bluuebunny/crossref_metadata_2025 huggingface dataset:
A Mixed Ruthenium Polypyridyl Complex Containing a PEG‐Bipyridine Macroligand
Authors: Marin Veronica , Holder Elisabeth , Meier Michael A. R. , Hoogenboom Richard , Schubert Ulrich S.
Published: March 2004

Summary: An amino‐functionalized bipyridine ligand was prepared in order to serve as a bridging unit to an activated low‐molecular‐weight monomethyl ether of poly(ethylene glycol) (PEG). Coordination of a ruthenium(II) phenantroline precursor onto the formed PEG‐containing bipyridine ligand yielded a metal‐containing polymer which shows interesting properties for solar cell applications.

A schematic of the described polymeric ruthenium(II) complex and its absorption and emission properties.

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A schematic of the described polymeric ruthenium(II) complex and its absorption and emission properties.
Effects of the Bead‐Solvent Interaction on the Dynamics of Macromolecules, 1
Authors: Uvarov Alexander , Fritzsche Stephan
Published: March 2004

Summary: Hamiltonian dynamics and a chain model are used to study the dynamics of macromolecules immersed in a solution. From the Hamiltonian of the overall system, “macromolecule + solvent,” a master and a Fokker‐Planck equation are then derived for the phase‐space distribution of the macromolecule. In the Fokker‐Planck equation, all the information about the interaction among the beads of the macromolecule as well as the effects of the surrounding solvent is described by friction tensors, which are expressed in terms of the bead‐solvent interaction and the dynamic structure factor of the solvent. To explore the influence of the bead‐solvent potential on the dynamics of macromolecules, the friction tensors are calculated for a dumbbell molecule and for three choices of the interaction (Yukawa, Born‐Mayer, and Lennard‐Jones). Expressions are derived, in particular, for the friction tensor coefficients of the center‐of‐mass and the relative coordinates of the dumbbell. For the long‐term behaviour of the internal momentum autocorrelation function, moreover, an “algebraic decay” is found, in contrast to the (unphysical) exponential decay as known from phenomenological theory.

Yukawa, Born‐Mayer and Lennard‐Jones bead‐solvent interaction potentials.

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Yukawa, Born‐Mayer and Lennard‐Jones bead‐solvent interaction potentials.
Effect of the Linking Structure of Nonlinear Optical Side Groups on the Phase Behavior of an Aromatic Polyester Backbone
Authors: Lee Maeng‐Eun , Seong Seayeal , No Kyoung‐Tai , Kwon O‐Pil , Lee Suck‐Hyun
Published: March 2004

Summary: The phase behavior of poly(p‐phenylene terephthalate)s (PPT) with pendant side groups, N‐(4‐nitrophenyl)ethylaminoethanol (NPE) and N‐(4‐nitrophenyl)‐L‐prolinol (NPP) has been studied by using differential scanning calorimetry (DSC), wide‐angle X‐ray scattering (WAXS), and second harmonic generation (SHG). PPT‐NPE showed a layered liquid crystalline morphology while PPT‐NPP showed a completely amorphous structure. Compressive or shear stress applied on the polymer melt surface at 210 °C induced a more prominent layered structure of PPT‐NPE whereas the amorphous structure of PPT‐NPP remained unchanged under the stress. In order to understand this phase difference in terms of the repeat structure, we attempted theoretical ab initio Hartree‐Fock, and DFT calculations for the monomers and molecular dynamics for the bulk state. The results indicated that molecular configurations are a good way of microscopically understanding the phases of rigid backbone polymers with functional side groups: The NPT (constant particle number, pressure, and temperature) simulation data at 210 °C agree qualitatively with the experimental data and the difference between PPT‐NPE and PPT‐NPP could be understood using rotational energy barrier, steric hindrance and inter‐chain interactions. X‐ray diffractometer (XRD) simulation patterns for the oligomers are also in qualitative agreement with the experimental WAXS data and the structural parameters of stacks of PPT‐NPE chains are estimated to be layer distance (4.6 Å), backbone distance (21.5 Å), and side distance (12 Å).

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Structural Changes in Block Copolymer Solutions under Shear Flow as Determined by Non‐Equilibrium Molecular Dynamics
Authors: Rychkov Igor , Yoshikawa Kenichi
Published: March 2004

Summary: A non‐equilibrium molecular dynamics computer simulation on microsegregated solutions of symmetrical diblock copolymers is reported. As the polymer concentration increases, the system undergoes phase transitions in the following order: body centered cubic (BCC) micelles, hexagonal (HEX) cylinders, gyroid (GYR) bicontinuous networks and lamellae (L), which are the same morphology reported for block copolymer melts. Structural classification is based on the patterns of the anisotropic static structure factor and characteristic 3‐dimensional images. The systems in the BCC micellar (ρσ3 = 0.3) and HEX cylindrical (ρσ3 = 0.4) phases were then subjected to a steady planar shear flow. In weak shear flow, the segregated domains in both systems tend to rearrange into sliding parallel close‐packed layers with their normal in the direction of the shear gradient. At higher shear rates, both systems adopt a perpendicular lamellar structure with the normal along the neutral direction. A further increase in the shear rate results in a decrease in lamellar spacing without any further structural transitions. Two critical shear rate values that correspond to the demarcation of different structural behaviors were found.

