bluuebunny/crossref_metadata_2025 huggingface dataset:
A new saturated/unsaturated model for stormwater infiltration systems
Authors: Browne Dale , Deletic Ana , Mudd Gavin M. , Fletcher Tim D.
Published: September 2008

Infiltration systems are widely used as an effective urban stormwater control measure. Most design methods and models roughly approximate the complex physical flow processes in these systems using empirical equations and fixed infiltration rates to calculate emptying times from full. Sophisticated variably saturated flow models are available, but rarely applied owing to their complexity. This paper describes the development and testing of an integrated one‐dimensional model of flow through the porous storage of a typical infiltration system and surrounding soils. The model accounts for the depth in the storage, surrounding soil moisture conditions and the interaction between the storage and surrounding soil. It is a front‐tracking model that innovatively combines a soil‐moisture‐based solution of Richard's equation for unsaturated flow with piston flow through a saturated zone as well as a reservoir equation for flow through a porous storage. This allows the use of a simple non‐iterative numerical solution that can handle ponded infiltration into dry soils. The model is more rigorous than approximate stormwater infiltration system models and could therefore be valuable in everyday practice. A range of test cases commonly used to test soil water flow models for infiltration in unsaturated conditions, drainage from saturation and infiltration under ponded conditions were used to test the model along with an experiment with variable depth in a porous storage over saturated conditions. Results show that the model produces a good fit to the observed data, analytical solutions and Hydrus. Copyright © 2008 John Wiley & Sons, Ltd.
A kinetic approach for simulating redox‐controlled fringe and core biodegradation processes in groundwater: model development and application to a landfill site in Piedmont, Italy
Authors: Rolle Massimo , Clement T. Prabhakar , Sethi Rajandrea , Di Molfetta Antonio
Published: September 2008

A three‐dimensional model for predicting redox controlled, multi‐species reactive transport processes in groundwater systems is presented. The model equations were fully integrated within a MODFLOW‐family reactive transport code, RT3D. The model can simulate organic compound biodegradation coupled to different terminal electron acceptor processes. A computational approach, which uses the spatial and temporal distribution of the rates of different redox reactions, is proposed to map redox zones. The method allows one to quantify and visualize the biological degradation reactions occurring in three distinct patterns involving fringe, pseudo‐core and core processes. The capabilities of the numerical model are demonstrated using two hypothetical examples: a batch problem and a simplified two‐dimensional reactive transport problem. The model is then applied to an unconfined aquifer underlying a leaking landfill located near the city of Turin, in Piedmont (Italy). At this site, high organic load from the landfill leachate activates different biogeochemical processes, including aerobic degradation, denitrification, manganese reduction, iron reduction, sulfate reduction and methanogenesis. The model was able to describe and quantify these complex biogeochemical processes. The proposed model offers a rational framework for simulating coupled reactive transport processes occurring beneath a landfill site. Copyright © 2008 John Wiley & Sons, Ltd.
Identifying individual rain events from pluviograph records: a review with analysis of data from an Australian dryland site
Authors: Dunkerley David
Published: September 2008

Rainfall is routinely reported as falling in ‘events’ or ‘storms’ whose beginning and end are defined by rainless intervals of a nominated duration (minimum inter‐event time, MIT). Rain events commonly exhibit fluctuations in rain rate as well as periods when rain ceases altogether. Event characteristics such as depth, mean rain rate, and the surface runoff volume generated, are defined in relation to the length of the rain event. These derived properties are dependent upon the value of MIT adopted to define the event, and the literature reveals a wide range of MIT criteria. Surprisingly little attention has been paid to this dependency, which limits the inter‐comparison of results in published work. The diversity in criteria also diminishes the usefulness of historical data on event durations, rain rates, etc., in attempts to document changes in the rainfall climate. This paper reviews the range of approaches used in the recognition of rain events, and a 5 year pluviograph record from an arid location is analysed. Changing MIT from 15 min to 24 h (lying within the range of published criteria) alters the number of rain events from 550 to 118. The mean rain rate declines from 2·04 mm h−1 to 0·94 mm h−1, and the geometric mean event duration rises from 0·66 h to 3·98 h. This wide variation in the properties of rain events indicates that more attention needs to be paid to the selection and reporting of event criteria in studies that adopt event‐based data analysis. The selection of a MIT criterion is shown to involve a compromise between the independence of widely‐spaced events and their increasingly variable intra‐event characteristics. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluating infiltration losses in a Mediterranean wetland: Las Tablas de Daimiel National Park, Spain
Authors: Castaño‐Castaño S. , Martínez‐Santos P. , Martínez‐Alfaro P. E.
Published: September 2008

Las Tablas de Daimiel National Park is a series of wetlands which naturally originated from groundwater discharges from the Mancha Occidental aquifer, Spain. Despite the relatively large size of this aquifer, 30 years of intensive groundwater pumping have significantly depleted the water table. As a result, wetlands only remain functional due to artificial inflows. Infiltration loss is therefore a key parameter to evaluate how much water is needed to maintain ecosystem functionality. Although yearly infiltration estimates existed prior to this work, these did not take into account key parameters such as the temporal evolution of the flooded area. This paper presents a more concrete estimate of the average infiltration losses. Infiltration is calculated as the closure term of daily water balances during a period of time where all other elements were known to an acceptable accuracy. A validation mechanism is provided to check the potential utility of the calculated infiltration in wetland management practices. Copyright © 2008 John Wiley & Sons, Ltd.
Daily pan evaporation modelling using multi‐layer perceptrons and radial basis neural networks
Authors: Kişi Özgür
Published: September 2008

