bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of the Phase Morphology on the Optoelectronic Properties of Light‐Emitting Electrochemical Cells
Authors: Wenzl F. P. , Pachler P. , Suess C. , Haase A. , List E. J. W. , Poelt P. , Somitsch D. , Knoll P. , Scherf U. , Leising G. 
Published: May 2004

AbstractWe report on the morphological aspects of thin films prepared from a blue–green light‐emitting conjugated polymer, (methyl‐substituted ladder‐type poly(p‐phenylene, mLPPP)), blended with a solid‐state electrolyte composed either by a crown ether, dicyclohexano‐18‐crown‐6 (DCH18C6), or a high‐molecular‐weight poly(ethylene oxide) (HMWPEO), and a Li salt, lithium trifluoromethanesulfonate (LiCF3SO3, Li triflate (LiTf)), as they have been successfully applied in light‐emitting electrochemical cells (LECs). The surface morphologies of the blend layers were investigated using atomic force microscopy (AFM) in tapping mode, and the ion distribution was probed using X‐ray analysis by means of energy‐dispersive X‐ray spectrometry (EDXS) in the scanning electron microscope (SEM). We show that the two different phase‐separation processes, the complexation tendencies of the ionic species as well as the ionic transport numbers, have tremendous influence on the performances of the corresponding LECs, revealing either rectifying or symmetric optoelectronic characteristics in forward and reverse bias directions. This opens up new possibilities for tuning the optoelectronic properties of ion‐supported organic electronic devices.
Alkyl Substituent Effects on the Conductivity of Polyaniline
Authors: Zaidi N. A. , Foreman J. P. , Tzamalis G. , Monkman S. C. , Monkman A. P. 
Published: May 2004

AbstractThe oxidative polymerization of aniline hydrochloride derivatives in water at low temperature is studied without lithium chloride. The resulting polymers have high molecular weight but the conductivity of the acid‐doped films is strongly dependent on the alkyl‐substituted chain at the 2‐positions. The root cause of the alkyl‐substitution effects is thoroughly investigated using density functional theory (DFT) methods (B3LYP using 6–1G(d,p) and 6‐311++G(2d,2p) basis sets). Internal structural changes observed on substitution appear to be more significant than a variety of electronic parameters measured using the natural bond orbital (NBO) method. Interplanar angles steadily increase on substitution, whereas ring orbital properties and the amount of ring delocalization remain fairly constant. An investigation into the extent to which lone pair–σ‐orbital overlap is affected by substitution indicates that increasing the steric bulk of the substituent reduces the ability of the lone pair to delocalize into the ring orbitals. However, the amount of overlap between the two is not adversely affected until the dihedral between them is > 30°, a situation that only occurs in i‐propyl and s‐butyl substitution. This finding is completely reflected in the experimental conductivity measurements.
Interface Engineering for Solid‐State Dye‐Sensitized Nanocrystalline Solar Cells: The Use of Ion‐Solvating Hole‐Transporting Polymers
Authors: Haque S. A. , Park T. , Xu C. , Koops S. , Schulte N. , Potter R. J. , Holmes A. B. , Durrant J. R. 
Published: May 2004

AbstractThe control of interfacial charge transfer is central to the design of photovoltaic devices. This charge transfer is strongly dependent upon the local chemical environment at each interface. In this paper we report a methodology for the fabrication of a novel nanostructured multicomponent film, employing a dual‐function supramolecular organic semiconductor to allow molecular‐level control of the local chemical composition at a nanostructured inorganic/organic semiconductor heterojunction. The multicomponent film comprises a lithium ion doped dual‐functional hole‐transporting material (Li+–DFHTM), sandwiched between a dye‐sensitized nanocrystalline TiO2 film and a mono‐functional organic hole‐transporting material (MFHTM). The DFHTM consists of a conjugated organic semiconductor with ion supporting side chains, designed to allow both electronic and ionic charge transport properties. The Li+–DFHTM layers provide a new and versatile way to control the interface electrostatics, and consequently the charge transfer, at a nanostructured dye‐sensitized inorganic/organic semiconductor heterojunction.
Estimation of copolymerization kinetic parameters by maximum likelihood method
Authors: Habibi Ali , Vasheghani‐Farahani Ebrahim 
Published: May 2004