Shear‐induced BCC‐LAM phase transition.

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Shear‐induced BCC‐LAM phase transition.
Effects of Reversible Chemical Reaction on Morphology and Domain Growth of Phase Separating Binary Mixtures with Viscosity Difference
Authors: Huo Yanli , Zhang Hongdong , Yang Yuliang
Published: March 2004

Summary: The effects of a reversible chemical reaction on morphology and dynamics of phase separating binary mixtures with viscosity difference are studied by numerically solving modified time‐dependent Ginzburg‐Landau and Navier‐Stokes equations. Much more interesting morphologies are observed in the system due to the coupling of reversible chemical reaction and viscosity difference between two components. When the chemical reaction rate is relatively low, the impact of viscosity difference on morphologies is prominent, so that the resulting patterns are affected by both reversible chemical reaction and viscosity difference. However, increasing the chemical reaction rate weakens the impact of viscosity difference on morphologies. Similarly, increasing the chemical reaction rate also suppresses the effects of viscosity difference on domain growth dynamics, which is prominent at the early stage of phase separation when the chemical reaction rate is relatively low. For both cases with relatively low and high chemical reaction rates, the average domain size eventually attains an equilibrium value due to the competition between the mixing of reversible chemical reaction and demixing of phase separation.

Domain patterns of a critical system with ϕini = 0, and Γ1 = Γ2 = 0.001.

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Domain patterns of a critical system with ϕini = 0, and Γ1 = Γ2 = 0.001.
Orientation of Polymer Chains in Dilute Solution under Shear: Effect of Chain Model and Excluded Volume
Authors: Hernández Cifre José G. , García de la Torre José
Published: March 2004

Summary: Polymer orientation in dilute solutions undergoing shear flow is investigated computationally by means of the Brownian dynamics simulation technique applied to the bead‐spring chain model. The dependence of the degree of orientation on the shear intensity is evaluated through a quantity called orientation resistance. All simulations were performed using non‐preaveraged hydrodynamic interaction (HI). The spring type (Gaussian or FENE) is shown to strongly determine the shear flow behavior of the chain orientation. Solvent quality (Θ, good or bad), represented by a suitable Lennard‐Jones intramolecular potential, does not affect the flow behavior but influences the values of the orientation resistance. Hence, the orientability of the polymer molecule is, in a way, related to the flow intensity.

Evolution of mG (orientational resistance parameter, open circles are simulation, dashed line is Gaussian approximation) and mτ (filled circles are simulation, dotted line is Gaussian approximation) with β for ideal Gaussian chains with N = 15.

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Evolution of mG (orientational resistance parameter, open circles are simulation, dashed line is Gaussian approximation) and mτ (filled circles are simulation, dotted line is Gaussian approximation) with β for ideal Gaussian chains with N = 15.
Crosslinking Kinetics: Partitioning According to Number of Crosslinks
Authors: Li Rujun , McCoy Benjamin J.
Published: March 2004

Summary: To mathematically describe crosslinking kinetics for polymers, we have proposed a novel method that accounts for the number of crosslinks, that is, partitioning according to number of crosslinks (PANC). By contrast, the well‐known method of numerical fractionation tracks generations of crosslinked molecules, defined to include a range of crosslinks. The proposed crosslinking kinetics yield a population balance model that provides moments and hence measurable average properties such as number average molecular weight and weight average molecular weight, polydispersity and average crosslink number. The gel points for batch and continuous‐flow stirred‐tank reactors are derived. Because the usual closure methods do not yield satisfactory convergence, new representations for post‐gelation moments are proposed. The results realistically show how the moments change with time in the post‐gel region.

The average number of crosslinks in the bulk and sol versus time in a batch reactor; the gel point is the dashed line.

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The average number of crosslinks in the bulk and sol versus time in a batch reactor; the gel point is the dashed line.
Monte Carlo Simulations of Copolymer Adsorption at Planar Chemically Patterned Surfaces: Effect of Interfacial Interaction
Authors: Semler James J. , Genzer Jan
Published: March 2004

Summary: Monte Carlo simulation utilizing the bond fluctuation model in conjunction with single and configurational biased Monte Carlo moves is used to study the adsorption of diblock (A‐block‐B) and alternating (A‐alt‐B) copolymers at flat, chemically heterogeneous surfaces comprising C and D domains. The main objective of this work is to address the effect of the strength of attraction between the adsorbing surface domains, D, and the copolymer adsorbing segments, B, on the copolymer's ability to recognize the chemical pattern on the surface. The results of our simulations reveal that both block and alternating copolymers have the ability to recognize the surface motif and transcribe it into the bulk material. The extent to which diblock copolymers transfer the chemical pattern from the surface to the bulk is relatively unaffected when the attractive B‐D potential is increased beyond a certain critical value. This behavior stems from the brush‐like conformation adopted by the diblock copolymer at the substrate. In contrast to the diblock copolymer, the adsorption of the alternating copolymer is influenced by the strength of the attraction between the copolymer's adsorbing segments and the adsorbing domains on the surface. Since the B segments are distributed evenly along the backbone, the alternating copolymers are more likely to adopt conformations in which the whole chain is “zipped” to the surface. The resultant entropic frustration is then alleviated through an increased formation of loops with little change to their length. Such conformational changes endow the alternating copolymer with the ability to invert the substrate pattern as the distance away from the surface is increased.