This paper reports on investigations of the abilities of three different artificial neural network (ANN) techniques, multi‐layer perceptrons (MLP), radial basis neural networks (RBNN) and generalized regression neural networks (GRNN) to estimate daily pan evaporation. Different MLP models comprising various combinations of daily climatic variables, that is, air temperature, solar radiation, wind speed, pressure and humidity were developed to evaluate the effect of each of these variables on pan evaporation. The MLP estimates are compared with those of the RBNN and GRNN techniques. The Stephens‐Stewart (SS) method is also considered for the comparison. The performances of the models are evaluated using root mean square errors (RMSE), mean absolute error (MAE) and determination coefficient (R2) statistics. Based on the comparisons, it was found that the MLP and RBNN computing techniques could be employed successfully to model the evaporation process using the available climatic data. The GRNN was found to perform better than the SS method. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of artificial neural network models for hydrologic predictions at multiple gauging stations in an agricultural watershed
Authors: Mutlu E. , Chaubey I. , Hexmoor H. , Bajwa S. G.
Published: September 2008

This paper reports on an evaluation of the use of artificial neural network (ANN) models to forecast daily flows at multiple gauging stations in Eucha Watershed, an agricultural watershed located in north‐west Arkansas and north‐east Oklahoma. Two different neural network models, the multilayer perceptron (MLP) and the radial basis neural network (RBFNN), were developed and their abilities to predict stream flow at four gauging stations were compared. Different scenarios using various combinations of data sets such as rainfall and stream flow at various lags were developed and compared for their ability to make flow predictions at four gauging stations. The input vector selection for both models involved quantification of the statistical properties such as cross‐, auto‐ and partial autocorrelation of the data series that best represented the hydrologic response of the watershed. Measured data with 739 patterns of input–output vector were divided into two sets: 492 patterns for training, and the remaining 247 patterns for testing. The best performance based on the RMSE, R2 and CE was achieved by the MLP model with current and antecedent precipitation and antecedent flow as model inputs. The MLP model testing resulted in R2 values of 0·86, 0·86, 0·81, and 0·79 at the four gauging stations. Similarly, the testing R2 values for the RBFNN model were 0·60, 0·57, 0·58, and 0·56 for the four gauging stations. Both models performed satisfactorily for flow predictions at multiple gauging stations, however, the MLP model outperformed the RBFNN model. The training time was in the range 1–2 min for MLP, and 5–10 s for RBFNN on a Pentium IV processor running at 2·8 GHz with 1 MB of RAM. The difference in model training time occurred because of the clustering methods used in the RBFNN model. The RBFNN uses a fuzzy min‐max network to perform the clustering to construct the neural network which takes considerably less time than the MLP model. Results show that ANN models are useful tools for forecasting the hydrologic response at multiple points of interest in agricultural watersheds. Copyright © 2008 John Wiley & Sons, Ltd.
Protective effect of Juzen‐taiho‐to on hepatocarcinogenesis is mediated through the inhibition of Kupffer cell‐induced oxidative stress
Authors: Tsuchiya Masato , Kono Hiroshi , Matsuda Masanori , Fujii Hideki , Rusyn Ivan
Published: September 2008

Traditional herbal formulations, such as Juzen‐taiho‐to (TJ‐48), are used extensively in medical practice in Asia even though their mechanism of action remains elusive. This study tested a hypothesis that TJ‐48 is protective against hepatocarcinogenesis by impeding Kupffer cell‐induced oxidative stress. Forty‐eight patients were randomly assigned to receive TJ‐48 (n = 10), or no supplementation (n = 38) for up to 6 years after surgical treatment for hepatocellular carcinoma (HCC). In addition, to investigate the mechanism of protective action of TJ‐48, diethylnitrosamine‐containing water was administered for 22 weeks to male mice that were fed regular chow or TJ‐48‐containing diet. Liver tumor incidence, cell proliferation, number of 8‐hydroxy‐2′‐deoxyguanosine‐ or F4/80‐positive cells, and cytokine expression were evaluated. Although most of the patients experienced recurrence of HCC, a significantly longer intrahepatic recurrence‐free survival was observed in the TJ‐48 group. In mice, TJ‐48 inhibited the development of liver tumors, reduced oxidative DNA damage, inflammatory cell infiltration and cytokine expression. Administration of TJ‐48 improves intrahepatic recurrence‐free survival after surgical treatment of hepatocellular carcinoma. On the basis of animal experiments, we reason that the protective mechanism of TJ‐48 involves inhibition of Kupffer cells. This leads to lower levels of pro‐inflammatory cytokines and oxidants in liver which may slow down the process of hepatocarcinogenesis and improves hepatic recurrence‐free survival in patients with HCC. © 2008 Wiley‐Liss, Inc.
15‐Lipoxygenase‐1 activates tumor suppressor p53 independent of enzymatic activity
Authors: Zhu Hong , Glasgow Wayne , George Margaret D. , Chrysovergis Kali , Olden Kenneth , Roberts John D. , Eling Thomas
Published: September 2008

