bluuebunny/crossref_metadata_2025_split huggingface dataset:
First‐trimester diagnosis of conjoined twins
Authors: Pajkrt Eva , Jauniaux Eric 
Published: September 2005

AbstractConjoined twins are a rare and complex complication of monozygotic twinning, which is associated with high perinatal mortality. Early prenatal diagnosis of conjoined twins allows better counselling of the parents regarding the management options, including continuation of pregnancy with post‐natal surgery, termination of pregnancy or selective fetocide in case of a triplet pregnancy. With the introduction of high‐resolution and transvaginal ultrasound imaging, accurate prenatal diagnosis of conjoined twins is possible early in pregnancy. We have reviewed the medical literature on the early prenatal diagnosis of suspected conjoined twins using a MEDLINE search. Although first‐trimester diagnosis of conjoined twins is feasible, false‐positive cases are common before 10 weeks because, earlier in gestation, fetal movements are limited and monoamniotic twins may appear conjoined. As most parents opt for immediate termination of pregnancy at confirmation of the diagnosis, there are limited data on the prenatal follow‐up of conjoined twins. When the parents opt for conservative management, half of the fetuses die in utero and another 44% will die during the neonatal period. A detailed analysis of case reports where 3D imaging was used indicates that this modality does not improve on the diagnosis made by 2D ultrasound. Overall, very early prenatal diagnosis and first‐trimester 3D imaging provide very little additional practical medical information compared to the 11–14 weeks' ultrasound examination. Copyright © 2005 John Wiley & Sons, Ltd.
Conjoined twins
Authors: Spitz Lewis 
Published: September 2005

AbstractConjoined twins have been a source of fascination for both the general public and the medical profession since time immemorial. Their birth was initially viewed as an ominous sign of impending disaster. This was followed by a prolonged period through the Middle Ages and into the nineteenth century when they were regarded as freaks or monstrosities and were exhibited with substantial financial reward at circuses and sideshows. Recently, conjoined twins have attracted intense media interest, which has coincided with increasing success in their separation. This article gives an overview of the role of prenatal ultrasound in assessing the prognosis and discusses the post‐natal surgical management and outcome. Copyright © 2005 John Wiley & Sons, Ltd.
Acardiac anomaly: current issues in prenatal assessment and treatment
Authors: Wong Amy E. , Sepulveda Waldo 
Published: September 2005

AbstractAcardiac anomaly is a rare condition affecting monochorionic multiple pregnancies. We review this condition with emphasis on its prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, it is important to monitor the pump twin for signs of decompensation and, if indicated, intervene by interrupting vascular supply to the acardiac twin. The goal of treatment is to maximize the pump‐twin's chance of survival. To assist with the decision of when to treat, we suggest a new classification system based on prognostic factors, specifically the size and growth of the acardiac twin and the cardiovascular condition of the pump twin. When the acardiac twin is small and no signs of cardiovascular impairment in the pump twin are present, we suggest serial ultrasound surveillance to detect any worsening of the condition. In cases with a large acardiac twin or rapid growth of the acardiac mass, we recommend prompt intervention. Once treatment is indicated, the intrafetal approach to interrupt the vascular supply to the acardiac twin appears to be superior to cord occlusion techniques as it is simpler, safer and more effective. The first line of treatment, if available, should be ultrasound‐guided laser coagulation or radiofrequency ablation of the intrafetal vessels. Copyright © 2005 John Wiley & Sons, Ltd.
Psychological aspects of prenatal diagnosis and its implications in multiple pregnancies
Authors: Bryan Elizabeth 
Published: September 2005

AbstractCouples expecting twins are often unrealistically optimistic and are therefore unprepared for the complications as well as the practical and emotional impact the birth of twins can have on the family. All such couples will need information and support throughout the pregnancy and beyond. In this review, the various aspects that should be addressed are discussed, in particular, health care workers and counsellors need to be aware of the stress experienced by parents who have been through prolonged treatment for infertility or who face the special problems associated with the loss of one twin (implies the loss could be other than death). Copyright © 2005 John Wiley & Sons, Ltd.
Management of fetofetal transfusion syndrome
Authors: Robyr R. , Quarello E. , Ville Y. 
Published: September 2005