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Identification of the boundary surface of an interstellar cloud from a measurement of the photon far‐field
Authors: Belleni‐Morante A. , Mugelli F.
Published: March 2004

We study an inverse problem for photon transport in a host medium (e.g. an interstellar cloud), that occupies a bounded and strictly convex region Ω⊂R3. Under the assumption that the cross‐sections and the sources are known, we identify the boundary surface ∑ = ∂Ω(within a suitable family F of surfaces), provided that one value of the photon number density is measured at some given location far from Ω. Copyright © 2004 John Wiley & Sons, Ltd.
A characterization theorem for the evolution semigroup generated by the sum of two unbounded operators
Authors: Frosali Giovanni , van der Mee Cornelis V. M. , Mugelli Francesco
Published: March 2004

We consider a class of abstract evolution problems characterized by the sum of two unbounded linear operators A and B, where A is assumed to generate a positive semigroup of contractions on an L1‐space and B is positive. We study the relations between the semigroup generator G and the operator A+B. A characterization theorem for $G=\overline{A + B}$ is stated. The results are based on the spectral analysis of B(λ‐A)‐1. The main point is to study the conditions under which the value 1 belongs to the resolvent set, the continuous spectrum, or the residual spectrum of B(λ‐A) ‐1.

Applications to the runaway problem in the kinetic theory of particle swarms and to the fragmentation problem describing polymer degradation are discussed in the light of the previous theory. Copyright © 2004 John Wiley & Sons, Ltd.
Existence and uniqueness results for the continuous coagulation and fragmentation equation
Authors: Lamb Wilson
Published: March 2004

A non‐linear integro‐differential equation modelling coagulation and fragmentation is investigated using the theory of strongly continuous semigroups of operators. Under the assumptions that the coagulation kernel is bounded and the overall rate of fragmentation satisfies a linear growth condition, global existence and uniqueness of mass‐conserving solutions are established. This extends similar results obtained in earlier investigations. In the case of pure fragmentation, when no coagulation occurs, a precise characterization of the generator of the associated semigroup is also obtained by using perturbation results for substochastic semigroups due to Banasiak (Taiwanese J. Math. 2001; 5: 169–191) and Voigt (Transport Theory Statist. Phys. 1987; 16: 453–466). Copyright © 2004 John Wiley & Sons, Ltd.
On the convex compactness property for the strong operator topology and related topics
Authors: Mokhtar‐Kharroubi Mustapha
Published: March 2004

We give direct proofs of the convex compactness property for the strong operator topology in Lebesgue spaces for compact or weakly compact operators. We also show how this tool applies to spectral theory of perturbed semigroups. Some non‐weakly compact operators arising in perturbation theory of neutron transport are shown to be Dunford–Pettis operators. Copyright © 2004 John Wiley & Sons, Ltd.
Chaos for some infinite‐dimensional dynamical systems
Authors: Rudnicki Ryszard
Published: March 2004

This paper is devoted to the problem of chaotic behaviour of infinite‐dimensional dynamical systems. We give a survey of different approaches to study of chaotic behaviour of dynamical systems. We mainly discuss the ergodic‐theoretical approach to chaos which bases on the existence of invariant measures having strong analytic and mixing properties. This method is applied to study chaotic behaviour of semiflows generated by semilinear partial differential equations and linear transformations. Copyright © 2004 John Wiley & Sons, Ltd.
Two‐machine flow shop no‐wait scheduling with a nonavailability interval
Authors: Kubzin Mikhail A. , Strusevich Vitaly A.
Published: March 2004

We study a two‐machine flow shop scheduling problem with no‐wait in process, in which one of the machines is not available during a specified time interval. We consider three scenarios of handing the operation affected by the nonavailability interval. Its processing may (i) start from scratch after the interval, or (ii) be resumed from the point of interruption, or (iii) be partially restarted after the interval. The objective is to minimize the makespan. We present an approximation algorithm that for all these scenarios delivers a worst‐case ratio of 3/2. For the second scenario, we offer a 4/3‐approximation algorithm. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
An adaptive forecasting algorithm and inventory policy for products with short life cycles
Authors: Zhu Kaijie , Thonemann Ulrich W.
Published: March 2004

Products with short life cycles are becoming increasingly common in many industries, such as the personal computer (PC) and mobile phone industries. Traditional forecasting methods and inventory policies can be inappropriate for forecasting demand and managing inventory for a product with a short life cycle because they usually do not take into account the characteristics of the product life cycle. This can result in inaccurate forecasts, high inventory cost, and low service levels. Besides, many forecasting methods require a significant demand history, which is available only after the product has been sold for some time. In this paper, we present an adaptive forecasting algorithm with two characteristics. First, it uses structural knowledge on the product life cycle to model the demand. Second, it combines knowledge on the demand that is available prior to the launch of the product with actual demand data that become available after the introduction of the product to generate and update demand forecasts. Based on the forecasting algorithm, we develop an optimal inventory policy. Since the optimal inventory policy is computationally expensive, we propose three heuristics and show in a numerical study that one of the heuristics generates near‐optimal solutions. The evaluation of our approach is based on demand data from a leading PC manufacturer in the United States, where the forecasting algorithm has been implemented. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Lot streaming with supplier–manufacturer coordination
Authors: Li Chung‐Lun , Xiao Wen‐Qiang
Published: March 2004

