bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic and environmental contributions to obesity and binge eating
Authors: Bulik Cynthia M. , Sullivan Patrick F. , Kendler Kenneth S.
Published: March 2003

Objective

Binge eating is present in a substantial proportion of obese individuals. A tendency toward obesity has been identified as a risk factor for eating disorders such as bulimia nervosa and binge eating disorder. The purpose of this article was to determine the extent of overlap between genetic and environmental factors that contribute to the liability to obesity and binge eating.

Research Method

In a population‐based sample of 2163 female twins, we conducted bivariate twin modeling to explore the relation between the genetic and environmental risk factors for obesity and binge eating.

Results

Bivariate twin modeling revealed substantial heritability for obesity (0.86: 95% CI, 0.77–0.94), moderate heritability for binge eating (0.49: 95% CI, 0.38–0.61), and a modest genetic correlation of +.34 (95% CI, 0.19–0.50) between the two traits.

Conclusions

Both binge eating and obesity are heritable conditions, and there seems to be only modest overlap in the genetic risk factors that increase liability to each condition. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 293–298, 2003.
A longitudinal examination of patterns in girls' weight concerns and body dissatisfaction from ages 5 to 9 years
Authors: Davison Kirsten Krahnstoever , Markey Charlotte N. , Birch Leann L.
Published: March 2003

Objective

To examine the development of girls' weight concerns and body dissatisfaction from ages 5 to 9 years and how change and continuity in these constructs from age 5 to 7 years is associated with girls' eating attitudes, dietary restraint, and dieting status at age 9.

Methods

Weight concerns, body dissatisfaction, and weight status were assessed for 182 girls when they were 5, 7, and 9 years old, and their eating attitudes, dietary restraint, and dieting status were assessed when they were 9.

Results

Girls tended to maintain their rank in weight concerns and body dissatisfaction across ages 5 to 9 years, and associations among girls' weight concerns, body dissatisfaction, and weight status increased with age. In addition, positive associations were found between changes in girls' weight concerns, body dissatisfaction, and weight status across ages 7 to 9. Finally, girls' who reported high weight concerns or high body dissatisfaction across ages 5 to 7 reported higher dietary restraint, more maladaptive eating attitudes, and a greater likelihood of dieting at age 9, independent of their weight status.

Conclusion

Girls' reported weight concerns and body dissatisfaction across middle childhood showed consistency over time, were systematically related to their weight status, and predicted their dietary restraint, eating attitudes, and the likelihood of dieting at age 9. These results reflect patterns identified among adolescent girls and women. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 320–332, 2003.
Severe neutropenia with gelatinous bone marrow transformation in anorexia nervosa: A case report
Authors: Nishio Shinichiro , Yamada Hiroshi , Yamada Kaoru , Okabe Hirofumi , Okuya Takafumi , Yonekawa Osamu , Ono Takaaki , Sahara Naohi , Tamashima Sadahiro , Ihara Michio
Published: March 2003

A 28‐year‐old woman with a history of anorexia nervosa was admitted with excessive weight loss, edema, and amenorrhea. She had lost 34% of her previous body weight within 2 years, and her body mass index was 12.3kg/m2. The leukocyte count on admission was 2150/μl and gradually decreased to 980/μl (neutrophils; 276/μl). Bone marrow biopsy disclosed gelatinous transformation with hypocellularity. After the patient was treated with intravenous nutritional support, the severe neutropenia improved to the level on admission. Hematological abnormalities seem to be common in anorexia nervosa, but severe neutropenia with gelatinous bone marrow transformation has rarely been reported. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 360–363, 2003.
Echocardiographic investigation of pericardial effusion in a case of anorexia nervosa
Authors: Inagaki Takuji , Yamamoto Masahiro , Tsubouchi Ken , Miyaoka Tsuyoshi , Uegaki Jun , Maeda Takahiro , Horiguchi Jun , Yamane Yuko , Kato Yuzuru
Published: March 2003

Objective

Pericardial effusion has recently been reported as a complication of anorexia nervosa. A distinct pathophysiological cause of it could not be revealed. In some reports, there was a probable correlation between weight gain and reduction of pericardial effusion in anorexia nervosa cases. We encountered a case in which pericardial effusion remitted completely along with body weight increase and normalization of low T3 syndrome. These findings suggest that the reduction of pericardial effusion may correlate with both weight gain and low T3 normalization. Plasma brain natriuretic peptide (BNP) levels were increased in this case despite heart failure, and plasma BNP decreased as pericardial effusion remitted. The measurement of serum BNP level may be a clinical parameter in such a case of pericardial effusion. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 364–366, 2003.
Neuroticism and low self‐esteem as risk factors for incident eating disorders in a prospective cohort study
Authors: Cervera Salvador , Lahortiga Francisca , Angel Martínez‐González Miguel , Gual Pilar , Irala‐Estévez Jokin de , Alonso Yolanda
Published: March 2003

Objective

To assess the role of neuroticism and low self‐esteem as risk factors for eating disorders (ED).

Method

A representative sample of girls 12–21 years old from Navarre, Spain. Girls free from any ED in 1997 were followed up for 18 months and reevaluated using DSM‐IV criteria. Multivariable logistic models were used to examine associations between neuroticism (Eysenck Inventory) or low self‐esteem (36‐item scale) and incident ED.

