bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical and pharmaceutical applications of packed‐column supercritical fluid chromatography
Authors: Abbott Eric , Veenstra Timothy D. , Issaq Haleem J. 
Published: March 2008

AbstractPacked‐column supercritical fluid chromatography (pSFC) is a fast separation technique that combines the properties of HPLC and GC. pSFC with carbon dioxide as the mobile phase and packed silica column as the stationary phase possesses the properties of normal phase mechanism; however, the addition of modifiers to the mobile phase allows the separation of relatively polar compounds. In spite of its many positive attributes, pSFC has not been widely used in areas such as proteomics, where methods such as HPLC dominate. Packed column SFC has been extensively used in clinical and pharmaceutical laboratories, especially for separation of nonpolar and chiral drugs. This review will discuss recently published applications of pSFC, with a specific focus on its advantages and limitations for the analysis of pharmaceuticals with varying chemical properties.
Balance between polyunsaturated fatty acids and antioxidants in nutrition
Authors: Kamal‐Eldin Afaf , Pickova Jana 
Published: March 2008

AbstractIt is recommended that humans increase their consumption of omega‐3 polyunsaturated fatty acids (PUFA) because of many nutritional advantages. However, the oxidative instability of these fatty acids poses a problem regarding the sensory and nutritional quality of foods. It is clear that antioxidants need to be added to stabilize these lipids during food processing and storage, as well as to provide the body with enough antioxidant power to counteract any oxidative stress resulting from the increased intake of PUFA. However, we need more knowledge regarding the levels of antioxidant required for food stability and nutritional adequacy as well as the nature of antioxidant oxidation products and their toxicological significance.
Analysis of a moving boundary value problem arising in biofilm modelling
Authors: Szomolay Barbara 
Published: March 2008

AbstractWe consider a moving boundary value problem associated with a 1‐D biofilm model proposed by Szomolay et al. (Environ. Microbiol. 2005; 8:1186–1191). The new model includes growth and detachment which make it more realistic in a biofilm setting. Global existence and properties of solutions are shown using the method of characteristics. We also study the existence of the corresponding steady‐state solutions and prove their uniqueness for small doses of biocide. In addition, sufficient conditions for the existence of trivial/nontrivial steady states are established. Copyright © 2008 John Wiley & Sons, Ltd.
Exponential convergence of the h–p version BEM for mixed boundary value problems on polyhedrons
Authors: Holm H. , Maischak M. , Stephan E. P. 
Published: March 2008

AbstractWe analyze the h–p version of the boundary element method for the mixed Dirichlet–Neumann problems of the Laplacian in polyhedral domains. Based on a regularity analysis of the solution in countably normed spaces, we show that the boundary element Galerkin solution of the h–p version converges exponentially fast on geometrically graded meshes (up to an additional term that converges algebraically with arbitrary high order). Copyright © 2008 John Wiley & Sons, Ltd.
A multilevel programming approach to decentralized (or hierarchical) resource allocation systems
Authors: Mitiku Semu 
Published: March 2008

AbstractIn many decision processes there is a hierarchy of decision‐makers and decisions are taken at different levels in this hierarchy. In business (and many other practical activities) decision making has changed over the last decades. From a single person (the boss!) and a single criterion (e.g. profit), decision environments have developed increasingly to become multi‐person and multi‐criteria and even multi‐level (or hierarchical) situations. In organization with hierarchical decision systems, the sequential and preemptive nature of the decision process makes the problem of selecting an optimum strategy and action very different from the usual operations research methods. Therefore, a multilevel programming approach is considered in modeling such problems. In particular a three‐level mathematical programming model has been proposed for an optimal resource allocation problem in Ethiopian universities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cluster synchronization, switching and spatiotemporal coding in a phase oscillator network
Authors: Orosz Gábor , Ashwin Peter , Wordsworth John , Townley Stuart 
Published: March 2008