Lot splitting refers to breaking a production lot into smaller sublots during production. Coordinating lot splitting decisions across multiple stages of a production process is a challenging task. Traditional lot splitting and lot streaming models implicitly assume that the entire system is operated and owned by the same firm, or there exists a coordinator who controls the operation of all machines in the system. In this paper, we consider the situation where the machines in a multiple‐stage production process are owned and managed by different companies. Every item in a given production lot has to go through the processing by the supplier's machine, followed by the manufacturer's machine, and so on. We develop and analyze coordination mechanisms that enable different parties in the supply chain to coordinate their lot splitting decisions so as to achieve a systemwide optimum. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
A general approach to the shape of failure rate and MRL functions
Authors: Mi Jie
Published: March 2004

Failure rate and mean residual life are two important characteristics for studying reliability of products. In literature, some work studied the shape of failure rate function based on the knowledge of the associated probability density function; some other work investigated the shape of mean residual life function based on the shape of the associated failure rate function separately for continuous case and discrete case. In this article, a general approach is developed which can be applied to the aforementioned studies. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Dichotomous categorical variable formation in mathematical programming discriminant analysis models
Authors: Glen J. J.
Published: March 2004

Classification models, whether generated by statistical techniques or mathematical programming (MP) discriminant analysis methods, are often simplified by ad hoc formation of dichotomous categorical variables from the original variables with, for example, a dichotomous variable taking value 1 if the original variable is above a threshold level and 0 otherwise. In this paper an MP discriminant analysis method is developed for forming dichotomous categorical variables in problems with discriminant functions that are monotone in the original variables. For each of the original variables from which dichotomous variables may be formed, a set of possible threshold levels for dichotomous variable formation is defined. An MP model is then used to determine both the threshold level for forming each dichotomous variable and the associated discriminant function coefficient. The proposed MP approach is applied to a published problem and a number of simulated problem sets. It is shown that the discriminant functions in dichotomous categorical variables generated by this new MP approach can in some cases outperform the functions generated by standard MP discriminant analysis models using the original variables. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Higher‐order Markov chain models for categorical data sequences*
Authors: Ching Wai Ki , Fung Eric S. , Ng Michael K.
Published: March 2004

In this paper we study higher‐order Markov chain models for analyzing categorical data sequences. We propose an efficient estimation method for the model parameters. Data sequences such as DNA and sales demand are used to illustrate the predicting power of our proposed models. In particular, we apply the developed higher‐order Markov chain model to the server logs data. The objective here is to model the users' behavior in accessing information and to predict their behavior in the future. Our tests are based on a realistic web log and our model shows an improvement in prediction. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Scurvy in adults and youngsters: the Dutch experience. A review of the history and pathology of a disregarded disease
Authors: Maat G. J. R.
Published: March 2004

Prior to the Dutch maritime expansion of the 17th and 18th centuries, scurvy was known in the Low Countries as an endemic disease. From the end of the 16th century the disease started to draw much more attention due to increasing long sea journeys of sailors. Already in the Dutch medical literature of the 16th century, a strong relation was expressed between the prolonged taking of foodstuffs of poor quality and the risk of contracting scurvy. Although from that time, many Dutch physicians recommended oranges, scurvy grass and brook‐lime, it took 200 years before inadequate therapy on the fleet was replaced by systematic prevention. Why did the old time effective recommendations for the therapy of scurvy stay inadequate for mariners? To understand, maritime and medical history were unfolded and evaluated with respect to palaeopathological findings reported for 39 cases of active scurvy and one case of healed scurvy.

The palaeopathology of scurvy in adults and still growing youngsters was investigated from the remains of 50 Dutch whalers who had been buried during the 17th and 18th centuries on an island of the Spitsbergen Archipelago. Conforming the clinical literature, the original haematomas from scurvy were found as a black staining at the tips of dental roots. In the weight‐bearing bones of the lower extremities large black stains were positioned bilaterally around endofractures of the metaphyses, bilaterally on joint surfaces and bilaterally at epiphyseal discs of youngsters. In the non‐weight‐bearing bones they were often found unilaterally, such as at insertions of muscles. Immunoenzymatic staining of microscopic sections proved that the black stains were from remnants of denatured haemoglobin. No microscopic bone repair activities had happened. In a case of healed scurvy it could even be demonstrated how many times the recovery process had taken place from the layers of appositional bone which had replaced the original subperiosteal haematomas. Copyright © 2004 John Wiley & Sons, Ltd.
Endocranial lesions in non‐adult skeletons: understanding their aetiology
Authors: Lewis M. E.
Published: March 2004

