bluuebunny/crossref_metadata_2025_split huggingface dataset:
Links between childbearing age and observed maternal behaviors with 14‐month‐olds in the Early Head Start Research and Evaluation Project
Authors: Berlin Lisa J. , Brady‐Smith Christy , Brooks‐Gunn Jeanne 
Published: August 2002

AbstractTeenage parents are commonly characterized as poor, minority, single mothers with low levels of education and problematic parenting behaviors. The role of teenage childbearing per se in mothers' parenting behaviors, however, is not well understood. This study addressed links between maternal childbearing age and parenting behaviors among 1,702 low‐income mothers participating in the Early Head Start Research and Evaluation Project. The sample includes White (n = 704), Black (n = 595), and Latina (n = 403) mothers. One third of the sample were teenage childbearers (younger than 19 years at the birth of the target child). When the children were 14 months old, mothers and children were videotaped in their home during a 10‐min free play assessment. This study examined four key parenting behaviors coded from this assessment: supportiveness, detachment, intrusiveness, and negative regard/hostility. Findings indicate that teenage childbearers were significantly less supportive, more detached, more intrusive, and more negative/hostile with their infants than older childbearers. Associations held above and beyond the effects of race/ethnicity, education, family type, family income, and child sex and age for supportiveness, detachment, and intrusiveness (but not negative regard/hostility). These findings provide the most definitive evidence to date of differences between teenage and older mothers' parenting behaviors, above and beyond demographic co‐factors. Within‐group analyses revealed different patterns of association in the three racial/ethnic groups. ©2002 Michigan Association for Infant Mental Health.
Antecedents of mirror self‐recognition of toddlers: Emotional availability, birth order, and gender
Authors: Harel Judith , Eshel Yohanan , Ganor Osnat , Scher Anat 
Published: August 2002

AbstractThe present study employed a longitudinal design for examining the role of emotional availability of child–mother dyads, birth order of children, and their gender as determinants of mirror self‐recognition of toddlers. It was hypothesized that toddlers who maintained more optimal emotional availability with mother at the age of 12 months would tend to identify themselves more readily at the age of 20 months. We assumed further that first‐born children and females would identify themselves more readily than males and younger siblings. A sample of 54 nonrisk children and their mothers was investigated. Path analysis model showed that emotional availability partly predicted self‐recognition: responsive toddlers identified themselves more often than less responsive peers. No significant effects were found for the other scales of emotional availability. A nonlinear birth order effect was observed, with second‐born children being less likely to show mirror self‐recognition than first‐borns or third‐borns. Child gender was not significantly associated with self‐recognition at the age of 20 months. The data showed further that birth order was significantly linked with components of emotional availability. No significant correlations were found between emotional availability scores and child gender. Results were discussed in light of the different components of emotional availability, and the psychological correlates of ordinal position in the family. ©2002 Michigan Association for Infant Mental Health.
Concrete canal lining cracking in low to medium plastic soils
Authors: Rahimi H. , Barootkoob SH. 
Published: August 2002

AbstractFailure of concrete irrigation canal linings in the form of cracking, rupture, uplifting and opening of joints, causes loss of water and money in many countries. Following the appearance of extensive cracking of concrete linings in one of the Shoeybieh sugar cane industry farms in the Khoozestan province of Iran, extensive research work was conducted to identify the main causes. In this paper, the final results of the research are presented.The testing program consisted of laboratory as well as field tests, including identification, chemical and mechanical tests of soil samples taken from the borrow pits and canal embankments. Dispersivity tests were performed using pin‐hole and chemical methods. Swelling tests were conducted using the ASTM standard and ISSMFE method. The field test includes measurement of deformations of the concrete lining and embankment of an actual lined canal resulting from the filling of the canal with water. The canal was 60 m in length. The deformations were recorded by surveying the elevations of steel bars driven to different depths under the canal lining and at different points in the canal and its embankment sections.The results of laboratory tests showed the soil to have low to medium plasticity with a classification of CL‐ML, having less than 1% soluble content, and being nondispersive. Swelling tests conducted by the ASTM and ISSMFE methods showed completely different results. The ISSMFE method resulted in a high free swell potential, while the ASTM method indicated a low to medium potential. The results of full‐scale field tests were all in favor of the ISSMFE method. The greatest difference between the results of the two methods was found to be due to the different compaction methods used during construction of the canal, as well as the moisture content of the soil sample being prepared for the swell tests.The flocculent structure and lower compaction water content of soil samples in the ISSMFE method resulted in much higher free swell. The similarity between compaction methods used in the field and the static effort used in the ISSMFE method, as well as very low soil water content of the canal embankments during lining operations, were found to be the main reasons for swelling of the soil and the eventual cracking of the concrete linings. Copyright © 2002 John Wiley & Sons, Ltd.
Income distribution and income dynamics in the United Kingdom
Authors: Dutta Jayasri , Sefton J. A. , WEALE M. R. 
Published: August 2002