15‐LOX‐1 and its metabolites are involved in colorectal cancer. Recently, we reported that 15‐LOX‐1 overexpression in HCT‐116 human colorectal cancer cells inhibited cell growth by induction of p53 phosphorylation (4). To determine whether the 15‐LOX‐1 protein or its metabolites are responsible for phosphorylation of p53 in HCT‐116 cells, we used HCT‐116 cells that expressed a mutant 15‐LOX‐1. The mutant 15‐LOX‐1 enzyme, with a substitution of Leu at residue His361, was devoid of enzymatic activity. HCT‐116 cells transiently transfected with either native or mutant 15‐LOX‐1 showed an increase in p53 phosphorylation and an increase in the expression of downstream genes. Thus, 15‐LOX‐1 induces p53 phosphorylation independent of enzymatic activity. Treatment of A549 human lung carcinoma cells with IL‐4 increased the expression of 15‐LOX‐1 and also increased the expression of downstream targets of p53. This confirmed that the activation of p53 was also observed in wild‐type cells expressing physiological 15‐LOX‐1. Immunoprecipitation experiments revealed that 15‐LOX‐1 interacts with, and binds to, DNA‐dependent protein kinase (DNA‐PK). The binding of 15‐LOX‐1 to DNA‐PK caused an approximate 3.0‐fold enhancement in kinase activity, resulting in increased p53 phosphorylation at Ser15. Knockdown of DNA‐PK by small interfering RNA (siRNA) significantly reduced p53 phosphorylation. Furthermore, confocal microscopy demonstrated a colocalization of 15‐LOX and DNA‐PK in the cells. We propose that the 15‐LOX‐1 protein binds to DNA‐PK, increasing its kinase activity and results in downstream activation of the tumor suppressor p53, thus revealing a new mechanism by which lipoxygenases (LOX) may influence the phenotype of tumor cells. Published 2008 Wiley‐Liss, Inc.
Novel breast cancer risk alleles and endometrial cancer risk
Authors: McGrath Monica , Lee I‐Min , Buring Julie , Hunter David J. , De Vivo Immaculata
Published: September 2008

Genome‐wide association studies have identified several novel risk alleles for breast cancer. We hypothesized that genetic variants that are associated with breast cancer, a hormone‐related disease, would also be associated with endometrial cancer, another hormone‐related disease. We conducted a case–control study nested within the Nurses' Health Study and the Women's Health Study to investigate the associations between these 7 newly identified risk alleles for breast cancer and endometrial cancer risk using 692 invasive endometrial cancer cases and 1,723 matched controls. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) to assess the risk of endometrial cancer. In contrast to the breast cancer findings, we did not observe an increased risk of endometrial cancer. We observed an inverse association among rs2981582 (FGFR2) variant carriers [OR= 0.75 (95% CI: 0.60–0.95)]. We also observed a nonsignificant inverse association with rs889312 (MAP3K1) variant carriers [OR = 0.85 (95% CI: 0.68–1.05)] and rs1219648 (FGFR2) variant carriers [OR= 0.86 (95% CI: 0.69–1.06) and endometrial cancer risk. We did not observe associations with the other single nucleotide polymorphisms (SNPs) and endometrial cancer risk. Replication studies investigating these polymorphisms and endometrial cancer risk are warranted. However, our findings do suggest the potential importance of biological differences between endometrial and breast cancer with respect to the genes identified in the scans. The molecular mechanisms underlying these differences remain to be defined. © 2008 Wiley‐Liss, Inc.
Urban and industrial water use in the Krishna Basin, India
Authors: Van Rooijen Daniel J. , Turral Hugh , Biggs Trent Wade
Published: September 2008

Regional urbanization and industrial development require water that may put additional pressure on available water resources and threaten water quality in developing countries. In this study we use a combination of census statistics, case studies, and a simple model of demand growth to assess current and future urban and industrial water demand in the Krishna Basin in southern India. Water use in this “closed” basin is dominated by irrigation (61.9 billion cubic metres (BCM) yr−1) compared to a modest domestic and industrial water use (1.6 and 3.2 BCM yr−1). Total water diversion for non‐irrigation purposes is estimated at 7–8% of available surface water in the basin in an average year. Thermal power plants use the majority of water used by industries (86% or 2.7 BCM yr−1), though only 6.8% of this is consumed via evaporation. Simple modelling of urban and industrial growth suggests that non‐agricultural water demand will range from 10 to 20 BCM by 2030. This is 14–28% of basin water available surface water for an average year and 17–34% for a year with 75% dependable flow. Although water use in the Krishna Basin will continue to be dominated by agriculture, water stress, and the fraction of water supplies at risk of becoming polluted by urban and industrial activity, will become more severe in urbanized regions in dry years. Copyright © 2008 John Wiley & Sons, Ltd.
Efficient free energy calculations on small molecule host‐guest systems—A combined linear interaction energy/one‐step perturbation approach
Authors: Oostenbrink Chris
Published: September 2008

Two efficient methods to calculate binding affinities of ligands with proteins have been critically evaluated by using sixteen small ligand host‐guest complexes. It is shown that both the one‐step (OS) perturbation method and the linear interaction energy (LIE) method have complementing strengths and weaknesses and can be optimally combined in a new manner. The OS method has a sound theoretical basis to address the free energy of cavity formation, whereas the LIE approach is more versatile and efficient to calculate the free energy of adding charges to such cavities. The off‐term, which is neglected in the original LIE equation, can be calculated without additional costs from the OS, offering a powerful synergy between the two methods. The LIE/OS approach presented here combines the best of two worlds and for the model systems studied here, is more accurate than and as efficient as the original methods. It has a sound theoretical background and no longer requires any empirical parameters. The method appears very well suited for application in lead‐optimization programmes in drug research, where the structure and dynamics of a series of molecules is of interest, together with an accurate calculation of the binding free energy. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Can the hybrid meta GGA and DFT‐D methods describe the stacking interactions in conjugated polymers?
Authors: Dkhissi Ahmed , Ducéré Jean Marie , Blossey Ralf , Pouchan Claude
Published: September 2008