Reactive new bone on the endocranial surface of the skull in non‐adults has recently received a lot of attention in the palaeopathological literature. These features appear as layers of new bone on the original cortical surface, expanding around meningeal vessels, as isolated plaques, ‘hair‐on‐end’ extensions of the diploë or, as ‘capillary’ impressions extending into the inner lamina of the cranium. These lesions are commonly found on the occipital bone, outlining the cruciate eminence, but have also been recorded on the parietal and frontal bones, and appear to follow the areas of venous drainage. Although recognized as resulting from haemorrhage or inflammation, their precise aetiology is still a matter of controversy. This paper outlines their possible causes and examines their nature and distribution in a group of non‐adults from four archaeological sites in England. It is recommended that, when recording these lesions in the future, additional skeletal pathologies, the age of the child, and nature and distribution of the lesions also be taken into account. Copyright © 2004 John Wiley & Sons, Ltd.
A dystocic childbirth in the Spanish Bronze Age
Authors: Malgosa A. , Alesan A. , Safont S. , Ballbé M. , Ayala M. M.
Published: March 2004

Prehistoric cases of maternal and fetal death during labour are difficult to document. However, this must have been a frequent cause of death among young women who lived in hard circumstances and precarious health conditions. In this paper, a case of a Bronze Age woman who probably died during childbirth due to unavoidable reasons is presented: her baby was lying transversely with the right fetal arm protracted. Death of both mother and child was inevitable. Copyright © 2004 John Wiley & Sons, Ltd.
Dia Shoma (Mali), a medieval cemetery in the inner Niger delta
Authors: Zeitoun V. , Gatto E. , Rougier H. , Sidibé S.
Published: March 2004

The aim of this paper is to compare burial typology from Dia Shoma medieval cemetery (Mali) with previously documented funerary practices of the inner Niger delta in order to expand our knowledge of the mortuary rituals once practised in this region. Considering archaeological resources from an anthropological viewpoint provides us with new information about human migration, settlement, cultural affiliation and way of life. From this point of view, especially for the period between 800 and 1000 AD, Dia Shoma offers much insight into the history of this cultural melting pot. Dia Shoma is of particular interest in regards to migration in the Western Sahara region. The burials of Dia Shoma have been characterized by morphometrical features as well as associated funeral practices. The different types of burials that coexist at Dia Shoma indicate a region of cultural diversity. Along with the existence of different kinds of tombs, an increase in various archaeological remains lends evidence towards a community co‐occupied by herders, fishermen and farmers. The change in the association of funerary practices around 1000 AD could be interpreted as an indirect disturbance to the former socio‐economic trade and cultural exchange, possibly triggered by the fall of the Empire of Ghana under the influence of the Almoravides. Copyright © 2004 John Wiley & Sons, Ltd.
Bridging the gap between forensic anthropology and osteoarchaeology—a case of vascular pathology
Authors: Pinheiro J. , Cunha E. , Cordeiro C. , Vieira D. Nuno
Published: March 2004

We report on two cases of similar bony lesions and emphasize the importance of cooperative work between forensic anthropology and forensic pathology. A fairly well preserved cadaver of an old woman was autopsied by a forensic team at the National Institute of Forensic Medicine in Portugal. Although age at death and sex were easily determined, there was insufficient other evidence for personal identification. However, the female revealed severe and extensive lesions in both lower legs and these were useful for determining personal identity.

Here we describe the pathological findings, consistent with venous chronic insufficiency. The woman's family subsequently confirmed she suffered from this condition. Furthermore, they informed us of varicose ulcers, which also were suspected by the ties found, in both her legs, during autopsy. A long history of venous chronic insufficiency was subsequently found in her medical records.

We compare these forensic findings to the bony pathologies of a male skeleton from the Coimbra Identified Skeletal Collection not previously diagnosed.

We argue that these two cases represent the same pathological condition. Without the medical forensic work, the skeletal remains of the second case might not have been positively identified. The benefits of cooperative work between medical and anthropological forensic specialists are reinforced leading to resolution of otherwise unidentified skeletal pathological conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Del(18p) syndrome with increased nuchal translucency in prenatal diagnosis
Authors: Kim Young‐Mi , Cho Eun‐Hee , Kim Jin‐Mi , Lee Moon‐Hee , Park So‐Yeon , Ryu Hyun‐Mee
Published: March 2004

We report a de novo translocation between chromosome 15 and 18 resulting in monosomy 18p in prenatal diagnosis. The patient was referred for amniocentesis due to increased nuchal translucency (INT) (5 mm) at 13.6 weeks of gestation. Karyotype of the fetus revealed 45,XX,der(15;18)(q10;q10) in all metaphases. The targeted fetal ultrasound at 20 weeks of gestation did not show any special physical abnormalities other than 6.4 mm of nuchal fold thickness. Molecular cytogenetic findings using CGH and FISH confirmed the del(18p) with dicentromeres from both chromosome 15 and 18. The present study shows that the INT at first trimester was the only prenatal finding for the fetus with del(18p) syndrome and that molecular cytogenetic methods are useful for detecting chromosomal aberrations precisely. Copyright © 2004 John Wiley & Sons, Ltd.
Maternal serum and amniotic fluid levels of macrophage inhibitory cytokine 1 in Down syndrome and chromosomally normal pregnancies
Authors: Wallace Euan M. , Marjono Budi , Brown David A. , Crossley Jennifer , Tong Stephen , Aitken David , Breit Sam
Published: March 2004

Objectives

To measure maternal serum and amniotic fluid levels of macrophage inhibitory cytokine‐1 (MIC‐1) in Down syndrome and normal pregnancies, assessing the utility of MIC‐1 as a prenatal marker of Down syndrome.