Results

Higher levels of neurotic personality increased the risk of ED (adjusted odds ratio [OR] for the highest quartile, 3.3; 95% Cl; 1.6–4.8). High levels of self‐esteem were protective (OR, 0.32; 95% CI, 0.16–0.66). Neuroticism was a more powerful predictor than low self‐esteem.

Discussion

Our results provide prospective evidence supporting the role of neuroticism and low self‐esteem as major determinants of ED. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 271–280, 2003.
Body image dissatisfaction and disordered eating in black and white women
Authors: Perez Marisol , Joiner Thomas E.
Published: March 2003

Objective

This study predicted and found that body image dissatisfaction and bulimic symptoms have a curvilinear relationship among undergraduate women.

Results

For the women in this sample, regardless of race, body image dissatisfaction correlated with bulimic symptoms, such that women who perceived themselves as bigger or smaller than the ideal body size for their ethnic group endorsed bulimic symptoms. Black and white women differed regarding their ethnic group's ideal body image and their self‐perceptions of how they compared with the ideal image. Black women tended to report being underweight, whereas white women tended to report being overweight.

Discussion

The findings in this study suggest that some black women are not buffered against eating disorders as suggested in previous research. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 342–350, 2003.
Cognitive impairment in anorexia nervosa is not due to depressed mood
Authors: McDowell Bradley D. , Moser David J. , Ferneyhough Karin , Bowers Wayne A. , Andersen Arnold E. , Paulsen Jane S.
Published: March 2003

Objective

Previous research has revealed cognitive deficits in patients with anorexia nervosa. It is unclear whether these deficits are linked to co‐morbid depression in this population. We examined the relationship between depressive symptoms and cognitive functioning.

Method

A large sample of subjects (N = 98) was examined using a common measure of cognitive ability and two measures of depression.

Results

We confirmed that there is no relationship between depression and cognitive ability in this group.

Discussion

This suggests that alternative explanations be explored for cognitive deficits in patients with anorexia nervosa. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 351–355, 2003.
Sonovoltammetric Elucidation of Electron Transfer Rates: The Oxidation of Dimethyl‐p‐phenylenediamine in Aqueous Solution
Authors: Banks Craig E. , Lawrence Nathan S. , Compton Richard G.
Published: March 2003

The electrochemical oxidation of dimethyl‐p‐phenylenediamine (DMPD) in aqueous solution (pH 7 phosphate buffer) has been studied under conventional hydrodynamic and microelectrode voltammetric conditions and found to undergo a two‐electron electrochemically reversible oxidation. Upon the application of ultrasound to the system an observed shoulder emerges in the oxidation wave. This effect has been attributed to the resolution of the two‐electron transfer processes occurring: the first a relatively fast electron transfer (0.1 cm s−1) followed by a second slower (10−3 cm s−1) electron transfer: under the very high mass transport rates induced by insonation an overpotential develops for the second electron transfer so leading to the observed voltammetric resolution. The range of mass transport conditions accessible via sonication allows the estimation of the two rate constants reported.
Electron Transfer Kinetics of Ferrocene at Microcrystalline Boron‐Doped Diamond Electrodes: Effect of Solvent and Electrolyte
Authors: Haymond Shannon , Babcock Gerald T. , Swain Greg M.
Published: March 2003

Cyclic voltammetric measurements were made using well‐characterized microcrystalline boron‐doped diamond thin‐film electrodes to test the material's responsiveness for ferrocene as a function of scan rate, solvent, and electrolyte composition. Apparent heterogeneous electron transfer rate constants, k°app, of 0.042±0.015, 0.048±0.015, and 0.008±0.002 cm/s were observed in 0.1 M NaClO4/CH3CN, 0.1 M TBAClO4/CH3CN, and 0.1M TBAClO4/CH2Cl2, respectively. These rate constants, obtained using electrodes without any type of pretreatment, are similar to those observed for freshly polished glassy carbon. The results demonstrate that boron‐doped diamond is a viable material for the electrochemical analysis of nonaqueous analytes.
Polypyrrole Bilayers: Charge Trapping and Application for Amperometric Ions Sensing
Authors: Malinowska Beata , Maksymiuk Krzysztof
Published: March 2003

Bilayers composed of polypyrrole: doped by perchlorate ions (PPy(ClO4) – anion exchanging inner layer) and by dodecyl sulfate ions (PPy(DS) – cation exchanging outer layer) are very effective charge trapping systems that are usually not observed for other bilayers comprised of polypyrrole. Chronopotentiometric experiments carried out for oxidation and reduction showed that the trapping effect in the inner layer resulted from different ion exchange properties of the component polymers, leading to a low permeability of the reduced outer layer towards anions. Estimated diffusion coefficients of Cl− anions in the oxidized and reduced PPy(DS) are in the range of 10−9 and lower than 10−10 cm2 s−1, respectively. The presence of the outer layer limiting the ion transfer was found to be beneficial to improve the signal resolution in amperometric mode of ion sensing within wide KCl concentration range, from 10−5 M up to 3 M. The influence of experimental conditions (film thickness, response time) on optimization of this novel kind of polymeric bilayer ion sensors was studied.
Square‐Wave Voltammetry of the Molybdenum‐1,10 Phenanthroline‐Fulvic Acids Complex: Redox Kinetics Measurements
Authors: Quentel François , Mirčeski Valentin , Laouenan André , Elleouet Catherine , Madec Christian Louis
Published: March 2003