AbstractIn this paper, we propose a model of income dynamics which takes account of mobility both within and between jobs. The model is a hybrid of the mover‐stayer model of income dynamics and a geometric random walk. In any period, individuals face a discrete probability of ‘moving’, in which case their income is a random drawn from a stationary recurrent distribution. Otherwise, they ‘stay’ and incomes follow a geometric random walk. The model is estimated on income transition data for the United Kingdom from the British Household Panel Survey (BHPS) and provides a good explanation of observed non‐linearities in income dynamics. The steady‐state distribution of the model provides a good fit for the observed, cross‐sectional distribution of earnings. We also evaluate the impact of tertiary education on income transitions and on the long‐run distribution of incomes. Copyright © 2001 John Wiley & Sons, Ltd.
In vitro hepatotoxicity of alachlor and its by‐products
Authors: El‐Sakka Sahar , Salem Ezz El‐Din M. , Abdel‐Rahman Mohamed S. 
Published: August 2002

AbstractDuring water treatment, potentially hazardous chemical by‐products may be formed. Alachlor (2‐chloro‐N‐(2, 6‐diethylphenyl)‐N‐(methoxymethyl) acetamide) is a widely used pre‐emergence herbicide. The present study investigated the toxicity of alachlor and its disinfection by‐products on freshly isolated rat hepatocytes. Hepatocytes were harvested by a collagenase perfusion technique and were exposed to different concentrations of alachlor and its by‐products for up to 2 h. Cell viability, the leakage of aspartate transaminase (AST) and alanine transaminase (ALT) and glutathione (GSH) depletion were determined throughout the incubation period. The cell viability of the hepatocytes exposed to 100 µg ml−1 alachlor was decreased by 20% compared with the control after 60 min of incubation. At the same concentration of alachlor the leakage of ALT and AST was increased by 56% and 45%, respectively. Cell viability of the hepatocytes was decreased upon exposure to 2‐chloro‐N‐(3‐chloro‐2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide (CCDMA) and 2‐chloro‐N‐(3‐chloro‐2,6‐diethylphenyl) acetamide (CCDA)—the by‐products of alachlor and chlorine—after 60 min of exposure. At 100 µg ml−1 CCDMA the AST leakage was increased significantly (73%) after 30 min of incubation. The reaction mixture of alachlor (100 µg ml−1) and chlorine dioxide (1 ppm) caused significant increases in cell loss and ALT and AST levels by 22%, 40% and 34%, respectively, as early as 15 min incubation. Alachlor (100 and 200 µg ml−1) caused significant decreases in GSH contents (62%) in isolated hepatocytes. The reaction mixture of alachlor and chlorine dioxide led to significant glutathione depletion (44%) after 60 min of incubation. The by‐products of alachlor and chlorine—CCDMA and CCDA—depleted GSH almost completely (93%). This investigation suggested that the by‐products formed from the reaction of alachlor and chlorine decreased GSH and increased the leakage of liver enzymes, especially AST. Copyright © 2002 John Wiley & Sons, Ltd.
Morphologic and functional evaluation of peripheral nerve fibers regenerated through polyimide sieve electrodes over long‐term implantation
Authors: Ceballos Dolores , Valero‐Cabré Antoni , Valderrama Elena , Schüttler Martin , Stieglitz Thomas , Navarro Xavier 
Published: August 2002