Methods

Stored serum from 64 Down syndrome and 399 control pregnancies, collected at 8 to 17 weeks of pregnancy, and stored amniotic fluid from 17 Down syndrome and 53 controls, collected at 15 to 19 weeks of pregnancy, were retrieved for analysis. MIC‐1 was measured using an established in‐house ELISA, blinded to sample type.

Results

In maternal serum, MIC‐1 levels are not altered in Down syndrome in either the first or second trimester. Levels, expressed as median (95% CI) multiples of the median (MoM), in the Down syndrome cases and controls were 1.07 (0.9–1.1) MoM and 1.0 (0.95–1.03) MoM respectively. In amniotic fluid, MIC‐1 levels were significantly decreased compared to controls, 0.52 (0.44–0.64) MoM versus 1.0 (0.85–1.08) MoM (p < 0.0001).

Conclusion

MIC‐1 is decreased in amniotic fluid but not in maternal serum in Down syndrome pregnancies. MIC‐1 will not be useful as a prenatal marker of Down syndrome. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of correcting for smoking status when screening for chromosomal anomalies using maternal serum biochemistry and fetal nuchal translucency thickness in the first trimester of pregnancy
Authors: Spencer Kevin , Bindra Renu , Cacho Anna Maria , Nicolaides Kypros H.
Published: March 2004

Objectives

To evaluate the influence of cigarette smoking status on maternal serum free β‐hCG, PAPP‐A and fetal nuchal translucency (NT) thickness at 11 to 14 weeks of gestation in a large cohort of women screened prospectively for chromosomal anomalies.

Methods

Information on maternal cigarette smoking status, maternal age, maternal serum biochemical marker levels and fetal NT were collected from the prenatal screening computer records in two OSCAR screening centres. Data was available from 32 730 unaffected pregnancies and from 124 with Down syndrome. Statistical analysis of the marker levels in the smoking and non‐smoking group were carried out. The impact on false‐positive rate of correcting for smoking status was assessed from a modelling exercise.

Results

Prevalence of smoking was significantly affected by maternal age with an overall incidence of 11.5%, which varied from 35% in women under 20 to 7% in women over 35. In the unaffected population, the median free β‐hCG MoM was significantly lower in the smoking group (0.97 vs 1.00) as was that for PAPP‐A (0.84 vs 1.02). The standard deviation of the log10 MoM free β‐hCG was lower in the smoking group and that for PAPP‐A was higher in the smoking group. The difference in median marker levels did not seem to be related to the number of cigarettes smoked per day. In the group with Down syndrome, the median MoM free β‐hCG was not significantly different in the smokers (1.69 vs 1.86) as was that for PAPP‐A (0.53 vs 0.57). Fetal delta NT was not significantly different in the unaffected smokers (0.11 vs 0.0 mm) or in those with Down syndrome (1.96 vs 2.25 mm). In the smoking group, when screening using maternal serum biochemistry and age alone, the false‐positive rate was 6.17%, compared to 4.67% in an age‐matched group of non‐smokers. Correcting for smoking status by dividing the measured MoM by the median found in the smoking group resulted in the false‐positive rate falling to 4.40%. When screening using NT, maternal serum biochemistry and age, the false‐positive rate in smokers was 4.48%, which reduced to 3.46% after correction—in line with the 3.76% in the non‐smoking group. The impact on detection rate was too small to be accurately measured.

Conclusions

The impact of smoking on first‐trimester biochemical marker levels does not seem to be dose related. Whilst correcting first‐trimester biochemical markers for maternal smoking status has little impact at the population level for detection rates, a considerable reduction in false‐positive rate can be achieved, reducing the level to that seen in non‐smokers. However, the effect on the individual patient‐specific risk can be substantial and could certainly make a difference to the patient's decision on whether to have an invasive test. Copyright © 2004 John Wiley & Sons, Ltd.
The three‐vessel and tracheal view of the fetal heart: an in utero sonographic evaluation
Authors: Zalel Yaron , Wiener Yifat , Gamzu Ronni , Herman Arie , Schiff Eyal , Achiron Reuven
Published: March 2004

Objectives

To establish a nomogram for fetal cardiac three‐vessel view diameter changes during gestation.

Methods

The study is a prospective cross‐sectional evaluation of 338 male and female fetuses between 14 and 38 weeks of normal singleton pregnancies. Measurements of fetal pulmonary artery, aorta and superior vena cava diameters, performed on a transverse view of the upper mediastinum were conducted using transvaginal ultrasonography between 14 to 18 weeks and transabdominal after 19 weeks' gestation.