The reduction process of molybdenum in the presence of fulvic acids and phenanthroline was investigated by square‐wave voltammetry (SWV). The mixed‐ligand complex of molybdenum exhibits a pronounced tendency to adsorb onto the mercury electrode surface. The electrode reaction proceeds as a surface process in which both components of the redox couple are firmly confined to the electrode surface. The kinetics of the electrode reaction is studied utilizing the properties of “split SW peaks” and “quasireversible maximum”. The kinetic parameters obtained with two different square‐wave voltammetric methods are in good agreement. In 0.5 mol/L NaCl solution with pH 2.5 the kinetic parameters are: standard rate constant ks=8±2 s−1, cathodic electron transfer coefficient α=0.41±0.05, and number of exchanged electrons n=2. The SW kinetic measurements are confirmed by cyclic voltammetric method.
Homooxacalix[3]arene Derivatives as Ionophores for Serotonin‐Selective Membrane Electrodes
Authors: Katsu Takashi , Ido Kazuyuki , Sagara Sachie , Tsubaki Kazunori , Fuji Kaoru
Published: March 2003

Homooxacalix[3]arene derivatives are effective ionophores for constructing serotonin‐selective membrane electrodes. An electrode based on one of the derivatives, tris(methoxyphenylpropyloxy)hexahomooxacalix[3]arene‐triethyl ether, with potassium tetrakis(p‐chlorophenyl)borate (20 mol% relative to the ionophore) as an ionic additive and bis(2‐ethylhexyl) sebacate as a solvent mediator in a poly(vinyl chloride) membrane matrix, displayed much better selectivity for serotonin than for various organic ammonium ions and inorganic cations. The electrode exhibited a near‐Nernstian response to serotonin in the concentration range of 2×10−4 to 1×10−2 M with a slope of 56.4 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM Na2HPO4/NaH2PO4 (pH 7.4). The limit of the detection was 8×10−5 M. The selectivity pattern of this electrode was quite different from that of an electrode using calix[6]arene‐hexaacetic acid hexaethyl ester, a well‐known ionophore for primary organic ammonium ions, which did not induce an enhanced response to serotonin. The developed electrode was used for the active loading of serotonin in liposomes induced by transmembrane pH gradients.
Recognition of Monohydrogen Anions of Geometrical and Positional Isomers of Dicarboxylic Acids Based on Polymeric Liquid Membranes Incorporating Polyamine Host
Authors: Szymanska Iwona , Radecka Hanna , Radecki Jerzy , Pietraszkiewicz Marek , Pietraszkiewicz Oksana
Published: March 2003

Macrocyclic lipophilic polyamines were applied as the sensory elements of polymeric liquid membrane electrodes. These hosts gain the anion receptor functionality upon protons uptake from the aqueous solutions. The electrodes studied were able to distinguish potentiometricaly isomers of monocharged and doublecharged forms of ethylene and benzene dicarboxylic acids. The selectivity of interaction between protonated hosts and anionic guests relays not only on the electrostatic interactions, but on hydrogen bounds formations as well. The influence of lipophilicity of protonated hosts on the potential response generation was discussed.
Polarographic Detection of Arenediazonium Ions. Optimization of the Method and Application for Investigating Dediazoniation Mechanisms
Authors: Bravo‐Díaz Carlos , González‐Romero Elisa
Published: March 2003

The use of differential pulse polarography (DPP) at the dropping mercury electrode (DME) to detect and to investigate the mechanisms for decomposition of arenediazonium ions, ArN2+, under different experimental conditions is discussed. The effect of a number of experimental and instrumental parameters on the polarographic peaks of a model arenediazonium ion was explored and representative applications to investigate their reaction mechanisms are given. The composite data shows that DPP provides an alternative, relatively cheap, technique to monitor ArN2+ decomposition in, for example, opaque systems where, for obvious reasons, spectroscopic detection does not work; meanwhile in homogeneous systems, DPP complements the results obtained by employing spectroscopic or chromatographic techniques. In addition, a variety of valuable mechanistic information such as detection of transient intermediates or estimation of the binding constants of aryl radicals with macromolecular systems, that otherwise cannot be easily obtained, is readily available by using DPP.
Partial filling‐micellar electrokinetic chromatography optimization studies of ibuprofen, codeine and degradation products, and coupling to mass spectrometry: Part II
Authors: Stubberud Karin , Callmer Karin , Westerlund Douglas
Published: March 2003

We describe the use of partial filling‐micellar electrokinetic chromatography‐mass spectrometry (PF‐MEKC‐MS) on the pharmaceutical ingredients ibuprofen and codeine phosphate as well as their degradation products and impurities. The study focuses on the change of the borate buffer to the volatile ammonium acetate and the optimization of critical MS parameters. The sensitivity of the method is also evaluated. The results are compared to an existing MEKC‐UV method that is used for quantitative determination of the two main substances as well as for the analysis of the degradation products. It is concluded that the PF‐MEKC‐MS system is suitable for separation and identification.
Detection of chlorinated quinones using interdigitated electrodes coupled with capillary electrophoresis
Authors: Male Keith B. , Luong John H. T.
Published: March 2003