AbstractWe evaluated by morphologic and functional analysis the regeneration of peripheral nerve fibers through polyimide regenerative‐type electrodes over long‐term implantation. Polyimide sieve electrodes were placed in silicone chambers and implanted between the severed ends of the sciatic nerve in rats. The sieve part had 281 round via holes of 40 μm in diameter, with nine integrated recording–stimulating electrodes arranged around the via holes. The degree of axonal regeneration was examined at 2, 7, and 12 months postimplantation (mpi). Regeneration was successful in 12 of the13 animals implanted. Reinnervation of distal muscle and nerves increased with time, reaching a plateau about 7 mpi. The number of myelinated fibers increased from 2 to 7 months, at which time it was similar to control values. With time the myelinated fibers matured, with significant increases in axon diameter and myelin thickness. Only 0.6% of the regenerated axons showed evidence of compression near the implanted electrode. The majority of the myelinated fibers that crossed the via holes and had been regenerated through the distal nerve had a normal appearance. Sieve electrodes were useful for nerve stimulation at postimplantation. Stimulation through different active electrodes excited nerve bundles, evoking compound muscle action potentials of varying shape and amplitude, indicative of selective axonal stimulation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 517–528, 2002
Effects of ion concentration and pH on hydroxyapatite deposition from aqueous solution onto titanium by the thermal substrate method
Authors: Kuroda Kensuke , Ichino Ryoichi , Okido Masazumi , Takai Osamu 
Published: August 2002

AbstractA new hydrocoating method (the thermal substrate method) has been proposed for coating calcium phosphates, such as hydroxyapatite, onto titanium substrates in an aqueous solution. The influences of several solution properties on the thermal substrate method were examined. The solutions used included 3 mmol dm−3 Ca(H2PO4)2 and 7 mmol dm−3 CaCl2 as a reference concentration solution. The ion concentration was changed from 0.1 to 2 times with respect to the reference concentration. The experimental studies were conducted under the following conditions: temperature = 140°C, heating time = 10–20 min., pH = 4–8 and Ca/P = 0.0167–16.7. The type of precipitate changed, depending on the pH and ion concentration. In the reference solution with pH > 6, predominantly hydroxyapatite was precipitated onto titanium. By contrast, only CaHPO4 was formed in the solution of pH 4. In the solution with an ion concentration of one‐tenth the reference solution, CaHPO4 was also precipitated. The addition of H3PO4 to the 0.1‐times solution accelerated the precipitation rate of HA. It is suggested that the PO43− concentration was insufficient to form HA in the Ca/P = 1.67 solution. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 354–359, 2002
Questionable efficacy of plasma exchange for thrombotic thrombocytopenic purpura after bone marrow transplantation
Authors: Teruya J. , Styler M. , Verde S. , Topolsky D. , Crilley P. 
Published: August 2002

AbstractThrombotic thrombocytopenic purpura (TTP) after bone marrow transplantation (BMT) is an uncommon complication presumably associated with extensive endothelial cell damage due to Cyclosporine, total body irradiation, or other drugs. While the majority of patients with primary TTP, which is considered to be an autoimmune process, respond to plasma exchange, TTP after BMT has a very poor prognosis. A total of 7 patients out of 307 patients who underwent BMT were diagnosed with TTP during 1989–1999. The diagnosis of TTP was made based on thrombocytopenia and microhemangiopathic hemolytic anemia characterized by an elevated LDH and the presence of schistocytes on the peripheral blood smear. Five patients were treated with plasma exchange (PE) using fresh frozen plasma and/or cryoprecipitate poor plasma as replacement fluid. One patient was treated using a protein A column. One patient did not receive plasma exchange because the 125 patient was clinically stable and was discharged. It was hard to assess the efficacy of PE due to the multiplicity of the patients' clinical condition and laboratory data. At least 4 patients did not respond to PE and 2 patients were not able to be evaluated due to multi organ failure. However, all patients died. It is not clear at this moment if PE for patients with TTP after BMT is truly beneficial. J. Clin. Apheresis 16:169–174, 2001. © 2001 Wiley‐Liss, Inc.
A new continuous‐flow cell separation method based on cell density: Principle, apparatus, and preliminary application to separation of human buffy coat
Authors: Ito Yoichiro , Shinomiya Kazufusa 
Published: August 2002