AbstractFeto‐fetal transfusion syndrome contributes heavily to high rates of perinatal mortality and morbidity in monochorionic multiple pregnancies. Its prenatal management has been controversial for at least 25 years. We review the recent literature in order to present the basis for a pragmatic reappraisal of the management of this condition. Laser surgery of the chorionic plate inter‐twin anastomoses is the best first‐line treatment when the syndrome develops before 26 weeks' gestation. Survival (including quality of survival) and gestational age at delivery are improved when compared to serial amnioreduction. Second‐line treatment options include repeat‐laser, intra‐uterine blood transfusion, serial amnioreduction, selective feticide using bipolar cord coagulation or elective delivery, depending upon gestational age and the severity of the disease and its complications. We have found that fetoscopic placental surgery has proven itself over simplicity of amnioreduction. There is no evidence that treatment should be customized according to the stage of the disease at diagnosis. Early recognition of the syndrome through fortnightly serial ultrasound follow‐up of all monochorionic pregnancies should ensure timely referral and make up for geographical constraints. Laser surgery should now be available in fetal medicine units that are managing at least 20 cases per year. Copyright © 2005 John Wiley & Sons, Ltd.
Sonographic umbilical cord morphometry and coiling patterns in twin–twin transfusion syndrome
Authors: Cromi Antonella , Ghezzi Fabio , Dürig Peter , Di Naro Edoardo , Raio Luigi 
Published: September 2005

AbstractObjectiveMonochorionic twins with twin–twin transfusion syndrome (TTTS) provide an ideal model in which to evaluate the influence of differing hemodynamic stress on umbilical cord (UC) morphology. The purpose of this study was to investigate the UC morphometry and UC coiling pattern at ultrasound in monochorionic twin pregnancies with TTTS.MethodsA targeted sonographic evaluation of the UC was performed in 21 consecutive twin pregnancies with untreated TTTS. The cross‐sectional area of the UC and of its vessels was measured. The Wharton's jelly area was computed by subtracting the vessels area from the area of the UC. The umbilical coiling index (UCI) was calculated as the reciprocal of the sonographic length of one complete vascular coil. The UCs were classified as uncoiled, normally coiled, hypocoiled, hypercoiled and atypically coiled (UCI not valuable).ResultsThe UCs of recipient twins were invariably larger than those of donors, and this difference was mainly attributable to both a larger amount of Wharton's jelly and a larger umbilical vein diameter. The proportion of lean UCs was higher in the donor than in the recipient fetuses (18/21 vs 1/21, p < 0.0001), while large UCs were significantly more frequent in the recipient than in the donor twins (13/21 vs 1/21, p = 0.0002). In all twin pairs, a discordant umbilical coiling pattern was observed between the donor and the recipient twin. The prevalence of uncoiled and hypocoiled cords was higher in the donor group, while hypercoiling and atypical coiling were more frequently detected in the recipient group.ConclusionsA discordant UC morphometry represents an additional phenotypic feature of twins with TTTS. The discordant intertwin coiling pattern in TTTS argues against an exclusively genetic origin of UC twists, and further supports a key role of hemodynamic forces in coiling development. Copyright © 2005 John Wiley & Sons, Ltd.
Diagnosis of conjoined twins before 16 weeks' gestation: the 4‐year experience of one medical center
Authors: Maymon Ron , Mendelovic Sonia , Schachter Morey , Ron‐El Raphael , Weinraub Zwi , Herman Arie 
Published: September 2005

AbstractBackgroundDescriptions of the rarely occurring condition of conjoined twins are sparse.MethodsWe report a case series of four conjoined twin pregnancies diagnosed up to 16 weeks of gestation. One was in a quadruplet in vitro fertilization intracytoplasmic sperm injection (IVF‐ICSI) pregnancy of cryopreserved embryos and the others were spontaneous conceptions. Three were thoracopagus and had increased nuchal translucency (NT) or big nuchal cysts and one was omphalopagus.ResultsAll the three affected twin pregnancies were terminated by cervical dilatation and uterine evacuation. In another case, selective fetal reduction, shortly followed by embryo reduction to singleton was performed. Histological analysis of one case revealed dissimilar gender. No further cytogenetic or molecular studies were conducted by parental request. The pathophysiology of increased NT, subcutaneous edema or nuchal cysts in thoracopagus conjoined twins, the possible embryonic events that may lead to dizygotic conjoined twins and the clinical management of conjoined twins in sets of multiple gestation are discussed.ConclusionsThe current case series illustrates that there are many problems related to this rare, but intriguing, accident of nature that still need to be overcome. Copyright © 2005 John Wiley & Sons, Ltd.
An algorithm to derive a numerical daily dose from unstructured text dosage instructions
Authors: Shah Anoop D. , Martinez Carlos 
Published: September 2005

