis in seawater. Microbial breakdown may compete with advective outflow for long-term removal of HCHs from the Arctic Ocean. Rate constants estimated for the arctic lake are about 3-8 times greater than those in the ocean.
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| 5. |
- Chimuka, Luke, et al.
(author)
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Application of membrane-based extraction techniques to food and agricultural samples
- 2006
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In: Modern extraction techniques; food and agricultural samples (ACS symposium series). - 0097-6156. - 9780841239401 - 0841239401 ; 926, s. 149-162
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Book chapter (other academic/artistic)abstract
- The use of membrane-based extractions are increasingly seen as offering an alternative to conventional sample preparation procedures in analysis of chemical species in both food and agricultural samples. In this article, emphasis is placed on the attractiveness of membrane based extraction techniques to a variety of food and agricultural samples such as circulating nutrient solutions, fruit juices, fruits, beverages, vegetables, food oils and others. Examples of membrane based applications demonstrating how selective these techniques are even for food and agricultural samples are given.
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| 6. |
- Clymans, Wim, et al.
(author)
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Amorphous Silica Preservation in an Anthropogenic Soil: An Explorative Study of "Plaggen" Soils
- 2013
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In: Progress in Silicones and Silicone-Modified Materials. - 0097-6156. ; 1154, s. 3-14
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Conference paper (peer-reviewed)abstract
- Amorphous Silica (ASi) is present in considerable amounts in most soils and serves as a (micro-)nutrient for many plants. However, our understanding of the response of this important nutrient pool to human or natural disturbances is still very limited. One of the reasons for this is the long time scales involved. This explorative study focuses on the effect of a historical agricultural system, called plaggen management, that was applied on sandy areas in Belgium, the Netherlands and Germany over a period of ca. 1000 yrs on ASi dynamics. The system was designed to maintain high nutrient levels (including C and Si) on arable fields through the addition of mixtures rich in animal manure and vegetation residues. The continuous addition of ASi over such a long time period allows to study if and to what extent ASi is preserved in such a soil system and how Si addition affects the build-up and availability of ASi pools. We quantified ASi pools (Na2CO3 extraction) in a soil profile with plaggen application, and a reference soil without plaggen application. Other measured soil properties were soil organic carbon (SOC) and grain size distribution. There was an important SOC (+20%) and ASi accumulation (+70%) and preservation at the plaggen site. Si losses from the soil column through leaching and crop harvest might thus be restricted by application of organic residue and Si fertilisation to maintain sustainable nutrient concentrations in the topsoil. Net C and Si accumulation rates were 45 kg C ha(-1) y(-1) and 77 kg SiO2 ha(-1) y(-1) respectively, not accounting for the removal of ASi through plant uptake nor for the mineralisation of part of the SOC. The vertical distribution of ASi within the profile, suggests that, contrary to SOC, most of the added ASi has remained stably stored in the soils and that only a smaller, labile pool was removed, most likely through dissolution rather than through plant uptake. Our results indicate that ASi addition leads to a build-up of Si pools in these sandy soils. While this results in increased Si availability, this effect is limited because most ASi remains stored for long time spans. To consolidate our preliminary research results, to answer unresolved questions and to validate proposed hypotheses, future research should: (I) collect additional profiles with higher vertical resolution; (2) include other Si fractions; (3) analyse the relationship between ASi and SOC to better understand the coupling of the ASi and C cycles; (4) develop a modelling approach that would allow one to investigate how ASi pools in soils may respond to future changes.
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| 7. |
- da Cruz Francisco, José, et al.
(author)
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Isolation of alkylresorcinols: Classical and supercritical CO2 extraction methods
- 2006
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In: Modern Extraction Techniques: Food and Agricultural Samples (ACS Symposium). - 0097-6156. - 9780841239401 - 0841239401 ; 926, s. 51-61
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Book chapter (other academic/artistic)abstract
- This chapter focuses on the use of different methods for isolation of alkylresorcinols. Alkylresorcinols are members of a lipid group called non-isoprenoid phenolic lipids. Different aspects of the extraction by classical methods and supercritical CO2 are discussed. Supercritical CO2 extraction of alkylresorcinols from rye bran is discussed for the first time. As compared to the classical extraction methods, supercritical CO2 gives higher yields and it allows the separation of the crude extrac into long- and short-chain alkylresorcinol homologues.