AbstractWith the recent progress in transfusion medicine, separation and isolation of cells in a large quantity is becoming increasingly important. At present, the continuous cell separation method in a preparative scale is limited to apheresis and elutriation: the former is mainly used for collection of platelet and buffy coat from the whole blood, while the latter separates cells virtually according to their size. Here we introduce a continuous flow method that separates cells entirely based on cell density. The method is gentle and capable of processing a large number of cells. The potential capability of the method was demonstrated on separation of lymphocytes and granulocytes from human buffy coat. Lymphocytes were enriched to 90% in the fraction at density = 1.065 and granulocytes are isolated in fractions at density = 1.075–1.080 while red cells were completely retained at the periphery of the channel. CD34 cells were distributed around 1.065 and coeluted with lymphocytes, suggesting that further enrichment requires focusing the density gradient around 1.070. The method could process 109 nucleated cells in 2 hours. Our preliminary results suggest that the present method is an effective and efficient means to separate blood cells. J. Clin. Apheresis 16:186–191, 2001. Published 2001 Wiley‐Liss, Inc.
Evidence for selective induction of phosphoenolpyruvate carboxykinase gene expression by unsaturated and nonmetabolized fatty acids in adipocytes
Authors: Duplus Eric , Glorian Martine , Tordjman Joan , Berge Rolf , Forest Claude 
Published: August 2002

AbstractPolyunsaturated fatty acids (PUFAs) and 3‐thia fatty acids are hypolipidemic and decrease insulin resistance in Type II diabetic animals. To exert such an action, these FAs could decrease adipose tissue lipolysis or increase esterification. Glyceroneogenesis is an important metabolic pathway in adipocytes for re‐esterification of FAs originating from lipolysis and in hepatocytes for triacylglycerol synthesis during fasting. Cytosolic phosphoenolpyruvate carboxykinase (PEPCK) plays a key role in this pathway. Here we show that the PUFA docosahexaenoic acid (DHA) stimulates PEPCK mRNA in glucose‐deprived adipose tissue explants from fed rats and in 3T3‐F442A differentiated adipocytes. This effect is maximum at 3 h, stable up to at least 11 h of treatment, and affects the transcription of the gene. PEPCK mRNA half‐life is not affected. Among a series of adipocyte transcripts, only the adipocyte lipid binding protein mRNA is also increased by DHA, although later than the PEPCK mRNA and at a much lower extent. DHA has no effect on PEPCK gene expression in the H4IIE hepatoma cells in which this gene is responsive to other inducers like cAMP. This lack of effect is not due to a failure of DHA to act in H4IIE cells since it induces the carnitine palmitoyltransferase 1 (CPT‐1) mRNA. Therefore, the DHA effect appears to be cell‐selective. Results of experiments using either tetradecylthio acetic acid and α‐bromopalmitate, two nonmetabolized Fas, or a series of inhibitors of FA metabolism show that the FA effect on PEPCK mRNA is not due to a product of its metabolism. Hence, polyunsaturated and nonmetabolized FAs stimulate adipose PEPCK, therefore potentially enhancing glyceroneogenesis and reducing FA output. This mechanism could participate in the hypolipidemic action of PUFAs. J. Cell. Biochem. 85: 651–661, 2002. © 2002 Wiley‐Liss, Inc.
Trichostatin a inhibits β‐casein expression in mammary epithelial cells
Authors: Pujuguet Philippe , Radisky Derek , Levy Dinah , Lacza Charlemagne , Bissell Mina J. 
Published: August 2002