Results

Adequate measurements of the three cardiac vessels were obtained in 338 fetuses. The regression equations for vessel diameters modeled as function of gestational age were pulmonary artery diameter (mm) = −2.275 + 0.273 × gestational age (week), aorta diameter (mm) = −1.77 + 0.227 × gestational age (week), and SVC diameter (mm) = −0.98 + 0.142 × gestational age (week). The correlation coefficients between gestational age and the diameter of the vessels were, r = 0.93, r = 0.93 and r = 0.86 for pulmonary artery, aorta and SVC respectively (all found to be highly statistically significant, p < 0.0001). The normal mean and 90% prediction limits were defined.

Conclusion

Our data present the normal range of fetal heart three‐vessel diameters during gestation. They may allow intrauterine assessment of their development and an adjunct in the detection and evaluation of great vessel pathology. Copyright © 2004 John Wiley & Sons, Ltd.
The thick heterogeneous (jellylike) placenta: a strong predictor of adverse pregnancy outcome
Authors: Raio Luigi , Ghezzi Fabio , Cromi Antonella , Nelle Mathias , Dürig Peter , Schneider Henning
Published: March 2004

Objective

To present a series of cases with a sonographic thick and heterogeneous placenta, and to review the literature.

Methods

A series of 16 cases were analyzed. A heterogeneous placenta was defined as a thick placenta with a patchy decrease of echogenicity, which quivered like jelly to sharp abdominal pressure. A comprehensive morphologic and Doppler evaluation of the fetus and the uteroplacental circulation was performed. The pregnancy course and the neonatal outcome of the present series and of those reported in the literature were reviewed.

Results

Placental thickness was greater than the 95th centile in all cases. The placenta was located laterally in 13 (81.3%) cases. Twelve women delivered earlier than 34 weeks either spontaneously or because of deteriorating maternal and/or fetal conditions (n = 10). Perinatal death occurred in eight cases. The uterine artery Doppler and the umbilical artery were abnormal in eight and eight cases respectively. A discordancy between the umbilical artery size was present in six cases. Abruptio placentae occurred in three cases. A strong association between hypertensive disorders and fetal growth restriction was found in our series and in literature.

Conclusions

The sonographic presence of thick heterogeneous placenta is strongly associated with an adverse pregnancy outcome and often with perinatal death. Copyright © 2004 John Wiley & Sons, Ltd.
Favourable outcome of a tight constriction band secondary to amniotic band syndrome
Authors: Sentilhes L. , Verspyck E. , Eurin D. , Ickowicz V. , Patrier S. , Lechevallier J. , Marpeau L.
Published: March 2004

Amniotic band syndrome or amniotic disruption complex is a well‐known congenital limb abnormality, which occurs in 1 in 1200 to 1 in 15 000 live births. In cases of an isolated band constriction, it has been speculated that the bands lead to decreased blood flow in the constricted limb and subsequent natural amputation. Fetal surgery could be considered in these situations in order to release the constriction band in threatened limb amputation. We present a case of a tight constriction ring secondary to amniotic band syndrome with a favourable outcome, despite the failure of an attempted surgical procedure. Copyright © 2004 John Wiley & Sons, Ltd.
Prenatal diagnosis and management of sex chromosome aneuploidy: a report on 98 cases
Authors: Brun Jean‐Luc , Gangbo Flore , Qi Wen Zon , Galant Katia , Taine Laurence , Maugey‐Laulom Brigitte , Roux Denis , Mangione Raphaelle , Horovitz Jacques , Saura Robert
Published: March 2004

Objectives

To analyse the management of pregnancy after prenatal diagnosis of sex chromosome aneuploidy (SCA) and the factors influencing genetic counselling and parental decision.

Methods

Between 1991 and 2001, 73 non‐mosaic fetal SCA were diagnosed in our centre and 25 were referred to us from outside institutions. The same geneticist carried out genetic counselling. The outcome of pregnancies and the termination trend over time were determined according to the type of SCA. Clinical parental data were analysed in order to assess whether they influenced genetic counselling.

Results

45,X was diagnosed in 41 fetuses. The main indication for karyotyping was abnormal ultrasound (83%). The termination rate was 93%. Sex chromosome polysomies (SCP) including 47,XXY, 47,XXX, and 47,XYY were diagnosed in 31, 16, and 10 fetuses respectively. The main indication for karyotyping was advanced maternal age (60%). The termination rate was 32, 25, and 20% respectively. The difference between the termination rate for local cases (25%) and referred cases (33%) was not significant. The termination rate for pregnancies with SCP was 38% in 1991 to 1994, 34% in 1995 to 1998, and 12% in 1999 to 2001. The parents' characteristics did not influence the outcome of pregnancy.

Conclusions

The relatively low termination rate (28%) in pregnancies where the fetus was affected by SCP and the decreasing termination trend over time in our centre suggest an improved knowledge of the pathological conditions associated with SCP, influencing genetic counselling. Copyright © 2004 John Wiley & Sons, Ltd.
Sialic acid–deficient invasive trophoblast antigen (sd‐ITA): a new urinary variant for gestational Down syndrome screening
Authors: Sutton Jaime M. , Cole Laurence A.
Published: March 2004

Background

Invasive trophoblast antigen (ITA), also known as hyperglycosylated hCG, is a glycosylation variant of hCG produced by invasive cytotrophoblast cells. Publications show that ITA is potentially a sensitive test for Down syndrome screening, reportedly detecting 38 and 80% of cases at a 5% false‐positive rate in the first and second trimesters of pregnancy respectively. ITA has six oligosaccharides varying greatly in terminal sialic acid content (0–19 residues), leading to wide‐charge heterogeneity. With the objective of developing an improved Down syndrome screening test, we examined the charge, or sialic acid variants, of ITA.