Newly developed hybrid meta density functionals and density functionals augmented by a classical London dispersion term have been systematically applied for the description of stacking energy and intermolecular distance of thiophene dimer and substituted thiophene dimer. The performance of the various approaches is compared with the benchmark ab‐initio calculations done with CCSD(T) (Tsuzuki et al., JACS 2002, 124, 12200). Our results indicate that, contrary to the previous DFT methods which are not reliable, the new generation of DFT performs better the stacking interactions. These functionals, and especially those with an empirical correction, are suitable for general application in conducting polymers and, in particular, the modeling of solid state in which the overlap of Π‐Π interactions between the conjugated chains is important. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Ultrastructural study of the intracellular behavior of four mineral elements in the lactating mammary gland cells: Study using conventional transmission electron microscopy
Authors: Ahlem Ayadi , Samira Maghraoui , Ali El Hili , Pierre Galle , Leila Tekaya
Published: September 2008

The effects of parenteral injection of aluminum, indium, gadolinium, or terbium in rats have been previously studied in several organs such as the liver, the kidneys, etc., but never in mammary glands. In this work, we have attempted to study the subcellular localization of these elements after their intraperitoneal administration. Their subsequent effects in the lactating mammary gland cells have also been studied. Our results using conventional transmission electron microscopy have shown that the lysosomes of the mammary glandular epithelial cells are the intracellular site of accumulation of the studied elements. Our results have also show intracellular deteriorations such as an expanded ergastoplasm and altered mitochondria after intraperitoneal injection of aluminum and indium. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
Novel lambda FRET spectral confocal microscopy imaging method
Authors: Megías Diego , Marrero Raquel , del Peso Borja Martínez , García María Ángel , Bravo‐Cordero José‐Javier , García‐Grande Aranzazu , Santos Andrés , Montoya María C.
Published: September 2008

We report a highly specific, sensitive, and robust method for analyzing fluorescence resonance energy transfer (FRET) based on spectral laser scanning confocal microscopy imaging. The lambda FRET (λFRET) algorithm comprises imaging of a FRET sample at multiple emission wavelengths rendering a FRET spectrum, which is separated into its donor and acceptor components to obtain a pixel‐based calculation of FRET efficiency. The method uses a novel off‐line precalibration procedure for spectral bleed‐through correction based on the acquisition of reference reflection images, which simplifies the method and reduces variability. λFRET method was validated using structurally characterized FRET standards with variable linker lengths and stoichiometries designed for this purpose. λFRET performed better than other well‐established methods, such as acceptor photobleaching and sensitized emission‐based methods, in terms of specificity, reproducibility, and sensitivity to distance variations. Moreover, λFRET analysis was unaffected by high fluorochrome spectral overlap and cellular autofluorescence. The λFRET method demonstrated outstanding performance in intra‐ and intermolecular FRET analysis in both fixed and live cell imaging studies. Microsc. Res. Tech., 2009. © 2008 Wiley‐Liss, Inc.
PCA‐based method for 3D shape recovery of microscopic objects from image focus using discrete cosine transform
Authors: Mahmood Muhammad Tariq , Choi Wook‐Jin , Choi Tae‐Sun
Published: September 2008

This article introduces a new algorithm for shape from focus (SFF) based on discrete cosine transform (DCT) and principal component analysis (PCA). DCT is applied on a small 3D neighborhood for each pixel in the image volume. Instead of summing all focus values in a window, AC parts of DCT are collected and then PCA is applied to transform this data into eigenspace. The first feature, containing maximum variation is employed to compute the depth. DCT and PCA are computationally intensive; however, the reduced data elements and algorithm iterations have made the new approach competitive and efficient. The performance of the proposed approach is compared with other methods by conducting experiments using image sequences of a synthetic and two microscopic objects. The evaluation is gauged on the basis of unimodality, monotonicity, and resolution of the focus curve. Two other global statistical metrics, root mean square error (RMSE) and correlation have also been applied for synthetic image sequence. Besides, noise sensitivity and computational complexity are also compared with other algorithms. Experimental results demonstrate the effectiveness and the robustness of the new method. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
Phosphoglycerate kinase 1 expression responds to freezing, anoxia, and dehydration stresses in the freeze tolerant wood frog, Rana sylvatica
Authors: Wu Shaobo , Storey Janet M. , Storey Kenneth B.
Published: September 2008