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| 8. |
- Dekker, Teun
(author)
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Getting Them Where They Live-Semiochemical-Based Strategies To Address Major Gaps in Vector Control Programs: Vectrax, SPLAT BAC, Trojan Cow, and SPLAT TK
- 2018
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In: ACS Symposium Series. - Washington, DC : American Chemical Society. - 0097-6156. ; 1289, s. 101-152
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Conference paper (peer-reviewed)abstract
- For most of the company's history, ISCA Technologies' main focus for semiochemical research has been on the development of solutions using these behavior-modifying chemicals to manage agricultural insect pests. However, in recent years, ISCA scientists have expanded their research into another field: management of hematophagous vectors of disease, including mosquitoes, responsible for transmitting such widespread and devastating diseases as malaria, dengue, lymphatic filariasis, Zika, and West Nile virus; and ticks, which transmit Lyme disease, anaplasmosis, and babesiosis, among others. Discussed herein are four examples of semiochemical-based technologies utilizing the attract-and-kill approach to suppress populations of disease-carrying arthropods: Vectrax, SPLAT BAC, Trojan Cow, and SPLAT TK. Each of these formulations is being developed to achieve effective control of vector populations by a different mechanism, by manipulating a different aspect of the target vector's behavior. Vectrax is a flowable formulation comprising a blend of floral attractants and phagostimulants, intended to attract adult sugar-seeking mosquitoes of any species, sex, or physiological status. Vectrax is designed to be blended with the user's insecticide of choice just prior to application, a process comprised of tank-mixing. As a larvicide formulation, SPLAT BAC targets mosquitoes at the larval stage of their life cycle, before they mature into adults capable of breeding or transmitting disease, incorporating two bacterial control agents, Bacillus thuringiensis israelensis and Bacillus sphaericus, in ISCA's controlled release SPLAT technology (Specialized Pheromone & Lure Application Technology). If the development of this product is successful, the controlled-release matrix will enable SPLAT BAC to be applied to prospective larval habitats preemptively before a rain event, a major advantage over previously developed larvicides. Trojan Cow is designed to manipulate the host-seeking behavior of anthropophilic (human-preferring) mosquitoes, by applying a scent cue associated with humans to livestock animals treated with the deworming medication, ivermectin. This compound, which benefits the treated animal by reducing infestation by helminthic parasites, is lethal to both the malaria vector (Anopheles mosquitoes) and the parasite (Plasmodium spp.). SPLAT TK targets the deer tick, Ixodes scapularis, the vector of Lyme disease the most common vector-borne illness in the U.S. by sustaining the controlled release of arrestment pheromones along the borders of areas where contact between the tick vector and its host is most likely to occur (hiking trails, backyards, etc.). In field studies, these arrestment pheromones caused host-seeking ticks to approach and cluster around point sources of SPLAT TK, containing a tank-mixed acaricide, creating the opportunity to eliminate them before they can attach to a human or animal host. Adoption of effective semiochemical-based technologies like those whose research and development are described here could change the way arthropods vectors of disease are managed around the world, providing safer, more effective tools for their control.
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| 9. |
- Eren, Baran, et al.
(author)
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Contamination Issues in Ambient Pressure Experiments
- 2021
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In: Ambient Pressure Spectroscopy in Complex Chemical Environments. - Washington, DC : American Chemical Society. - 0097-6156 .- 1947-5918. - 9780841298125 - 9780841298118 ; 1396, s. 267-295
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Book chapter (peer-reviewed)abstract
- Contamination is the most common and arguably the most significant problem scientists are facing in experimental surface science research that is practiced in the presence of gases. It is fair to say that contamination problems are often worse with ambient pressures compared to conventional experiments in vacuum. It is one of the main reasons for poor reproducibility in this field and in relevant basic and applied research fields like heterogeneous catalysis and electrochemistry. Whilst some type of contaminants are more innocent and only hinder quantitative analysis, some are harmful as they change the outcome of the experiments. In this chapter, the potential sources of contamination are summarized and some solutions are suggested. Examples of commonly observed contaminants such as hydrocarbons, oxygenated hydrocarbons, and adsorbed species of traces gases are presented. The scope of this chapter is restricted to ambient pressure x-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy studies on single crystal surfaces, but similar problems exist on other sample surfaces or with other techniques such as x-ray absorption spectroscopy and sum frequency generation spectroscopy.
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| 10. |
- Erlanson-Albertsson, Charlotte, et al.
(author)
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Thylakoids Promote Satiety in Healthy Humans. Metabolic Effects and Mechanisms
- 2012
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In: ACS Symposium Series. - 0097-6156. ; 1093, s. 521-531
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Conference paper (peer-reviewed)abstract
- Thylakoids are the photosynthetic membranes of the chloroplasts in green leaves. Thylakoids have been found to promote satiety when added to food, both in animal experimental models and in human. The thylakoids act through inhibition of lipase-colipase catalysed hydrolysis of triacylglycerol, which is the main dietary fat component. The mechanism for inhibition is either a binding of thylakoids to lipase-colipase, which thereby prevents to act as a lipolytic enzyme complex or binding of thylakoids to the triacylglycerol droplet, thereby hindering the access of lipase-colipase to its substrate. Thylakoids consist of proteins and lipids in a membrane structure containing various protein-bound pigments. The thylakoid membranes are fairly resistant to gastrointestinal breakdown, which may be an important property to explain the satiety promoting effect. Satiety is promoted through the release of cholecystokinin, a gastrointestinal hormone that causes an inhibition of gastric emptying and stimulation of satiety mechanism in the brain. The hunger hormone ghrelin is suppressed as well as insulin. In human short-term experiments thylakoids added to food promote satiety signalling. In long-term a reduced body fat mass was observed.
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