Methods

Twenty urine samples were collected from the 16th to 18th week of gestation from 10 patients with trisomy 21 fetuses, demonstrated by karyotype analysis, and from 10 patients with normal karyotype pregnancies. Proteins in each sample were separated by preparative isoelectric focusing. Fractions were collected, pooled into the pl ranges of 3.0 to 4.0, 4.1 to 5.0, 5.1 to 6.0 and 6.1 to 7.0 and assayed for ITA.

Results

A difference in the distribution of ITA charge variants was demonstrated between cases and controls, most apparent in the less acidic (pl 5.1–7.0) range. The controls and Down syndrome samples contained 26.7 ± 14% versus 45.6 ± 20%, respectively, of the less acidic form of ITA (P = 0.02).

Conclusions

The ITA in Down syndrome cases is composed of a much higher proportion of less acidic ITA. This could be the major source of elevated levels of ITA in Down syndrome pregnancies. It is postulated that the development of a new assay specifically measuring ITA that is deficient in sialic acid might enhance the utility of the already highly sensitive screening tests for Down syndrome. Copyright © 2004 John Wiley & Sons, Ltd.
Two unusual chromosome aberrations ascertained by sonographic anomalies
Authors: Bourthoumieu Sylvie , Esclaire Francoise , Terro Faraj , Fiorenza Maryse , Eyraud Jean‐Luc , Servaud Michel , Cantaloube Muriel , Fermeaux Veronique , Yardin Catherine
Published: March 2004

We describe two cases of sonographic abnormalities associated with unusual chromosomal aberrations. Case 1 presented with a cystic hygroma at 12 weeks' gestation. Cytogenetic analysis revealed an unbalanced complex chromosome rearrangement implicating chromosomes 6, 13 and 21 (karyotype: 47,XX,t(6;21;14)(q14;q21;q21)mat,+21) and corresponding to a complete trisomy 21. This anomaly resulted from malsegregation of a maternal balanced three‐way translocation. For case 2, an alobar holoprosencephaly was identified by ultrasonography at 23 weeks' gestation. Chromosomal analysis showed a recombinant rec (13), dup q chromosome, secondary to unequal crossing‐over of a paternal pericentric inversion of chromosome 13, giving rise to partial trisomy 13q (karyotype: 46,XX,rec(13)dup(13q)inv(13)(p11q21)pat). These two cases illustrate the role of ultrasound in leading to detection not only of foetal chromosomal aberrations but also of rare balanced chromosomal rearrangements presented by one of the two parents. Copyright © 2004 John Wiley & Sons, Ltd.
Characteristics of “controversial” children: An exploration of teacher and parent social behavior rating scale datasets
Authors: Hill Diane K. , Merrell Kenneth W.
Published: March 2004

The term “controversial” has been used in the professional literature to describe children and adolescents who have the seemingly paradoxical quality of being both socially skilled and antisocial. Although there have been some widely influential studies regarding controversial children and youth, there has been relatively little research in this area, and the general construct is not well understood. This study addressed the lack of knowledge of characteristics of controversial children and youth through careful descriptive analysis of large, national norming samples from two social and antisocial behavior rating scales. Two experimental subscales were created to represent the characteristics associated with being controversial. Possible cutoff scores for each subscale were investigated to best reflect the criterion developed to represent the controversial construct, and the specific characteristics of the obtained samples were carefully analyzed. Results of this preliminary exploration indicated that (a) the percentage of children and adolescents who fit the characteristics of the controversial criterion are quite small, (b) two thirds of those identified as controversial were boys between the ages of 10 and 14, and (c) a greater number of girls were identified when data from home and community settings rather than school settings were analyzed. Implications of the results for future research and educational/clinical practice are discussed. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 497–507, 2004.
Self‐regulation empowerment program: A school‐based program to enhance self‐regulated and self‐motivated cycles of student learning
Authors: Cleary Timothy J. , Zimmerman Barry J.
Published: March 2004

This article describes a training program, Self‐Regulation Empowerment Program (SREP), that school professionals can use to empower adolescent students to engage in more positive, self‐motivating cycles of learning. It is a two‐part approach whereby self‐regulated learning coaches (SRC) (a) use microanalytic assessment procedures to assess students' self‐regulation beliefs and study strategies and (b) train students to use these strategies in a cyclical, self‐regulation feedback loop. Ultimately, students learn how to set goals, select and monitor strategy effectiveness, make strategic attributions, and adjust their goals and strategies. The program was developed from social‐cognitive theory and research and integrates many of the essential features of the problem‐solving model. Interventions used in the SREP include graphing, cognitive modeling, cognitive coaching, and structured practice sessions. A case study is presented to illustrate procedures for implementing the program. Implications for school psychologists and teachers also are presented and discussed. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 537–550, 2004.