Natural freezing survival by wood frogs (Rana sylvatica) involves multiple organ‐specific changes in gene expression. Screening of a cDNA library made from brain of frozen frogs revealed freeze‐responsive up‐regulation of the glycolytic enzyme, phosphoglycerate kinase 1 (PGK1). Northern blots showed an approximately two‐fold increase in pgk1 transcripts in brain of frozen frogs whereas PGK1 protein levels rose by three‐ to five‐fold within 4–8 hr of freezing. Freezing also elevated pgk1 transcripts in liver but not in skin. Both transcript and protein levels also rose in response to two of the component stresses of freezing (anoxia and dehydration) with a particularly pronounced (11‐fold) increase in PGK1 protein in brain in response to anoxia. Amino acid sequence analysis showed 92.5% identity between wood frog and Xenopus laevis PGK1 and 86–88% identity with the zebrafish, chicken, and human protein. Four unique amino acid substitutions in the wood frog protein could be important in maintaining the functional conformation of the wood frog protein at low body temperatures. Elevated amounts of PGK1, one of the ATP‐generating reactions of glycolysis, in wood frog brain during freezing would enhance the glycolytic capacity of the organ and support the maintenance of cellular energetics under the ischemic conditions of the frozen state. J. Exp. Zool. 311A:57–67, 2009. © 2008 Wiley‐Liss, Inc.
Salinity stress results in rapid cell cycle changes of tilapia (Oreochromis mossambicus) gill epithelial cells
Authors: Kammerer Brittany D. , Sardella Brian A. , Kültz Dietmar
Published: September 2008

We have developed a technique for immunocytochemistry of fish gill cells that we used to quantify tilapia (Oreochromis mossambicus) mitochondria‐rich cells (MRC) and other gill cells (non‐MRC) within different cell cycle phases by laser scanning cytometry. Gill cells fixed on coverslips were triple stained with propidium iodide to distinguish G1 vs. G2 phases, Ser10‐phosphorylated histone H3 antibody to label mitotic cells, and Na+/K+ ATPase antibody to label MRC. These parameters were measured at 0 (control), 4, 8, 16, 24, 48, 72, and 168 hr (1 week) following exposure of freshwater (FW) acclimated fish to 2/3 seawater (SW). MRC increased mitotic activity very rapidly peaking at 8 hr following SW exposure. This change in mitotic MRC is indicative of epithelial reorganization during SW acclimation. In contrast to MRC, the proportion of non‐MRC (likely pavement cells (PVC)) in mitosis did not change significantly in response to SW exposure. Moreover, twice as many MRC were in mitosis compared with non‐MRC, suggesting that MRC turn over faster than other cell types during SW acclimation. Following the mitosis peak, MRC accumulated in G2 phase over a period of 16–72 hr post‐SW exposure. We also observed G2 arrest with similar kinetics following SW exposure in tilapia non‐MRC (likely PVC). We interpret the G2 arrest that occurs after an initial wave of transient increase in MRC mitosis as a means for conserving energy for dealing with the osmotic stress imposed during the exposure of FW fish to SW. J. Exp. Zool. 311A:80–90, 2009. © 2008 Wiley‐Liss, Inc.
Hydrophilic interaction chromatography in nonaqueous elution mode for separation of hydrophilic analytes on silica‐based packings with noncharged polar bondings*
Authors: Bicker Wolfgang , Wu JunYan , Lämmerhofer Michael , Lindner Wolfgang
Published: September 2008

Chromatographic effects of dedicated stationary and mobile phase variations in hydrophilic interaction chromatography (HILIC) were investigated using a set of nucleobases, nucleosides and deoxynucleosides as polar test solutes. Retention and selectivity profiles were comparatively mapped on four in‐house developed silica materials modified with short alkyl chains (C4, C5) which carry hydroxyl functionalities (including diol motifs) as well as embedded sulphide or sulphoxide groups. These data were complemented by results obtained with two commercially available diol‐type phases and a bare silica column. Besides elucidation of packing‐related aspects this work concentrated specifically on extending aqueous HILIC (AQ‐HILIC) to nonaqueous polar‐organic elution conditions herein termed NA‐HILIC. The exchange of the polar modifier water by various alcohols in ACN‐rich mobile phases containing 5 mM ammonium acetate decreased the eluotropic strength of the resulting eluents. The gain in retention largely followed the order ethanol (EtOH) > methanol (MeOH) > 1,2‐ethanediol (Et(OH)2) and was accompanied by distinct effects on chromatographic selectivity. For example, on the most polar home‐made packing the purine nucleoside selectivity guanosine/adenosine increased from 2.25 in the AQ‐HILIC (kguanosine = 8.3) to 7.33 (kguanosine = 59) in the NA‐HILIC mode when EtOH was employed as NA modifier while this value was 5.84 and 2.93 with MeOH and Et(OH)2, respectively (eluent: 5 mM ammonium acetate in ACN/modifier 90:10 v/v). Besides the type of protic modifier its percentage as well the retention and selectivity effects upon varying the ammonium acetate concentration and column temperature, respectively, were also investigated. Notable inter‐column differences were found for all of these elution parameters. A mixed‐mode retention model composed of partitioning and adsorption is proposed for both AQ‐ and NA‐HILIC retention processes. The potential of (i) the implementation of novel polar bondings (such as ones containing sulphoxide functionalities) and (ii) the comprehensive exploitation of elution variables (type of protic modifiers, salt, etc.) for providing new selectivity increments to the separation of polar analytes in HILIC is emphasised.
Determination of uranium, iron, copper, and nickel in rock and water samples by MEKC
Authors: Mirza Muhammad Aslam , Khuhawar Muhammad Yar , Arain Rafee
Published: September 2008