An array of eight interdigitated microband gold electrodes (IDEs) has been developed together with electrophoretic separation for analysis of chlorinated hydroquinones (ClHQs) and benzoquinones (ClBQs). The IDE chip positioned very close to the separation capillary outlet served as an amplification/detection system without the requirement for frequent “capillary‐electrode” alignment. ClHQs, electrophoretically migrating to the IDE surface, were oxidized at +1.1 V by seven electrodes of the array and then detected by the remaining electrode, poised at –0.1 V. Conversely, ClBQs were detected at +1.1 V by the detecting electrode after having been reduced at the 7 adjacent electrodes poised at –0.1 V. There was an amplification effect on both the detecting electrode as well as the adjacent electrodes because of the recycle between ClHQs and ClBQs. The detecting “amplification” current response was dependent on the potentials applied, the position of the detecting electrode on the array, the number of adjacent electrodes being used for recycling and the distance between the oxidative and reductive electrodes. Micellar electrokinetic chromatography (MEKC) separation of the analytes was achieved using 30 mM sodium dodecyl sulfate (SDS) with a detection limit in the range of 2–20 μM. In addition to a facile “capillary‐electrode” alignment, the important aspect described here was the capability of detecting through recycling a reduced compound (in the case of ClHQs) at a negative potential to circumvent fouling and electroactive interferences. An appealing feature was also the concurrent oxidation/reduction detection for each compound to ascertain peak assignment, as interfering compounds are less likely to exhibit the same oxidative/reductive characteristics and electrophoretic mobilities as the target analytes.
On‐line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy
Authors: Fang Ching , Liu Ju‐Tsung , Lin Cheng‐Huang
Published: March 2003

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping‐micellar electrokinetic chromatography (MEKC) was used for the initial on‐line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on‐line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography‐mass spectrometry (GC‐MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC‐MS in such analyses.
Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography
Authors: Fang Ching , Liu Ju‐Tsung , Chou Shiu‐Huey , Lin Cheng‐Huang
Published: March 2003

The separation and on‐line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on‐line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping‐MEKC) and cation‐selective exhaustive injection‐sweep‐micellar electrokinetic chromatography (CSEI‐sweep‐MEKC) were applied; the optimum on‐line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; ∼1/10 to the value of LD50). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.
Analysis of lignans using micellar electrokinetic chromatography
Authors: Kuo Ching‐Hua , Lee Shoei‐Sheng , Chang Hsing‐Yun , Sun Shao‐Wen
Published: March 2003

Micellar electrokinetic chromatography (MEKC) was used to separate twelve lignan compounds originating from Phyllanthus plants. To increase the reliability of peak identification, two micellar systems, the sodium dodecyl sulfate (SDS) and sodium deoxycholate (SDC) systems, were investigated. Because of the high lipophilicity of the lignan analytes, tetrahydrofuran was added to the SDS micellar system to increase its separating ability. In contrast to SDS system, no organic solvent was needed with SDC micelles. Both micellar systems gave a satisfactory separation within a reasonable analysis time. On considering accuracy for quantitation, the SDS method was validated and then used to determine the content of the lignans in two Phyllanthus plants. The selectivity (elution order of the lignans) was significantly different between the SDS and SDC micellar systems. Retention in SDC‐MEKC seemed to be dominated by the hydrophobicity of the lignan solutes, while in SDS‐MEKC, retention was greatly influenced by hydrogen bonding interactions.
Enantiomeric separations using polymeric L‐glutamate surfactant derivatives: Effect of increasing steric factors
Authors: Thibodeaux Stefan J. , Billiot Eugene , Torres Eric , Valle Bertha C. , Warner Isiah M.
Published: March 2003

This study examines the role of steric hindrance near the stereogenic centers of four glutamic acid based polymeric surfactants. The single amino acid surfactants of glutamic acid, glutamic acid methyl ester, glutamic ethyl ester, and glutamic acid tert‐butyl ester were investigated. The micellar electrokinetic chromatography (MEKC) separation of three binaphthyl derivatives and three benzodiazepines were used to study these steric factors. In addition, the hydrophobicity of these polymers as a function of pH was investigated by use of fluorescence measurements.
Comparative enantioseparations with native β‐cyclodextrin, randomly acetylated β‐cyclodextrin and heptakis‐(2,3‐di‐O‐acetyl)‐β‐cyclodextrin in capillary electrophoresis
Authors: Chankvetadze Bezhan , Lomsadze Ketevan , Burjanadze Naira , Breitkreutz Joerg , Pintore Giorgio , Chessa Mario , Bergander Klaus , Blaschke Gottfried
Published: March 2003