AbstractA network of five globally‐coupled identical phase oscillators is considered. Cluster states consisting of two synchronized pairs of oscillators and one singleton are investigated. Forcing the system with non‐uniform constant inputs results in regular switches between cluster states. The resultant cyclic sequences of switches (spatiotemporal codes) are studied for different initial conditions and input configurations. Implications on information coding in neural systems are briefly discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the homogenization of the Buckley‐Leverett equation including trapping effects at the micro scale
Authors: Pop Iuliu Sorin , Schweizer Ben 
Published: March 2008

AbstractWe consider a simplified, one dimensional model for two‐phase (oil/water) flow in a porous medium. The medium consist of alternating homogeneous blocks separated by interfaces, where trapping effects may occur. Two effective models are derived in [2] and [7]. In this paper we show that the two models are equivalent. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mixing modeling for stochastic simulations of turbulent premixed flames
Authors: Stöllinger Michael , Heinz Stefan 
Published: March 2008

AbstractThe use of probability density function (PDF) methods for turbulent combustion simulations is very attractive because arbitrary finite‐rate chemistry can be exactly taken into account. However, many real flames involve a variety of mixing regimes (non‐premixed, partially‐premixed and premixed turbulent combustion), and the development of PDF methods for partiallypremixed and premixed turbulent combustion turned out to be a very challenging task. A promising way to extend the range of applicability of PDF methods to the fast flamelet chemistry of turbulent premixed flames is described here. Simulation results of three turbulent premixed flames demonstrate the suitability of this approach. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Does synergized pyrethrin applied over wetlands for mosquito control affect Daphnia magna zooplankton or Callibaetis californicus mayflies?
Authors: Lawler Sharon P , Dritz Deborah A , Johnson Catherine S , Wolder Mike 
Published: March 2008

AbstractBACKGROUND: Public health agencies may apply aerosolized synergized pyrethrin over wetlands repeatedly to control mosquitoes. This concerns wildlife managers because studies have shown the accumulation of pyrethroids, which are chemically similar to pyrethrin, in sediments in amounts that can be toxic to invertebrates. The authors tested whether repeated applications of synergized pyrethrin over wetlands caused mortality of two aquatic invertebrates: the zooplankton Daphnia magna Straus and a mayfly, Callibaetis californicus Banks. Fifteen wetland mesocosms were either exposed to repeated pyrethrin sprays or were protected by lids. Invertebrates in screened cages were placed in mesocosms before the fifth and eleventh spray, and directly into wetlands before spray 11. Six mesocosms were exposed to spray deposition. Caged adult mosquitoes were used to verify that sprays drifted over mesocosms. Sediments were analyzed for insecticide residues.RESULTS: There were no detectable effects of synergized pyrethrin on 36 h survival of Daphnia or mayflies, but most exposed adult mosquitoes died. Some exposed sediments yielded pyrethrin (≤34.5 ng g−1); most showed piperonyl butoxide (PBO) (≤14.9 ng g−1).CONCLUSIONS: Deposition of aerosolized 25% pyrethrin + 5% PBO may contaminate wetlands, but its application at rates used for mosquito control did not produce detectable effects on indicator species. Copyright © 2008 Society of Chemical Industry
The effect of substitution on the intramolecular hydrogen bonding in 3‐hydroxy‐propenethial
Authors: Raissi H. , Jalbout A. F. , Nasseria M. A. , Yoosefian M. , Ghiassi H. , Hameed A. J. 
Published: March 2008

AbstractThe intramolecular hydrogen bond strength of 3‐hydroxy‐propenethial (HPT) as well as the fluoro, chloro, bromo, and methyl derivatives were investigated at the B3LYP/6‐311++G**level of theory. Solvent‐based calculations (in water) for HPT and derivatives were also carried out. The nature of the intramolecular hydrogen bond existing within the molecular under investigation has been studied by means of the Bader theory of atoms in molecules (AIM) that is based upon the use topological properties in terms of the electron density. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Rapid full‐scale bioremediation of perchlorate in soil at a large brownfields site
Authors: Evans Patrick J. , Lo Ian , Moore Allen E. , Weaver William J. , Grove William F. , Amini Hassan 
Published: March 2008