AbstractMany aspects of cellular behavior are defined by the content of information provided by association of the extracellular matrix (ECM) and with cell membrane receptors. When cultured in the presence of laminin‐containing ECM and prolactin (Prl), normal mammary epithelial cells express the milk protein β‐casein. We have previously found that the minimal ECM‐ and Prl‐responsive enhancer element BCE‐1 was only active when stably integrated into chromatin, and that trichostatin A (TSA), a reagent that leads to alterations in chromatin structure, was able to activate the integrated enhancer element. We now show that endogenous β‐casein gene, which is controlled by a genetic assembly that is highly similar to that of BCE‐1 and which is also activated by incubation in ECM and Prl, is instead inhibited by TSA. We provide evidence that the differing response of β‐casein and BCE‐1 to TSA is neither due to an unusual effect of TSA on mammary epithelial cells, nor to secondary consequences from the expression of a separate gene, nor to a particular property of the BCE‐1 construct. As a component of this investigation, we also showed that ECM mediated rapid histone deacetylation in mammary epithelial cells. These results are discussed in combination with previous work showing that TSA mediates the differentiation of many types of cancer cells but inhibits differentiation of some nonmalignant cell types. J. Cell. Biochem. 83: 660–670, 2001. © 2001 Wiley‐Liss, Inc.
Can we understand the different coordinations and structures of closed‐shell metal cation‐water clusters?
Authors: Derepas A.‐L. , Soudan J.‐M. , Brenner V. , Dognon J.‐P. , Millié Ph. 
Published: August 2002

AbstractWe present a model potential for studying Mq+(H2O)n=1,9 clusters where M stands for either Na+, Cs+, Ca2+, Ba2+, or La3+. The potential energy surfaces (PES) are explored by the Monte Carlo growth method. The results for the most significant equilibrium structures of the PES as well as for energetics are favorably compared to the best ab initio calculations found in the literature and to experimental results. Most of these complexes have a different coordination number in cluster compared to experimental results in solution or solid phase. An interpretation of the coordination number in clusters is given. In order to well describe the transition between the first hydration sphere and the second one we show that an autocoherent treatment of the electric field is necessary to correctly deal with polarization effects. We also explore the influence of the cation properties (charge, size, and polarizability) on both structures and coordination number in clusters, as well as the meaning of the second hydration sphere. Such an approach shows that the leading term in the interaction energy for a molecule in the second hydration sphere is an electrostatic attraction to the cation and not a hydrogen bond with the water molecules in the first hydration sphere. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1013–1030, 2002
Quantum chemical calculation of vibrational spectra of large molecules—Raman and IR spectra for Buckminsterfullerene
Authors: Neugebauer Johannes , Reiher Markus , Kind Carsten , Hess Bernd A. 
Published: August 2002

AbstractIn this work we demonstrate how different modern quantum chemical methods can be efficiently combined and applied for the calculation of the vibrational modes and spectra of large molecules. We are aiming at harmonic force fields, and infrared as well as Raman intensities within the double harmonic approximation, because consideration of higher order terms is only feasible for small molecules. In particular, density functional methods have evolved to a powerful quantum chemical tool for the determination of the electronic structure of molecules in the last decade. Underlying theoretical concepts for the calculation of intensities are reviewed, emphasizing necessary approximations and formal aspects of the introduced quantities, which are often not explicated in detail in elementary treatments of this topic. It is shown how complex quantum chemistry program packages can be interfaced to new programs in order to calculate IR and Raman spectra. The advantages of numerical differentiation of analytical gradients, dipole moments, and static, as well as dynamic polarizabilities, are pointed out. We carefully investigate the influence of the basis set size on polarizabilities and their spatial derivatives. This leads us to the construction of a hybrid basis set, which is equally well suited for the calculation of vibrational frequencies and Raman intensities. The efficiency is demonstrated for the highly symmetric C60, for which we present the first all‐electron density functional calculation of its Raman spectrum. © 2002 Wiley Periodicals, Inc. J Comput Chem 9: 895–910, 2002
Molecular mechanics calculations on carbonyl compounds. III. Cycloketones
Authors: Langley Charles H. , Lii Jenn‐Huei , Allinger Norman L. 
Published: August 2002

AbstractMolecular mechanics (MM4) calculations were carried out on cycloketones for ring sizes ranging from 4 to 11 carbon atoms. The MM4 relative energies for the various conformations of the cycloketones were compared to density functional theory (DFT) calculations (B3LYP/6‐31G*), which were also carried out in this work. For small ring sizes (n=4–6), calculated molecular geometries, dipole moments, moments of inertia, and vibrational spectra were compared to experimental data. The axial–equatorial energy differences in methyl‐substituted cyclohexanones were also calculated by MM4 and compared to ab initio, DFT, and experimental results. The results of the MM4 studies on cycloketones showed significant improvement from those of MM3 calculations performed in parallel with the MM4 calculations. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1451–1475, 2001