Comparative enantioseparations were performed with three neutral cyclodextrins (CDs) in capillary electrophoresis (CE). In particular, native β‐CD was compared with single component heptakis(2,3‐di‐O‐acetyl)‐β‐CD (HDA‐β‐CD) and randomly acetylated β‐CD (Ac‐β‐CD) with the emphasis on the enantiomer migration order. The opposite affinity of the enantiomers of several chiral analytes was observed towards native β‐CD and its acetylated derivatives. The enantiomer affinity pattern of some chiral analytes was also opposite towards the two acetylated derivatives of β‐CD. In the case of the chiral drug clenbuterol (CL) an attempt was made to evaluate the possible structural reasons of the affinity reversal using one‐ and two‐dimensional as well as transverse rotating frame nuclear Overhauser effect spectroscopy (ROESY). Significant differences were observed between the structure of the CL complexes with β‐CD and HDA‐β‐CD.
Capillary electrophoretic separation of glutamate enantiomers in neural samples
Authors: Quan Zhe , Liu Yi‐Ming
Published: March 2003

A micellar electrokinetic chromatographic (MEKC) separation of glutamate (Glu) enantiomers fluorescently tagged with naphthalene‐2,3‐dicarboxaldehyde (NDA) is described. Chiral selectors tested included α‐, β‐, and γ‐cyclodextrins, modified cyclodextrins, D‐glucosamine, sucrose, taurocholate, and their binary mixtures. NDA‐labeled Glu enantiomers were best resolved with β‐cyclodextrin in the presence of methanol as an organic modifier. Under the separation conditions, no other amino acids coelute with Glu enantiomers. Using NDA as the reagent, the labeling reaction proceeded readily in aqueous solution, and the spectroscopic properties of NDA fluorophore were optimum for the sensitive laser‐induced fluorescence (LIF) detection. Glu enantiomers present in mass limited samples such as single neurons could be adequately quantified by coupling this separation with LIF detection. A detection limit of 0.57 μM Glu was obtained. Using the present method, D‐Glu was detected in rat brain, and, for the first time, in ganglia and single neurons of Aplysia californica, an extensively studied neuronal model. Interestingly, the level of D‐Glu was found to be higher than that of L‐Glu in many Aplysia neurons.
Flow‐through partial‐filling affinity capillary electrophoresis can estimate binding constants of neutral ligands to receptors via a competitive assay technique
Authors: Kaddis John , Mito Erica , Heintz Joseph , Plazas Alfredo , Gomez Frank A.
Published: March 2003

This work evaluates the use of a competitive binding assay using flow‐through partial‐filling affinity capillary electrophoresis (FTPFACE) to estimate binding constants of neutral ligands to a receptor. We demonstrate this technique using, as a model system, carbonic anhydrase B (CAB, EC 4.2.1.1) and arylsulfonamides. In this technique, the capillary is first partially filled with a negatively charged ligand, a sample containing CAB and two noninteracting standards, and a neutral ligand, then electrophoresed. Upon application of a voltage the sample plug migrates into the plug of negatively charged ligand (L–) resulting in the formation of a CAB‐L– complex. Continued electrophoresis results in mixing between the neutral ligand (L0) and the CAB‐L– complex. L0 successfully competes out L– to form the new CAB‐L0 complex. Analysis of the change in the relative migration time ratio (RMTR) of CAB relative to the noninteracting standards, as a function of neutral ligand concentration, yields a value for the binding constant. These values are in agreement with those estimated using other binding and ACE techniques. Data demonstrating the quantitative potential of this method is presented.
Electrophoretically mediated reaction of glycosidases at a nanoliter scale
Authors: Kanie Yoshimi , Kanie Osamu
Published: March 2003

We have investigated electrophoretically mediated microanalysis (EMMA) for the assay of a native glyco‐enzyme. As a representative of this class of enzyme, β‐glucosidase was selected, and the reaction was analyzed. Our EMMA was based on the plug‐plug interaction of enzyme and substrate plugs, which is essential to reduce quantities of materials. Furthermore, we have addressed the problem of incompatibility of the enzymatic reaction and separation of the reactants. As a result, EMMA of native glycosidase was achieved with a reaction volume of ∼ 20 nL and the Michaelis constant was estimated according to the Lineweaver‐Burk plot. The current method may have advantages over traditional assay methods, especially in terms of the amount of enzyme (ng order) and substrate (pmol order) required for a reaction*.
On‐line coupling of size‐exclusion chromatography and capillary zone electrophoresis via a reversed‐phase C18 trapping column for the determination of peptides in biological samples
Authors: Stroink Thom , Schravendijk Pim , Wiese Gerard , Teeuwsen Jan , Lingeman Henk , Waterval Joop C. M. , Bult Auke , de Jong Gerhardus J. , Underberg Willy J. M.
Published: March 2003