AbstractA kinetic study of free‐radical solution copolymerization of isobutyl methacrylate and lauryl methacrylate in benzene, initiated with 2,2‐azoisobutyronitrile (AIBN) was performed at different monomer feed compositions, at low conversion level. To avoid the complications of copolymerization kinetics, the compositional‐averaged rate constant method was applied to dead‐end polymerization in constant and variable volume polymerization systems. A conditional probability approach, with “maximum likelihood function” (MLF), was used for estimating the kinetic parameters from experimental data. This method provides point estimates as well as joint probability regions. The validity of this method was approved for the statistically justified and best estimation of the rate parameters in copolymerization systems. Statistical analysis indicated that, although copolymer composition is well described by the terminal unit model (TUM), the rate data are not. Like many other systems recently examined, the data were well represented by the implicit penultimate unit effect (IPUE) model of Fukuda and coworkers. It was found that the coupled rate parameter k̄p/k̄ is greater than the TUM predictions, whereas most of the previous systems studied have coupled rate parameters lower than those predicted by the TUM. An interactive computer simulator for parameter estimation was developed, which is run in two modes of estimation and prediction and is capable of receiving input data from both keyboard and databank. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1260–1272, 2004
Prediction of critical points: A new methodology using global optimization
Authors: Henderson Nélio , Freitas Léa , Platt Gustavo M. 
Published: May 2004

AbstractIn the present work we develop, implement, and analyze the results of a new methodology destined to calculate critical points of phase transitions. Our criticality conditions are developed from a slight modification of the Gibbs tangent plane criterion. We formulate the critical points calculation as an optimization problem. Such formulation offers many advantages, among them we can mention the capability of determining more than one critical point, the use of robust numerical methods, and the possibility of visualization of the critical phenomenon from a two‐variable (T and P) objective function. To solve the optimization problems we use the simulated annealing algorithm, a stochastic method whose convergence does not depend on initial guesses and gives preference to global optima. Several samples of mixtures were used to test the present methodology. The results of our simulations were compared, in a satisfactory way, with experimental data and with some results calculated in other approaches. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1300–1314, 2004
Is cascade testing a sensible method of screening a population for autosomal recessive disorders?
Authors: Morris J.K. , Law M.R. , Wald N.J. 
Published: May 2004

AbstractOur aim was to evaluate “cascade testing” as a method of screening a population for autosomal recessive disorders. We used computer simulations to estimate screening performance according to carrier frequency, whether testing would extend to siblings, first or second cousins of identified carriers and family size. Cascade testing in populations with the distribution of family size current in England and Wales would require locating and testing a small proportion of the population as expected, but would detect few cases. For cystic fibrosis (carrier frequency of 4%), testing all siblings and first cousins of all identified carriers would require locating and testing only 1.9% of the whole population, but would detect only 15% of all new cases. Similarly for congenital adrenal hyperplasia (carrier frequency of 1%), testing all siblings and first cousins of all identified carriers would require locating and testing only 0.1% of the whole population, but would detect only 3.1% of all new cases. The detection rate increases with increasing carrier frequency, family size and extending the testing to second cousins of identified carriers, but at the cost of greater increases in the proportion of the population located and tested. The performance of cascade testing is too poor to justify its introduction into practice as a screening test for any autosomal recessive disorder. © 2004 Wiley‐Liss, Inc.
Early hearing detection and intervention programs: Opportunities for genetic services
Authors: White Karl R. 
Published: May 2004

AbstractCongenital hearing loss is relatively frequent and has serious negative consequences if it is not diagnosed and treated during the first few months of life. Babies with hearing loss who are identified early and provided with appropriate intervention develop better language, cognitive, and social skills. As a result of improvements in screening equipment and procedures, newborn hearing screening programs have expanded rapidly in recent years, and almost 90% of all newborns are now screened for hearing loss before leaving the hospital. Because 50% or more of congenital hearing loss is due to genetic causes, providers of genetic services should play an increasingly important role in newborn hearing screening, diagnostic, and intervention services. For this to happen, parents, public health officials, and primary health care providers need to become better informed about the benefits of genetic services for children with hearing loss and their families. Providers of genetic services also need to become better informed about the current status of Early Hearing Detection and Intervention (EHDI) programs and how they can contribute to continued improvement of these programs. © 2004 Wiley‐Liss, Inc.
Interstitial deletion of chromosome 2q32‐34 associated with multiple congenital anomalies and a urea cycle defect (CPS I deficiency)
Authors: Loscalzo M.L. , Galczynski R.L. , Hamosh A. , Summar M. , Chinsky J.M. , Thomas G.H. 
Published: May 2004