A micellar electrokinetic capillary chromatographic (MEKC) procedure has been developed for the separation and determination of dioxouranium (VI), iron(III), copper(II), and nickel(II) using bis(salicylaldehyde)propylenediimine (H2SA2Pn) as chelating reagent with a total run time of <3 min. Sodium dodecyl sulphate (SDS) was used as micellar medium at pH 8.1 with sodium tetraborate buffer (0.1 M). Uncoated fused silica capillary with effective length 38.8 cm×75 μm id was used with an applied voltage of 30 kV and photo‐diode array detection at 228 nm. Linear calibrations were established within 0.045–1000 μg/mL of each element with detection limit within 15–122 ng/mL. The method was applied to the analysis of spring water and rock samples. The presence of uranium in rock and spring water samples was established within 1.58–1739.3 μg/g and 0.047–0.712 μg/mL with relative standard deviation within 0.9–2.1% and 1.3–2.6% respectively. Uranium ore and water samples were also assayed by the standard addition technique. Recovery of uranium was >98% with RSD up to 2.7%. Copper, nickel, and iron in their combined matrix were concurrently determined within RSD 0.6–3.6% (n = 5) and the results obtained were compared with those of flame AAS.
Chiral analysis of milnacipran by a nonchiral HPLC – circular dichroism: Improvement of the linearity of dichroic response by temperature control
Authors: Lecoeur‐Lorin Marie , Delépée Raphaël , Ribet Jean‐Paul , Morin Philippe
Published: September 2008

The determination of the enantiomeric excess (e.e.) of a basic drug has been investigated in LC using a nonchiral stationary phase and a circular dichroism (CD) detector in order to avoid expensive chiral columns. The CD detector records both dichroic (Δε) and UV (ε) signals at the same wavelength and calculates the anisotropy factor (g = Δε/ε), which is linearly related to the e.e. The enantiomeric and chemical composition of a chiral drug can be simultaneously determined on a nonchiral HPLC support. However, the g factor from the CD signal is temperature dependent. Indeed, the temperature has an influence on the stability of the CD signal and the linear regression between g factor and the e.e. of 1R,2S‐enantiomer. So, a decrease in temperature gives rise to an improvement of the above‐mentioned linearity correlation. After optimization of chromatographic parameters (porous graphitic carbon‐based column, methanol/ phosphate buffer as mobile phase) and selection of CD wavelength, a linear regression of g factor versus e.e. of 1R,2S‐enantiomer was obtained at temperature‐controlled CD detection and an LOQ of 94% was found. The enantiomeric composition of milnacipran was determined with good accuracy.
Effect of large volume injection of hydrophobic solvents on the retention of less hydrophobic pharmaceutical solutes in RP‐LC
Authors: Udrescu Stefan , Medvedovici Andrei , David Victor
Published: September 2008

Injection of large volumes of samples in solvents other than mobile phase composition has been proved for some less hydrophobic compounds. Thus, the retention behavior of several compounds of pharmaceutical interest (isosorbide‐2‐nitrate, isosorbide‐5‐nitrate, tropicamide, pentoxifylline, and methyl p‐hydroxybenzoate) was studied by using different hydrophobic solvents (n‐hexane, n‐heptane, or i‐octane) as sample solvents. Two types of stationary phases were used: octyl and octadecyl modified silica (both of Zorbax Eclipse type). The experiments showed a linear dependence between capacity factor of each solute and sample injection volume, up to maximum volume values of about 680 μL for C8 stationary phase and 580 μL for C18 stationary phase, when the solutes are no longer retained in stationary phase. Injection of large volumes of these hydrophobic solvents is thus possible in RP‐LC with a gradual reduction of retention and peak efficiency. Two major conditions are however necessary in order to apply such an injection approach: the solutes must have a proper solubility in hydrophobic solvents and meanwhile they have to be less hydrophobic than the sample solvent in order to avoid competition with solvent molecules in partitioning between mobile and stationary phases.
Combined effect of temperature and organic modifier concentration on the retention under single mode gradient conditions in reversed‐phase HPLC
Authors: Pappa‐Louisi Adriani , Nikitas Panos , Zisi Christiana , Papachristos Kostas
Published: September 2008

The combined effect of temperature, T, and organic modifier concentration, φ, on the retention under gradient conditions in RPLC is studied by considering, both theoretically and experimentally gradients, of φ at constant T and gradients of T at constant φ. Two approaches are examined: in the first approach the prediction of the elution time of a sample solute is based on the isocratic/isothermal properties of this solute. The second approach is based on a direct fitting procedure of a proper retention model to 2‐D isocratic/T‐gradient or isothermal/φ‐gradient retention data. These approaches were tested using alkylbenzes in eluting systems modified by ACN. We found that both approaches can give excellent predictions under certain prerequisites. However, the first approach exhibits the notable advantage that it can be used effectively to predict retention times under any kind of φ‐gradients at constant T or T‐gradients at constant φ. The second approach has the advantage that it is relatively simple but its applicability is very restricted since its predictions are satisfactory only if the gradients are of the same kind with those used in the fitting procedure and the conditions lie within those used for fitting.
Determination of carbohydrate‐deficient transferrin in human serum by two capillary zone electrophoresis methods and a direct immunoassay: Comparison of patient data
Authors: Marti Ulrich , Joneli Jeannine , Caslavska Jitka , Thormann Wolfgang
Published: September 2008