AbstractThe former Bermite site north of Los Angeles, California, was used to manufacture various explosives and related products containing energetic compounds, including perchlorate. Remediation of perchlorate in site soil and groundwater is being conducted to meet regulatory requirements and allow planned redevelopment activities to proceed. The general approach to perchlorate remediation of shallow soil at the site includes excavation of affected soils followed by ex situ bioremediation. Glycerin was chosen for use as an electron donor because of its stability, safety, low cost, and regulatory acceptance. However, full‐scale bioremediation operation with glycerin initially resulted in inconsistent results despite consistent perchlorate biodegradation observed in treatability study microcosms. To eliminate the inconsistency and optimize the biotreatment process, additional studies were performed in the field on parallel tracks to determine crucial factor(s) that influenced inconsistent breakdown of perchlorate in site soils. Total Kjeldahl nitrogen (TKN) was determined to be a significant factor limiting perchlorate biodegradation. The addition of di‐ammonium phosphate (DAP) resulted in the consistent and complete perchlorate removal, generally within two weeks of incubation with a median destruction rate of about 200 μg/kg/day. Soil processing rates were gradually increased over the year, and, by the summer, approximately 2,000 to 2,500 tons of soil were being processed per day with a total of approximately 160,000 tons processed by the end of July. The total unit treatment cost for the process is about approximately $35/ton. The glycerin‐DAP process is playing a major role in the remediation of this 1,000‐acre former industrial site. © 2008 Wiley Periodicals, Inc.
Enhanced anaerobic bioremediation in a multicontaminant plume
Authors: Konzuk Julie S. , Duhamel Melanie , Major David W. , Repta Cory 
Published: March 2008

AbstractThe potential application of enhanced in situ bioremediation (EISB) for treatment of a plume containing high concentrations of 1,2‐dichloroethane (1,2‐DCA), as well as lower concentrations of other chlorinated ethanes, chlorinated methanes, and chlorinated ethenes was evaluated through the implementation of four field trials. The field trials confirmed that EISB is an effective technology for treating multiple contaminants, with estimated mass removal rates on the order of several kilograms per day and groundwater concentration reductions nearing 100 percent of the initial concentrations. The field trials also demonstrated that engineering controls could be effectively used to overcome potential inhibitions related to high concentrations of 1,2‐DCA. © 2008 Wiley Periodicals, Inc.
Managing residual contaminants—reuse and isolation case studies
Authors: Kostelnik Kevin M. , Clarke James H. 
Published: March 2008

AbstractContaminants remaining onsite after regulatory‐approved environmental remediation operations are complete represent continued risk to human health and the environment. Many sites require continued management efforts to: (1) protect the integrity of the engineered remedy/control, (2) limit the exposure of individuals to residual contamination by limiting reuse activities, (3) maintain ready access to accurate records/information, and (4) protect against vulnerabilities from intentional threats/actions. This article presents performance information from selected case studies to provide insight into various management approaches employed for addressing the risks associated with residual contaminants. The case studies involve sites remediated within the U.S. Comprehensive Environmental Response, Compensation, and Liability Act framework and illustrate two prevailing management approaches for addressing the risks. Sacrifice zones are sites that are purposefully isolated to prevent human access onto the property. Reuse sites provide limited access for specific use. © 2008 Wiley Periodicals, Inc.
Literature overview: Microbial metabolism of high molecular weight polycyclic aromatic hydrocarbons
Authors: Husain Saleha 
Published: March 2008