Since biologically active peptides usually exhibit their effects in low concentrations, the development of sensitive analytical methods has become a challenge. In this paper, a multidimensional system is presented, consisting of a size‐exclusion chromatographic (SEC) separation followed by a trapping procedure on a 4 mm×3 mm ID reversed‐phase C18 (RP18) column with subsequent elution of the trapped fraction and separation by capillary zone electrophoresis (CZE). The system has been tested with mixtures of six enkephalins and albumin, mimicking biological matrices such as plasma and cerebrospinal fluid. After separation of albumin from the enkephalins in the SEC dimension a heart‐cut of 200 μL, containing the enkephalin peak, is taken, concentrated on the RP18 microcolumn and, after elution with a 20 μL plug of 80% acetonitrile, electrokinetically injected into the CZE system, where stacking and separation is achieved. While validation shows generally good linearity and reproducibility, the quantitation limit with UV detection is acceptable (2.5 μg/ mL with an injection volume of 50 μL).
Advances in capillary electrochromatography and micro‐high performance liquid chromatography monolithic columns for separation science
Authors: Legido‐Quigley Cristina , Marlin Nicola D. , Melin Virginie , Manz Andreas , Smith Norman W.
Published: March 2003

Over the last decade, monoliths or continuous beds have emerged as an alternative to traditional packed‐bed columns for use in capillary electrochromatography (CEC) and micro‐high performance liquid chromatography (μ‐HPLC). Monolithic columns can be divided into two categories: silica‐based monolithic columns and rigid organic polymer‐based monolithic columns resulting from the polymerization of acrylamide, styrene, acrylate or methacrylate monomers. In this paper, the chemistry and most recent applications of these various types of monoliths in both CEC and μ‐HPLC are presented.
Separation of selected humic degradation compounds by capillary electrochromatography with monolithic and packed columns
Authors: Ping Guichen , Schmitt‐Kopplin Philippe , Hertkorn Norbert , Zhang Weibing , Zhang Yukui , Kettrup Antonius
Published: March 2003

The separation of selected lignin/humic substance (HS) degradation compounds by capillary electrochromatography (CEC) with a methacrylate‐based monolithic column and a conventional column packed with 5 μm octadecyl silica (ODS) particles is presented. The effects of organic modifier concentration, pH of the mobile phase, ionic strength, applied voltage, and temperature on the separation were investigated to determine the optimal separation conditions. With the increase of pH in the mobile phase, some of analytes start to ionize and both chromatographic partition and electrophoresis can play roles in separation simultaneously. Accordingly, different selectivity from high‐performance liquid chromatography (HPLC) and capillary electrophoresis (CE) could be achieved. The performances of both kinds of columns were compared. The results showed that the peaks of compounds obtained on the former column were much wider than those on the latter one, although good separation efficiency of alkylbenzenes could be readily achieved; the most probable reasons for this behavior and method to solve this problem were briefly discussed. The CEC of a soil fulvic acid with a monolithic column produced partly resolved broad bands; by means of nuclear magnetic resonance (NMR) analysis a wide range of oxygen derived aromatic substitution patterns was found with prominent contributions from phenolic and carboxylic groups.
Capillary electrochromatographic analysis of aliphatic mono‐ and polycarboxylic acids
Authors: Chen Wei‐Hsi , Lin Chun‐Chi , Chen Tse‐Shien , Misra Tarun K. , Liu Chuen‐Ying
Published: March 2003

The parameters influencing the electrochromatographic separation of aliphatic organic acids in a capillary column with a wall‐coated macrocyclic polyamine have been studied. Indirect detection using chromate, pyromellitate, trimellitate, o‐phthalate, benzoate and acetate as background electrolytes has been tested. A complete separation of polyprotic acids could be achieved with pyromellitate buffer (7.5 mM, pH 6.5), and satisfactory results for the simultaneous separation of monoprotic acids and polyprotic acids were found using a capillary column of 70 cm (50 cm effective length)×75 μm inner diameter, electrokinetic injection (–10 kV, 10 s), benzoate buffer (6 mM, pH 4.6), separation voltage of –10 kV, and detection at 220 nm. For the separation of the geometric isomers fumarate and maleate, acetate buffer was found the best choice among the background electrolytes tested. The method so established has been applied to the determination of organic acids in soy sauce, brandy, lemon juice, spinach juice and cigarette. From the retention behavior, it was found that the separation mechanism on the bonded phase was influenced by the macrocyclic effect, electrostatic attraction, hydrogen bonding, van der Waals forces, and anion exchange, in addition to the differences in electrophoretic mobility.
Comparison of the retention characteristics of different pseudostationary phases for microemulsion and micellar electrokinetic chromatography of betamethasone and derivatives
Authors: Lucangioli Silvia E. , Carducci Clyde N. , Scioscia Silvia L. , Carlucci Adriana , Bregni Carlos , Kenndler Ernst
Published: March 2003

Five electrokinetic chromatography systems were compared concerning retention behavior and lipophilicity. Comparison was based on capacity (retention) factors of some steroidal drugs, and on log POW values derived by the aid of reference substances. In all systems the aqueous buffer consisted of phosphate (20 mM, pH 7.5). Two systems had micelles, three systems microdroplets as negatively charged pseudostationary phases. The micelles were formed by sodium dodecyl sulfate (SDS) and sodium cholate, respectively. One microemulsion consisted (as usual) from octane as oil, butanol as cosurfactant and SDS as charged tenside. Two microemulsions were made from biosurfactants (phosphatidylcholine, isopropylmyristate) to better simulate biopartitioning of the drugs. Even for noncharged analytes a change in migration sequence and thus in log POW was observed for the systems consisting of the biosurfactants, compared to the others. For the former systems, log POW derived from the capacity factors agree for all analytes with those obtained from calculation by computer software based on the structure of the drugs, and with experimental data directly obtained from octanol/water partitioning.
Microemulsion electrokinetic chromatography applied for separation of levetiracetam from other antiepileptic drugs in polypharmacy
Authors: Ivanova Mariela , Piunti Alessandra , Marziali Ettore , Komarova Natalja , Raggi Maria Augusta , Kenndler Ernst
Published: March 2003