AbstractA de novo deletion of the long arm of chromosome 2 at 2q31‐33 was observed in the fetal amniocyte G‐banded karyotype performed because of possible multiple malformations identified by ultrasound at 23 weeks gestation. Two days after the uneventful term delivery of a 2.45 kg male, the neonate experienced cardiopulmonary decompensation and biochemical changes compatible with carbamoyl phosphate synthetase I (CPS I) deficiency (elevated ammonia with a peak of 948 μmol/L, deficiency of citrulline, and no increase in orotic acid). The child died on day 3 of life. Physical anomalies confirmed at autopsy included double superior vena cava, ectopic adrenal tissue, and metatarsus adductus. The autopsy also revealed histologic evidence consistent with CPS deficiency, most notably microvesicular steatosis of the liver and Alzheimers Type II changes with hypertrophic astrocytes in the basal ganglia. A postnatal lymphocyte karyotype confirmed the chromosome 2q31‐33 deletion. Enzyme analysis on postmortem liver tissue confirmed the diagnosis of CPS deficiency.CPS Iis reported to be mapped to 2q35 by NCBI (http://www.ncbi.nlm.nih.gov/mapview/) and 2q34 by ENSEMBL (http://www.ensembl.org/). The UCSC Human Genome Browser July 2003 assembly also places the gene at 2q34 (http://genome.UCSC.edu/). Fluorescence in situ hybridization (FISH) analysis with a BAC clone (RP11‐349G4) ofCPS Idemonstrated that one copy of the gene was deleted in this infant. Using additional probes corresponding to the bands in the region of deletion, we identified the deleted region as 2q32‐2q34. Our observations support theCPS Imap position (ENSEMBL, UCSC) at 2q34. Additionally, potential conditions associated with deletions narrowly defined by standard cytogenetic techniques merit consideration in prenatal counseling. As demonstrated here, deletions may not only result in malformations and mental retardation but also increase the likelihood of revealing mutated genes located in the undeleted region of the homologous chromosome. © 2004 Wiley‐Liss, Inc.
Osteopathia striata with cranial sclerosis: Clinical, radiological, and bone histological findings in an adolescent girl
Authors: Ward L.M. , Rauch F. , Travers R. , Roy M. , Montes J. , Chabot G. , Glorieux F.H. 
Published: May 2004

AbstractOsteopathia striata with cranial sclerosis (OS–CS) is a rare skeletal dysplasia characterized by linear striations of the long bones, osteosclerosis of the cranium, and extra‐skeletal anomalies. We provide a comprehensive description of the skeletal phenotype in a French‐Canadian girl with a moderate to severe form of sporadic OS–CS. Multiple medical problems, including anal stenosis and the Pierre–Robin sequence, were evident in the first few years of life. At 14 years, she was fully mobile, with normal intellect and stature. She suffered chronic lower extremity pain in the absence of fractures, as well as severe headaches, unilateral facial paralysis, and bilateral mixed hearing loss. Biochemical indices of bone and mineral metabolism were within normal limits. Bone densitometry showed increased areal bone mineral density in the skull, trunk, and pelvis, but not in the upper and lower extremities. An iliac bone biopsy specimen revealed an increased amount of trabecular bone. Trabeculae were abnormally thick, but there was no evidence of disturbed bone remodeling. In a cranial bone specimen, multiple layers of periosteal bone were found that covered a compact cortical compartment containing tightly packed haversian canals. Bone lamellation was normal in both the iliac and skull samples. Osteoclast differentiation studies showed that peripheral blood osteoclast precursors from this patient formed functional osteoclasts in vitro. Thus, studies of bone metabolism did not explain why bone mass is increased in most skeletal areas of this patient. Cranial histology points to exuberant periosteal bone formation as a potential cause of the cranial sclerosis. © 2004 Wiley‐Liss, Inc.
Polymorphisms in the methylenetetrahydrofolate reductase and methionine synthase reductase genes and homocysteine levels in Brazilian children
Authors: Aléssio Ana Claudia M. , Annichino‐Bizzacchi Joyce M. , Bydlowski Sergio P. , Eberlin Marcos N. , Vellasco Adriana P. , Höehr Nelci Fenalti 
Published: May 2004