Data obtained with two CZE assays for determining carbohydrate‐deficient transferrin (CDT) in human serum under routine conditions, the CAPILLARYS CDT and the high‐resolution CEofix (HR‐CEofix) CDT methods, are in agreement with patient sera that do not exhibit interferences, high trisialo‐transferrin (Tf) levels or genetic variants. HR‐CEofix CDT levels are somewhat higher compared to those obtained with the CAPILLARYS method and this bias corresponds to the difference of the upper reference values of the two assays. The lower resolution between disialo‐Tf and trisialo‐Tf observed in the CAPILLARYS system (mean: 1.24) compared to HR‐CEofix (mean: 1.74) is believed to be the key for this difference. For critical sera with high trisialo‐Tf levels, genetic variants, or certain interferences in the β‐region, the HR‐CEofix approach is demonstrated to perform better than CAPILLARYS. However, the determination of CDT with the HR‐CEofix method can also be hampered with interferences. Results with disialo‐Tf values larger than 3% in the absence of asialo‐Tf should be evaluated with immunosubtraction of Tf and possibly also confirmed with another CZE method or by HPLC. Furthermore, data gathered with the N Latex CDT direct immunonephelometric assay suggest that this assay can be used for screening purposes. To reduce the number of false negative results, CDT data above 2.0% should be confirmed using a separation method.
Determination of amino acid neurotransmitters in human cerebrospinal fluid and saliva by capillary electrophoresis with laser‐induced fluorescence detection
Authors: Deng Ying‐Hua , Wang Hong , Zhang Hua‐Shan
Published: September 2008

A CE–LIF detection method has been developed to identify and quantitate six amino acid neurotransmitters including glutamic acid, aspartic acid, γ‐aminobutyric acid, glycine, taurine, and glutamine. N‐Hydroxysuccinimidyl fluorescein‐O‐acetate, a fluorescein‐based dye, was employed for the derivatization of these neurotransmitters prior to CE–LIF analysis. Different parameters which influenced separation and derivatization were optimized in detail. Under optimum conditions, linearity was achieved within concentration ranges of up to three orders of magnitudes for those analytes with correlation coefficients from 0.9989 to 0.9998. The LODs ranged from 0.06 nM to 0.1 nM, and are thus superior or equivalent to those previously reported in the literature using CE–LIF detection. The proposed method has been successfully applied to the determination of amino acid neurotransmitters in biological samples such as human cerebrospinal fluid and saliva with satisfactory recoveries.
Recovering oil from corn ethanol fermentation by‐products
Authors: Wang Tong
Published: September 2008

Removing oil from by‐products of corn fermentation is desirable for improving feed quality and providing an alternative source of oil for biodiesel production. We are investigating ways to increase oil removal by centrifugation during the typical dry grind fermentation process. We have to first make oil or oil containing “bodies” go into the liquid phase and then free the oil so it can be separated by centrifugation. This report outlines our research approaches and results.
Amphiphilic Branched Polymers as Antimicrobial Agents
Authors: Pasquier Nicolas , Keul Helmut , Heine Elisabeth , Moeller Martin , Angelov Borislav , Linser Sebastian , Willumeit Regine
Published: September 2008

Cationic amphiphilic polymers were prepared from PEI and functional ethylene carbonates bearing cationic, hydrophobic or amphiphilic groups. The polymers are designed to exhibit antimicrobial properties. In a one‐step addition, different functional ethylene carbonates were added to react with the primary amine groups of PEI. The water soluble polymers were studied regarding their ability to form soluble aggregates. Their hydrodynamic radii, their inhibition potential against proliferation of E. coli and their hemolytic potential were determined. A structure‐property relationship was established by analyzing the antimicrobial activity as a function of the ratio of alkyl to cationic groups, length of the alkyl chains, and molecular weight of the PEI.

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Analysis of macrolide antibiotics, using liquid chromatography‐mass spectrometry, in food, biological and environmental matrices
Authors: Wang Jian
Published: September 2008

Macrolides are a group of antibiotics that have been widely used in human medical and veterinary practices. Analysis of macrolides and related compounds in food, biological, and environmental matrices continue to be the focus of scientists for the reasons of food safety, pharmacokinetic studies, and environmental concerns. This article presents an overview on the primary biological properties of macrolides and their associated analytical issues, including extraction, liquid chromatography‐mass spectrometry (LC‐MS), method validation, and measurement uncertainty. The main techniques that have been used to extract macrolides from various matrices are solid‐phase extraction and liquid–liquid extraction. Conventional liquid chromatography (LC) with C18 columns plays a dominant role for the determination of macrolides, whereas ultra‐performance liquid chromatography (UPLC) along with sub‐2 µm particle C18 columns reduces run time and improves sensitivity. Mass spectrometry (MS), serving as a universal detection technique, has replaced ultraviolet (UV), fluorometric, and electrochemical detection for multi‐macrolide analysis. The triple‐quadrupole (QqQ), quadrupole ion trap (QIT), triple‐quadrupole linear ion trap, time‐of‐flight (TOF), and quadrupole time‐of‐flight (QqTOF) mass spectrometers are current choices for the determination of macrolides, including quantification, confirmation, identification of their degradation products or metabolites, and structural elucidation. LC or UPLC coupled to a triple‐quadrupole mass spectrometer operated in the multiple‐reaction monitoring (MRM) mode (LC/MS/MS) is the first choice for quantification. UPLC‐TOF or UPLC‐QqTOF has been recognized as an emerging technique for accurate mass measurement and unequivocal identification of macrolides and their related compounds. © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Inc., Mass Spec Rev 28:50–92, 2009
Neuropathy as a potential complication of levodopa use in Parkinson's disease
Authors: Toth Cory , Brown Martin Sutton , Furtado Sarah , Suchowersky Oksana , Zochodne Douglas
Published: September 2008