AbstractHigh molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) increase in hydrophobicity with increases in their molecular weight and ring angularity. Microbial strategies to deal with PAH hydrophobicity include biofilm formation, enzyme induction, and biosurfactants, the effect of which is variable on PAH metabolism depending on the surfactant type and concentration, substrate, and microbial strain(s). Aerobic HMW PAH metabolism proceeds via mineralization, partial degradation, and cometabolic transformations. Generally, bacteria and nonlignolytic fungi metabolize PAHs via initial PAH ring oxidation by dioxygenases to form cis‐dihydrodiols, which are transformed to catechol compounds by dehydrogenases and other mono‐ and dioxygenases to substituted catechol and noncatechol compounds, all ortho‐ or metacleaved and further oxidized to simpler compounds. However, lignolytic fungi form quinones and acids to CO2. This review discusses the pathways for HMW PAH microbial metabolism. © 2008 Wiley Periodicals, Inc.
Remediation and review: Developing groundwater strategy at the hanford site
Authors: Abbotts John , Weems Charles 
Published: March 2008

AbstractThe U.S. Department of Energy's (US DOE's) environmental challenges include remediation of the Hanford Site in Washington State. The site's legacy from nuclear weapons “production” activities includes approximately 80 square miles of contaminated groundwater, containing radioactive and other hazardous substances at levels above drinking water standards. In 1998, the U.S. General Accounting Office (US GAO), the auditing arm of Congress, concluded that groundwater remediation at Hanford should be integrated with a comprehensive understanding of the “vadose zone,” the soil region between the ground surface and groundwater. The US DOE's Richland Operations Office adjusted its program in response, and groundwater/vadose‐zone efforts at Hanford have continued to develop since that time. Hanford provides an example of how a federal remediation program can be influenced by reviews from the US GAO and other organizations, including the US DOE itself. © 2008 Wiley Periodicals, Inc.
The river Vecht fish community after rehabilitation measures: a comparison to the historical situation by using the river Biebrza as a geographical reference
Authors: Winter H. V. , Lapinska M. , de Leeuw J. J. 
Published: March 2008

AbstractSetting ecological goals for restoring fish communities in larger rivers is hampered by a lack of knowledge of the natural reference conditions. The lowland river Vecht has become highly regulated since 1850. Since the 1970s, measures have been taken to improve water quality followed by the construction of fishways along weirs in the 1990s to rehabilitate migration. We aim to assess the degree of deviation of the current fish community in the river from its pre‐regulation state. The assessment is based on a comparison with the less impacted river Biebrza in Poland as a geographical reference, involving a semi‐quantitative stepwise reconstruction based on available historic evidence. Electrofishing was used to describe the current quantitative species compositions of the fish communities in the rivers Vecht and Biebrza and historical records of the Vecht region were used to crosscheck the reconstructed fish community around 1850 after correcting for zoogeographical differences. Despite various rehabilitation measures, the deviation from the natural reference is still large. Currently, perch Perca fluviatilis and bream Abramis brama are much more abundant, and bleak Alburnus alburnus, white bream Blicca bjoerkna and most rheophilic species are far less abundant, than before. The main reasons for this deviation appears to be the present quality of the habitats and, for some species, the poor connectivity with the sea as well as with small tributaries. The approach used should be widely applicable to derive natural references, assess rehabilitation success or improve the ecological assessment of integrity as imposed by the European Water Framework Directive. Copyright © 2008 John Wiley & Sons, Ltd.
Downstream benthic responses to small dam removal in a coldwater stream
Authors: Orr Cailin H. , Kroiss Steve J. , Rogers Kristy L. , Stanley Emily H. 
Published: March 2008