AbstractPurposeThe General Practice Research Database (GPRD) is a database of longitudinal patient records from general practices in the United Kingdom. It is an important data source for pharmacoepidemiology studies, but until now it has been tedious to calculate the daily dose and duration of exposure to drugs prescribed. This is because general practitioners routinely record dosage instructions as free text rather than in a structured way. The objective was to develop and assess the validity of an automated algorithm to derive the daily dose from text dosage instructions.MethodsA computer program was developed to derive numerical information from unstructured text dosage instructions. It was tested on dosage texts from a random sample of one million prescription entries. A random sample of 1000 of these converted texts were manually checked for their accuracy.ResultsOut of the sample of one million prescription entries, 74.5% had text containing the daily dose, 14.5% had text but did not include a quantitative daily dose statement and 11.0% had no text entered. Of the 1000 texts which were checked manually, 767 stated the daily dose. The program interpreted 758 (98.8%) of these correctly, produced errors in four cases and failed to extract the dose from five texts.ConclusionsAn automated algorithm has been developed which can accurately extract the daily dose from almost 99% of general practitioners' text dosage instructions. It increases the utility of GPRD and other prescription data sources by enabling researchers to estimate the duration of drug exposure more efficiently. Copyright © 2005 John Wiley & Sons, Ltd.
Optical and electrochemical properties of copoly(aryl ether)s consisting of alternate 2,5‐distyrylbenzene and electron‐transporting oxadiazole or triazole derivatives
Authors: Chen Shinn‐Horng , Chen Yun 
Published: September 2005

AbstractNew copoly(aryl ether) P1 consisting of alternate electron‐transporting 2‐(3‐(trifluoromethyl)phenyl)‐5‐(4‐(5‐(3‐(trifluoromethyl)phenyl)‐1,3,4‐oxadiazol‐2‐yl)‐2,5‐bis(hexyloxy)phenyl)‐1,3,4‐oxadiazole and hole‐transporting 2,5‐distyrylbenzene (DSB) was synthesized via nucleophilic substitution polymerization. We investigated the optical and electrochemical properties of alternate copoly(aryl ether)s P1–P6, which contain the same hole‐transporting DSB segments, but with different electron transporting segments. The effect of trifluoromethyl groups in electron transporting segments is also discussed. Referencing to the spectra of their model compounds M1–M4, the emissions of P1–P3 are dominated exclusively by the hole‐transporting fluorophores with longer emissive wavelength about 452–453 nm via efficient excitation energy transfer. Furthermore, P1–P3 also exhibit unique variations in energy transfer in acidic media and solvatochromism in organic solvents. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of P1–P4, estimated from electrochemical data, are −5.12, −5.15, −5.18, −5.00 eV and −2.93, −3.39, −3.49, −2.76 eV, respectively. The electron and hole affinity of P1–P6 can be enhanced simultaneously by introducing isolated hole‐ and electron‐transporting segments in backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5083–5096, 2005
Syntheses of graft and star copolymers possessing polyolefin branches by using polyolefin macromonomer
Authors: Kaneko Hideyuki , Kojoh Shin‐ichi , Kawahara Nobuo , Matsuo Shingo , Matsugi Tomoaki , Kashiwa Norio 
Published: September 2005