Microemulsion electrokinetic chromatography was applied for the separation of levetiracetam from other antiepileptic drugs (primidone, phenobarbital, phenytoin, lamotrigine and carbamazepine) that are potentially coadministered in therapy of patients. The influence of the composition of the microemulsion system (with sodium dodecyl sulfate as charged surfactant) was investigated, modifying the kind of cosurfactant (lower alcohols from C3 to C5), the pH (and salinity) of the aqueous background electrolyte, and the ratio of aqueous phase to organic constituents forming the microdroplets of the oil‐in‐water emulsion. Separation selectivity was depending on all these parameters, resulting even in changes of the migration sequence of the analytes. Only moderate correlation was observed for the microemulsion system compared with a micellar system, both consisting of the aqueous borate buffer (pH 9.2) and SDS as micelle former (linear correlation coefficient for analyte mobilities is 0.974). The sample solvent plays an important role on the shape of the resulting chromatograms: methanol at concentrations higher than 35% impairs peak shape and separation efficiency. The microemulsion method (with 93.76% aqueous borate buffer (pH 9.2, 10 mM), 0.48% n‐octane, 1.80% SDS, 3.96% 1‐butanol, all w/w) is suitable for the determination of levetiracetam in human plasma (combined with a sample pretreatment based on solid‐phase extraction).
Three‐dimensional transient free‐surface flow of viscous fluids inside cavities of arbitrary shape
Authors: Kim Kyu‐Tae , Khayat Roger E.
Published: March 2003

The three‐dimensional transient free‐surface flow inside cavities of arbitrary shape is examined in this study. An adaptive (Lagrangian) boundary‐element approach is proposed for the general three‐dimensional simulation of confined free‐surface flow of viscous incompressible fluids. The method is stable as it includes remeshing capabilities of the deforming free‐surface, and thus can handle large deformations. A simple algorithm is developed for mesh refinement of the deforming free‐surface mesh. Smooth transition between large and small elements is achieved without significant degradation of the aspect ratio of the elements in the mesh. The method is used to determine the flow field and free‐surface evolution inside cubic, rectangular and cylindrical containers. These problems illustrate the transient nature of the flow during the mixing process. Surface tension effects are also explored. Copyright © 2003 John Wiley & Sons, Ltd.
Anisotropic Cartesian grid method for steady inviscid shocked flow computation
Authors: Wu Zi‐Niu , Li Ke
Published: March 2003

The anisotropic Cartesian grid method, initially developed by Z.N. Wu (ICNMFD 15, 1996; CFD Review 1998, pp. 93–113) several years ago for efficiently capturing the anisotropic nature of a viscous boundary layer, is applied here to steady shocked flow computation. A finite‐difference method is proposed for treating the slip wall conditions. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical approximation of generalized Newtonian fluids using Powell–Sabin–Heindl elements: I. theoretical estimates
Authors: Chow S.‐S. , Carey G. F.
Published: March 2003

In this paper we consider the numerical approximation of steady and unsteady generalized Newtonian fluid flows using divergence free finite elements generated by the Powell–Sabin–Heindl elements. We derive a priori and a posteriori finite element error estimates and prove convergence of the method of successive approximations for the steady flow case. A priori error estimates of unsteady flows are also considered. These results provide a theoretical foundation and supporting numerical studies are to be provided in Part II. Copyright © 2003 John Wiley & Sons, Ltd.
Large‐eddy simulation with complex 2‐D geometries using a parallel finite‐element/spectral algorithm
Authors: Snyder D. O. , Degrez G.
Published: March 2003

A parallel stabilized finite‐element/spectral formulation is presented for incompressible large‐eddy simulation with complex 2‐D geometries. A unique discretization scheme is developed consisting of a streamline‐upwind Petrov–Galerkin/Pressure‐Stabilized Petrov–Galerkin (SUPG/PSPG) finite‐element discretization in the 2‐D plane with a collocated spectral/pseudospectral discretization in the out‐of‐plane direction. This formulation provides an efficient approach for solving 3‐D flows over arbitrary 2‐D geometries. Utilizing this discretization and through explicit temporal treatment of the non‐linear terms, the system of equations for each Fourier mode is decoupled within each time step. A novel parallelization approach is then taken, where the computational work is partitioned in Fourier space. A validation of the algorithm is presented via comparison of results for flow past a circular cylinder with published values for Re=195, 300, and 3900. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical simulation of vortical ideal fluid flow through curved channel
Authors: Moshkin N. P. , Mounnamprang P.
Published: March 2003