AbstractHyperhomocysteinemia is a risk factor for thrombosis, and methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) polymorphisms, folate, and B12 levels could contribute to plasma homocysteine (Hcy) variation. Although well established in adults, few studies have been performed in childhood. In this study, we investigated association of polymorphisms C677T and A1298C in the MTHFR gene and A66G in the MTRR gene with Hcy levels in children. These polymorphisms, as well as Hcy, folate, and vitamin B12 levels were investigated in 220 normal children with ages ranging from 1 to 8 years. Plasma Hcy, folate, and vitamin B12 levels were normal in all children. None of the polymorphisms could be considered an independent risk factor for hyperhomocysteinemia during childhood. The median Hcy levels in 37 children (17%) doubly heterozygous for C677T and A1298C mutations in the MTHFR gene were not different from the other genotypes. However, the association of the different genotypes with Hcy, folate, and vitamin B12 levels demonstrated significant P‐values. The folate levels demonstrated a statistically significant decrease (P = 0.0477) from the C677T mutation in the MTHFR gene (TT genotype) when compared to the other groups. Folate was the only independent risk factor for hyperhomocysteinemia. Thus, monitoring the concentrations of folate would be more helpful for evaluating hyperhomocysteinemia and for preventing cardiovascular disease. © 2004 Wiley‐Liss, Inc.
Mesomelic dysplasia, Kantaputra type: Clinical report, prenatal diagnosis, no evidence for SHOX deletion/mutation
Authors: Kwee M.L. , van de Sluijs J.A. , van Vugt J.M.G. , Wijnaendts L.C.D. , Gille J.J.P. 
Published: May 2004

AbstractA grandmother, her three children, and three grandchildren had skeletal abnormalities consisting of a short stature, bilateral symmetrical very short, broad and bowed radii, very short and broad ulna, mildly short lower legs, short proximal end of fibula, abnormal ankles, abnormal calcaneus and talus and pes equinus. They had normal craniofacial features, normal intelligence and normal chromosomes. We concluded that this skeletal dysplasia resembles the autosomal dominant mesomelic dysplasia, Kantaputra type. Prenatal diagnosis by ultrasound examination early in the pregnancy was possible. We found no evidence for a SHOX gene deletion or point mutation. As far as we know this is the third reported family with this skeletal dysplasia. © 2004 Wiley‐Liss, Inc.
Earliest Miocene hominoid from Southeast Asia
Authors: Kunimatsu Yutaka , Ratanasthien Benjavun , Nakaya Hideo , Saegusa Haruo , Nagaoka Shinji 
Published: May 2004

AbstractA new hominoid fossil site, Chiang Muan in northern Thailand, yielded the first finding of a large‐bodied Miocene hominoid in Southeast Asia. This specimen (CMu6‐1′00) was preliminarily reported by Kunimatsu et al. ([2000a] Primate Res. 16:299). Later, Chaimanee et al. ([ 2003] Nature 422:61–65) reported additional hominoid teeth from the same site, but all of them were collected from younger deposits (the Upper Lignite Member, in Nagaoka and Suganuma [ 2002] Primate Res 18:159–164). The specimen described here (CMu6‐1′00) was recovered from the Lower Lignite Member (Nagaoka and Suganuma [ 2002] Primate Res 18:159–164), which is probably several hundred thousand years older than the Upper Lignite Member (Suganuma et al. [ 2002] Primate Res. 18:165–173). This article provides a detailed description of this hominoid specimen and paleontological/geological data of the fossil site at Chiang Muan. The hominoid specimen (CMu6‐1′00) is an isolated upper molar (right M1 or M2), similar in size to modern orangutans (Pongo pygmaeus). This upper molar has low and voluminous cusps, relatively thick enamel, and relatively low relief of the dentine/enamel junction, with only a faint remnant of the lingual cingulum. The age of Chiang Muan is estimated to be the latest Middle Miocene (ca. 11–12 Ma), based on the mammalian fossils (Nakaya et al. [ 2002] Primate Res. 18:131–141) and paleomagnetic study (Suganuma et al. [ 2002] Primate Res. 18:165–173). This suggests that the Chiang Muan Hominoid in the present study is an earlier member of Eastern Eurasian Miocene hominoids. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Demographic parameters and life history of chimpanzees at Bossou, Guinea
Authors: Sugiyama Yukimaru 
Published: May 2004