AbstractGraft and star copolymers having poly(methacrylate) backbone and ethylene–propylene random copolymer (EPR) branches were successfully synthesized by radical copolymerization of an EPR macromonomer with methyl methacrylate (MMA). EPR macromonomers were prepared by sequential functionalization of vinylidene chain‐end group in EPR via hydroalumination, oxidation, and esterification reactions. Their copolymerizations with MMA were carried out with monofunctional and tetrafunctional initiators by atom transfer radical polymerization (ATRP). Gel‐permeation chromatography and NMR analyses confirmed that poly(methyl methacrylate) (PMMA)‐g‐EPR graft copolymers and four‐arm (PMMA‐g‐EPR) star copolymers could be synthesized by controlling EPR contents in a range of 8.6–38.1 wt % and EPR branch numbers in a range of 1–14 branches. Transmission electron microscopy of these copolymers demonstrated well‐dispersed morphologies between PMMA and EPR, which could be controlled by the dispersion of both segments in the range between 10 nm and less than 1 nm. Moreover, the differentiated thermal properties of these copolymers were demonstrated by differential scanning calorimetry analysis. On the other hand, the copolymerization of EPR macromonomer with MMA by conventional free radical polymerization with 2,2′‐azobis(isobutyronitrile) also gave PMMA‐g‐EPR graft copolymers. However, their morphology and thermal property remarkably differed from those of the graft copolymers obtained by ATRP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5103–5118, 2005
A local‐probe analysis of the rheology of a "solid liquid"
Authors: Houston J. E. 
Published: September 2005

AbstractResults are shown demonstrating the application of the interfacial force microscope to a study of the micro‐scale mechanical properties of an extreme example of a viscoelastic material, one that is often referred to as a “solid liquid.” Experiments involve relaxation measurements taken over a range of deformations, to establish linearity, and scaled according to the optically determined contact radius. In addition, the data is Fourier analyzed to obtain the frequency response of both the real and imaginary components of the shear modulus. The results from such an analysis of a single 3 s measurement are shown to be in remarkable agreement with published results from a series of single‐frequency measurements using a classical rheometer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2993–2999, 2005
Morphology study of Nafion membranes prepared by solutions casting
Authors: Lin Hsiu‐Li , Yu T. Leon , Huang Cheng‐Hung , Lin Tsang‐Lang 
Published: September 2005

AbstractThe structures of Nafion membranes prepared by solutions casting from low aliphatic alcohols/water mixture solvents and N,N′‐dimethyl formamide (DMF) solvent were investigated using differential scanning calorimeter and small angle X‐ray scattering. The aggregation behavior of Nafion molecules in the casting solutions was also investigated using dynamic light scattering. We show that the morphology of membranes was strongly influenced by the conformations of Nafion molecules in the solutions. In aliphatic alcohol/water mixture solvents, which have a worse compatibility with Nafion backbones, the Nafion molecules aggregate and form fringed rod‐like structures. These primary rod‐like structures then aggregate again through fringed side chains to form secondary ionic aggregations. In DMF solvent, owing to its better compatibility with Nafion backbones, less Nafion molecules aggregate. The high degree of Nafion molecular aggregations in aliphatic alcohol/water mixture solvents leads to a high degree of hydrophobic and hydrophilic phase separation for membranes prepared by casting from Nafion/aliphatic alcohol/water solutions. However, the lower degree of molecular aggregations in DMF solvent results in a lower degree of hydrophobic and hydrophilic phase separation for membranes prepared by casting from Nafion/DMF solution. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3044–3057, 2005
Effects of ultrasonic oscillations on linear viscoelastic behaviors of metallocene‐catalyzed linear low density polyethylene and its blends with low density polyethylene
Authors: Wu Hong , Guo Shaoyun , Li Zhen 
Published: September 2005

AbstractThe effects of ultrasonic oscillations on linear viscoelastic behaviors of metallocene‐catalyzed linear low density polyethylene (mLLDPE) and its blends with low density polyethylene (LDPE) were investigated in this article. The experimental results showed that ultrasonic oscillations can increase the cross modulus, characteristic time, plateau modulus, complex viscosity, zero shear viscosity, and flow activation energy of mLLDPE. Molecular weight of mLLDPE increases but molecular polydispersity index decreases in the presence of ultrasonic oscillations. It has been found for mLLDPE/LDPE blends that the addition of LDPE as well as ultrasonic oscillations can decrease the cross modulus but increase the characteristic time of the blends. The complex viscosity, zero shear viscosity, and flow activation energy of the blends increase by the addition of LDPE, but decrease in the presence of ultrasonic oscillations. Shear thinning effect of the blends is improved because of the addition of LDPE. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3030–3043, 2005
Restoration of PSD from Chord Length Distribution Data using the Method of Projections onto Convex Sets
Authors: Worlitschek Jörg , Hocker Thomas , Mazzotti Marco 
Published: September 2005