A numerical algorithm to study the boundary‐value problem in which the governing equations are the steady Euler equations and the vorticity is given on the inflow parts of the domain boundary is developed. The Euler equations are implemented in terms of the stream function and vorticity. An irregular physical domain is transformed into a rectangle in the computational domain and the Euler equations are rewritten with respect to a curvilinear co‐ordinate system. The convergence of the finite‐difference equations to the exact solution is shown experimentally for the test problems by comparing the computational results with the exact solutions on the sequence of grids. To find the pressure from the known vorticity and stream function, the Euler equations are utilized in the Gromeka–Lamb form. The numerical algorithm is illustrated with several examples of steady flow through a two‐dimensional channel with curved walls. The analysis of calculations shows strong dependence of the pressure field on the vorticity given at the inflow parts of the boundary. Plots of the flow structure and isobars, for different geometries of channel and for different values of vorticity on entrance, are also presented. Copyright © 2003 John Wiley & Sons, Ltd.
Riemann solvers and boundary conditions for two‐dimensional shallow water simulations
Authors: Guinot Vincent
Published: March 2003

Most existing algorithms for two‐dimensional shallow water simulations treat multi‐dimensional waves using wave splitting or time splitting. This often results in anisotropy of the computed flow. Both wave splitting and time splitting are based on a local decomposition of the multi‐dimensional problem into one‐dimensional, orthogonal problems. Therefore, these algorithms handle boundary conditions in a very similar way to classical one‐dimensional algorithms. This should be expected to trigger a dependence of the number of boundary conditions on the direction of the flow at the boundaries. However, most computational codes based on alternate directions do not exhibit such sensitivity, which seems to contradict the theory of existence and uniqueness of the solution. The present paper addresses these issues. A Riemann solver is presented that aims to convert two‐dimensional Riemann problems into a one‐dimensional equivalent Riemann problem (ERP) at the interfaces between the computational cells. The ERP is derived by applying the theory of bicharacteristics at each end of the interface and by performing a linear averaging along the interface. The proposed approach is tested against the traditional one‐dimensional approach on the classical circular dambreak problem. The results show that the proposed solver allows the isotropy of the solution to be better preserved. Use of the two‐dimensional solver with a first‐order scheme may give better results than use of a second‐order scheme with a one‐dimensional solver. The theory of bicharacteristics is also used to discuss the issue of boundary conditions. It is shown that, when the flow is subcritical, the number of boundary conditions affects the accuracy of the solution, but not its existence and uniqueness. When only one boundary condition is to be prescribed, it should not be the velocity in the direction parallel to the boundary. When two boundary conditions are to be prescribed, at least one of them should involve the component of the velocity in the direction parallel to the boundary. Copyright © 2003 John Wiley & Sons, Ltd.
A robust multi‐grid pressure‐based algorithm for multi‐fluid flow at all speeds
Authors: Darwish M. , Moukalled F. , Sekar B.
Published: March 2003

This paper reports on the implementation and testing, within a full non‐linear multi‐grid environment, of a new pressure‐based algorithm for the prediction of multi‐fluid flow at all speeds. The algorithm is part of the mass conservation‐based algorithms (MCBA) group in which the pressure correction equation is derived from overall mass conservation. The performance of the new method is assessed by solving a series of two‐dimensional two‐fluid flow test problems varying from turbulent low Mach number to supersonic flows, and from very low to high fluid density ratios. Solutions are generated for several grid sizes using the single grid (SG), the prolongation grid (PG), and the full non‐linear multi‐grid (FMG) methods. The main outcomes of this study are: (i) a clear demonstration of the ability of the FMG method to tackle the added non‐linearity of multi‐fluid flows, which is manifested through the performance jump observed when using the non‐linear multi‐grid approach as compared to the SG and PG methods; (ii) the extension of the FMG method to predict turbulent multi‐fluid flows at all speeds. The convergence history plots and CPU‐times presented indicate that the FMG method is far more efficient than the PG method and accelerates the convergence rate over the SG method, for the problems solved and the grids used, by a factor reaching a value as high as 15. Copyright © 2003 John Wiley & Sons, Ltd.
Role of the α‐chemokine stromal cell‐derived factor (SDF‐1) in the developing and mature central nervous system
Authors: Lazarini Françoise , Tham To Nam , Casanova Philippe , Arenzana‐Seisdedos Fernando , Dubois‐Dalcq Monique
Published: March 2003

α‐chemokines, which control the activation and directed migration of leukocytes, participate in the inflammatory processes in host defense response. One of the α‐chemokines, CXCL12 or stromal cell‐derived factor 1 (SDF‐1), not only regulates cell growth and migration of hematopoietic stem cells but may also play a central role in brain development as we discuss here. SDF‐1 indeed activates the CXCR4 receptor expressed in a variety of neural cells, and this signaling results in diverse biological effects. It enhances migration and proliferation of cerebellar granule cells, chemoattracts microglia, and stimulates cytokine production and glutamate release by astrocytes. Moreover, it elicits postsynaptic currents in Purkinje cells, triggers migration of cortical neuron progenitors, and produces pain by directly exciting nociceptive neurons. By modulating cell signaling and survival during neuroinflammation, SDF‐1 may also play a role in the pathogenesis of brain tumors, experimental allergic encephalitis, and the nervous system dysfunction associated with acquired immunodeficiency syndrome. GLIA 42:139–148, 2003. © 2003 Wiley‐Liss, Inc.