The presence and potential etiologies of peripheral neuropathy (PN) in patients with Parkinson's Disease (PD) is unknown. We examined for presence of PN in patients with PD. From a PD patient population of 500 patients screened for features of symptomatic PN, patients were further selected for clinical, electrophysiological, and laboratory studies related to PN. This PD patient population with idiopathic PN (PD‐IPN) was compared to a group of PD patients without PN (PD‐only), and a large group of patients without PD with idiopathic PN (IPN) for abnormalities in Cbl, fasting homocysteine (Hcy), and fasting methylmalonic acid (MMA) levels. PD‐IPN and IPN patients identified with abnormalities in Cbl, Hcy, or MMA levels were treated with intramuscular Cbl for 1 to 2 years. Of 49 PD patients with symptomatic PN, 34 patients (69%) had PD‐IPN, and 32/34 (94%) had abnormal Hcy or MMA levels as compared to 26/258 (10%) of IPN patients. Cumulative lifetime L‐dopa dosage and fasting MMA levels were associated with PN severity. Cbl therapy led to improvements in Hcy and MMA levels in all groups, and PN in PD‐IPN patients stabilized during therapy. PN in PD patients may be associated with iatrogenic Cbl metabolic abnormalities. Alternatively PN may be a peripheral nervous system manifestation of PD. © 2008 Movement Disorder Society
The use of smell identification tests in the diagnosis of Parkinson's disease in Brazil
Authors: Silveira‐Moriyama Laura , Carvalho Margarete de Jesus , Katzenschlager Regina , Petrie Aviva , Ranvaud Ronald , Barbosa Egberto Reis , Lees Andrew J.
Published: September 2008

Smell identification tests may be of routine clinical value in the differential diagnosis of PD but are subject to cultural variation and have not been systematically evaluated in the Brazilian population. We have applied culturally adapted translations of the University of Pennsylvania 40‐item smell identification test (UPSIT‐40) and the 16‐item identification test from Sniffin' Sticks (SS‐16) to nondemented Brazilian PD patients and controls. Pearson's correlation coefficient between the test scores was 0.76 (95% CI 0.70–0.81, n = 204, P < 0.001). To calculate reliability measures for each test we used the diagnosis (either PD or control) as outcome variable for separate logistic regression analyses using the score in the UPSIT‐40 or the SS‐16 as a covariate. The SS‐16 specificity was 89.0% with a sensitivity of 81.1% (106 PD and 118 controls). The UPSIT‐40 specificity was 83.5% and its sensitivity 82.1% (95 PD and 109 controls). Regression curves were used to associate an individual's smell test score with the probability of belonging to the PD, as opposed to the control group. Our data provide support for the use of the UPSIT‐40 and SS‐16 to help distinguish early PD from controls. © 2008 Movement Disorder Society
Chorea‐acanthocytosis: Report of two Brazilian cases
Authors: Rodrigues Guilherme Riccioppo , Walker Ruth H. , Bader Benedikt , Danek Adrian , Marques Wilson , Tumas Vitor
Published: September 2008

Chorea‐acanthocytosis (ChAc) is a neurodegenerative disorder characterized by chorea, neuropsychiatric disturbances and acanthocytosis, caused by mutations of VPS13A. This gene produces the protein chorein which is absent in patients with ChAc on Western blot assay. We report the first two Brazilian patients with ChAc confirmed by chorein detection. Patient 1 is a 36‐year‐old man with chorea, epilepsy, myopathy, and suicidal ideation. Patient 2 is a 60‐year‐old woman with a 30 year history of psychiatric disturbances, epilepsy, choreic movements, and myopathy. Both patients had acanthocytosis, elevated creatine kinase (CK), and absence of chorein on Western blot analysis. The presence of chorea and neuropsychiatric disturbances associated with elevated CK levels, epilepsy, hyporeflexia, and acanthocytosis suggests the diagnosis of ChAc. Chorein assay of peripheral blood confirms the diagnosis. © 2008 Movement Disorder Society
Traffic matrix estimation based on a square root Kalman filtering algorithm
Authors: Zhou Jingjing , Yang Jiahai , Yang Yang , Liu Hongbo , Zeng Ming
Published: September 2008

The traffic matrix (TM) is one of the crucial inputs for many network management and traffic engineering tasks. As it is usually impossible to directly measure traffic matrices, it becomes an important research topic to infer them by modeling incorporating measurable data and additional information. Many estimation methods have been proposed so far, but most of them are not sufficiently accurate or efficient. Researchers are therefore making efforts to seek better estimation methods. Of the proposed methods, the Kalman Filtering method is a very efficient and accurate method. However, the error covariance calculation components of Kalman filtering are difficult to implement in realistic network systems due to the existence of ill‐conditioning problems. In this paper, we proposed a square root Kalman filtering traffic matrix estimation (SRKFTME) algorithm based on matrix decomposition to improve the Kalman filtering method. The SRKFTME algorithm makes use of the evolution equations of forecast and analysis error covariance square roots. In this way the SRKFTME algorithm can ensure the positive definiteness of the error covariance matrices, which can solve some ill‐conditioning problems. Also, square root Kalman filtering will be less affected by numerical problems. Simulation and actual traffic testing results show superior accuracy and stability of SRKFTME algorithm compared with prior Kalman filtering methods. Copyright © 2008 John Wiley & Sons, Ltd.