AbstractThe interpretation of chord length distributions (CLDs) is essential in many fields and has been discussed by various authors. Here, the technique of the Focused Beam Reflectance Measurement (FBRM) is considered as on‐line and in‐situ measurement device of the CLD of particle dispersions and emulsions. Though useful in general, this measurement cannot be converted directly into a particle size distribution (PSD), unless the physics of the measurement method is described and accounted for. In this work we present a new tool to carry out such a conversion once the particle shape is known a priori and can be fixed, which is based on a two step procedure: (1) the computation of a matrix that converts the PSD of a population of particles with given shape into the corresponding CLD using a 3‐dimensional geometric model; (2) the calculation of the PSD from the resulting linear matrix equation for the measured CLD. Here, the method of Projections onto Convex Sets (POCS) is applied to solve the PSD restoration problem, which is a mathematically ill‐posed inverse problem. We study the effect of particle shape and matrix dimension on the ill‐posed character of the inverse problem. A detailed error analysis of the CLD allows for a predictive description of a posteriori constraints in the POCS framework. We discuss the application of this method to the characterization of simulated test cases and experimentally obtained data.
A global approach for reducing risks in hydrogenation operations
Authors: Karayigitoglu Cigdem , Holroyde John 
Published: September 2005

AbstractPfizer API manufacturing consists of 16 sites around the world and represents a large manufacturing capability. This network has expanded in recent years through mergers. This community of manufacturing sites represents a wide range of practical knowledge for conducting safe API (active pharmaceutical ingredient) manufacturing. Taking advantage of this wealth of experience, Pfizer manufacturing operations performed a global survey of hydrogenation current practices. From the information gathered, a “Hydrogen and Catalyst Handling Good Practice” guide was developed that covered the facility design and operational practices. The team that developed the “Good Practice” guide is also involved in overseeing the implementation of the recommended practices at all manufacturing sites conducting hydrogenations. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Reliable and effective inerting methods to prevent explosions
Authors: Hoppe Tom , Jaeger Norbert 
Published: September 2005

AbstractThis paper gives guidance on the use of inerting in the processing industry. It explains the different types of inerting methods available, the technical requirements for implementation of the methods, and their limitations. The report is intended to assist workers in plants with operations that need to be protected by inerting and reflects the present state of the art and current knowledge of the assessment and requirements associated with inerting. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Microstructural properties of Bi1.65Pb0.35Sr2Ca2Cu3O10+δ and Bi1.65Pb0.35Sr2CaCu2O8+δ ceramic samples through transport measurements: a comparative study
Authors: Govea‐Alcaide E. , Jardim R. F. , Muné P. 
Published: September 2005

AbstractWe have studied in detail the dependence of the electrical resistivity as a function of temperature of Bi1.65Pb0.35Sr2Ca2Cu3O10+δ ((Bi,Pb)‐2223) and Bi1.65Pb0.35Sr2CaCu2O8+δ ((Bi,Pb)‐2212) ceramic samples. Both types of samples were obtained by a solid‐state reaction method and pressed uniaxially at different compacting pressures ranging from 90 to 600 MPa before the last heat treatment. From electrical resistivity measurements as a function of temperature, we were able to separate contributions arising from both the grains' misalignment and microstructural defects, by using a current‐conduction model. The results suggest that in both compounds the texture degree and the connectivity between grains are improved with increasing compacting pressures. It was found that in the (Bi,Pb)‐2223 samples, even in those obtained at low compacting pressures, the grains exhibit a preferential orientation. A similar effect, but less pronounced, was observed in the (Bi,Pb)‐2212 samples. In both cases, the behavior is different to the one reported in YBCO ceramic samples, in which the grains exhibit random orientation. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)