AbstractDemographic parameters of wild chimpanzees at Bossou, Guinea, are presented and compared with those of other populations. The population size of Bossou chimpanzees has been stable over the last 26 years, except during two incidents of partial deforestation. The annual birth rate for a female (mean = 0.194, but 0.165 when the infant survived more than 4 years) and interbirth interval are not much different from those of other study sites. The primiparous age of Bossou chimpanzees, however, is far younger (mean = 10.9 years) than for all other known wild chimpanzee populations. The infant and juvenile survival rate is also the highest (female = 0.64, male = 0.52 for the first 8 years). As a result, the lifetime reproductive success of Bossou chimpanzees is estimated to be highest among long‐term study sites. The rate of disappearance from Bossou dramatically increases during the adolescent stage, and most young chimpanzees disappear before or around maturation. Probably because the environmental capacity for chimpanzees at Bossou is at its limit, many young independent males, as well as females, have to disperse, though others may die. For chimpanzee alpha males of other populations, mature males may be needed as collaborators to defend resources. In the case of Bossou, however, a lack of adjacent groups, conspecific competitors, predators, and perhaps medium‐sized mammals as prey for group hunting may eliminate this need of the alpha male for other males. The reasons why all males of other chimpanzee populations persist in being philopatric for life and maintain kin‐related male bonds differing from most mammal species, including humans, are discussed. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Brain size and encephalization in early to Mid‐Pleistocene Homo
Authors: Rightmire G. Philip 
Published: May 2004

AbstractImportant changes in the brain have occurred during the course of human evolution. Both absolute and relative size increases can be documented for species of Homo, culminating in the appearance of modern humans. One species that is particularly well‐represented by fossil crania is Homo erectus. The mean capacity for 30 individuals is 973 cm3. Within this group there is substantial variation, but brain size increases slightly in specimens from later time periods. Other Middle Pleistocene crania differ from those of Homo erectus. Characters of the facial skeleton, vault, and cranial base suggest that fossils from sites such as Arago Cave in France, the Sima de los Huesos in Spain, Bodo in Ethiopia, Broken Hill in Zambia, and perhaps Dali in China belong to the taxon Homo heidelbergensis. Ten of these mid‐Quaternary hominins have brains averaging 1,206 cm3 in volume, and many fall beyond the limits of size predicted for Homo erectus of equivalent age. When orbit height is used to construct an index of relative brain size, it is apparent that the (significant) increase in volume documented for the Middle Pleistocene individuals is not simply a consequence of larger body mass. Encephalization quotient values confirm this finding. These changes in absolute and relative brain size can be taken as further corroborative evidence for a speciation event, in which Homo erectus produced a daughter lineage. It is probable that Homo heidelbergensis originated in Africa or western Eurasia and then ranged widely across the Old World. Archaeological traces indicate that these populations differed in their technology and behavior from earlier hominins. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
CO2‐assisted polymer processing: A new alternative for intractable polymers
Authors: Garcia‐Leiner Manuel , Lesser Alan J. 
Published: May 2004

AbstractCO2‐assisted polymer processing is proposed as an alternative route for intractable and high molecular weight polymers based on the plasticization effects of CO2 and its direct effect on the melting behavior of semicrystalline polymers. A modified processing system was used to process a variety of polymers in the presence of high‐pressure CO2. The system includes an extruder that was modified to allow for high pressures created by the injection of CO2. The new design includes a modified feed section that allows a given mass of polymer to interact with CO2 before and during the extrusion process. The inherent shear mixing and the presence of CO2 allow for a specific control over the extrudate morphology. Results suggest that this alternative design provides a new and easy route to melt process high melt viscosity polymers of commercial importance, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), and syndiotactic polystyrene (s‐PS). The increased processability of these systems in CO2 is related to the plasticization effect of CO2 that was quantified through a depression in the glass‐transition temperature according to the Chow model. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1501–1511, 2004