AbstractIncreased awareness of the negative effects of dams combined with an aging dam infrastructure has led to an increase in dam removals. However, ecological responses of downstream biota to such actions are poorly understood. We examined the influence of a pair of small dam removals on downstream periphyton and macroinvertebrates in Boulder Creek, WI (USA). The dams were 180 m apart and both were removed on 9 July 2003. We monitored algae and macroinvertebrates as well as habitat characteristics for approximately 2 months before and after the removals upstream and downstream from the two dams, and continued our observations over a similar period (mid‐May to mid‐July) the following summer. After the removals, an initial release of sediment significantly increased the proportion of fine sediments in the downstream reach and buried benthic substrate. This burial led to a 60% reduction in chlorophyll in the downstream reach the week following removal, while concentrations increased in the upstream reference reach. Similarly, macroinvertebrate densities 2 weeks post‐removal were lower relative to pre‐removal densities and were associated with declines of ephemeropterans, trichopterans and dipterans. Examination of Trichoptera genera demonstrated substantial changes in this assemblage associated with diminished densities of the formerly dominant genus Brachycentrus. Algal and invertebrate populations increased in the weeks after the dam removal, but did not reach densities similar to the upstream reference reach. In the following year, both periphyton and invertebrate densities were lower in the downstream reach, suggesting a long‐term effect of the removal. Thus, effects of the dam removal were alternatively positive or negative over time, and indicate that the time scale of consideration has a strong effect on the interpretation of the consequences of this management activity. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of large woody debris on surface structure and aquatic habitat in forested streams, southern interior British Columbia, Canada
Authors: Chen Xiaoyong , Wei Xiaohua , Scherer Rob , Hogan Dan 
Published: March 2008

AbstractIt is well known that large woody debris (LWD) plays an important functional role in aquatic organisms' life. However, the influence of LWD on channel morphology and aquatic environments at watershed levels is still unclear. The relationships between wood and surface structure and aquatic habitat in 35 first through fifth order streams of southern interior British Columbia were investigated. Study streams in the channel networks of the study watersheds were classified into four size categories based on stream order and bankfull width: Stream size I: bankfull width was less than 3 m, Stream size II: 3–5 m, Stream size III: 5–7 m, Stream size IV: larger than 7 m. We found the number of functional pieces increased with stream size and wood surface area in stream sizes I, II and III (24, 28 and 25 m2/100 m2, respectively) was significantly higher than that in stream size IV (12 m2/100 m2). The contribution of wood pieces to pool formation was 75% and 85% in stream sizes II and III, respectively, which was significantly higher than those in stream size I (50%) and size IV (25%). Between 21% and 25% of wood pieces were associated with storing sediment, and between 20% and 29% of pieces were involved in channel bank stability in all study streams. Due to long‐term interactions, LWD in the intermediate sized streams (Size II and III) exhibited much effect on channel surface structure and aquatic habitats in the studied watersheds. Copyright © 2008 John Wiley & Sons, Ltd.
Soil seed banks of degraded riparian zones in southeastern Australia and their potential contribution to the restoration of understorey vegetation
Authors: Williams Laura , Reich Paul , Capon Samantha J. , Raulings Elisa 
Published: March 2008

AbstractAlthough soil seed banks are understood to be integral to the vegetation dynamics and restoration of many ecosystems, little is known of their role in riparian zones. In this study, we investigated soil seed banks of riparian zones of contrasting condition in an agricultural landscape and evaluated their potential to influence riparian restoration. We examined the composition and structure of germinable soil seed banks along lateral gradients from stream channels in both cleared and wooded riparian zones of three lowland creeks within the Goulburn Broken catchment in temperate southeastern Australia. Environmental correlates of soil seed bank characteristics and similarity to extant vegetation were also examined. We found an abundant and species‐rich soil seed bank mostly comprising propagules of perennial rushes and sedges and annual and perennial grasses with many species of annual forbs. While the majority of identifiable germinants and species were native, exotic species were common at all locations. Soil seed bank composition was relatively homogeneous among streams and along lateral gradients from the channel. Riparian condition (i.e. cleared or wooded), however, had a strong influence on soil seed bank composition and structure with cleared reaches containing more species, more germinable annual grasses and higher total numbers of germinable seeds. Soil seed bank composition was correlated with site openness suggesting that extant vegetation structure plays an important role in soil seed bank dynamics. Recruitment from the in situ soil seed bank will help restore only some components of the riparian plant community and may hinder restoration by introducing undesirable species. Copyright © 2008 John Wiley & Sons, Ltd.