bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Modeling of Human Fecundity
Authors: Sundaram Rajeshwari , Buck Louis Germaine M. , Kim Sungduk 
Published: March 2010

AbstractHuman fecundity is of great interest to reproductive scientists, as well as to couples trying to conceive. It is measured by the probability of pregnancy in a menstrual cycle for a sexually active couple who is not contracepting. Reproductive epidemiologists are interested in models for human fecundity to identify the determinants and to identify preventable causes of reproductive dysfunction. There is also suspicion that various environmental factors negatively affect the human fertility. Motivated by these issues, there has been considerable interest in developing biologically precise statistical models for human fecundity. This chapter begins with a brief discussion of various biological and behavioral factors that potentially impact pregnancy. Furthermore, emphasis is made on various biological and behavioral factors that impact pregnancy but are not measurable. Next, we review various statistical models for pregnancy that are available in literature, with emphasis on models that are biologically relevant. We also indicate some outstanding issues that need to be addressed to build stronger statistical models that are biologically valid. We conclude with an analysis of the New York Anglers Cohort Prospective Pregnancy study.
Panel Count Data
Authors: Sun Jianguo 
Published: March 2010

AbstractPanel count data usually refer to data arising from studies on recurrent events in which study subjects are followed or observed only periodically rather than continuously. In these situations, the objective of interest is about the occurrence of some events that can occur multiple times or repeatedly and the studies resulting in this type of information are often referred to as event history studies. There are many fields that produce panel count data and they include medical studies, reliability experiments and social science. This article will review some basic concepts about panel count data, some common issues and questions of interest in their analysis as well as the corresponding statistical procedures that are available. In particular, we will discuss estimation of the mean function of the underlying counting process characterizing the occurrence of the events, comparison of several processes and regression analysis of panel count data. Some discussion will also be provided for situations that involve dependent or informative observation processes.
Centralized Genomic Control: A Simple Approach Correcting for Population Structures
Authors: Zhang Hong , Li Qizhai , Zang Yong , Yang Yaning , Zheng Gang 
Published: March 2010

Abstract
The case‐control study is a useful design for testing for genetic association. However, it may yield spurious associations due to population structure. Population stratification (PS) and cryptic relatedness (CR) are two common population structures under which the trend test for association may be biased and its variance may be distorted. Genomic control and delta centralization are two simple approaches to correct for the variance distortion and the bias, respectively, using unlinked null genetic markers. An alternative simple method, centralized genomic control (CGC), that corrects for both bias and variance distortions simultaneously using unlinked null markers is studied. It can also handle studies with a small number of subjects and a small number of null markers. This approach requires the allele frequencies of the markers of interest roughly to match those of unlinked null markers in control samples. This matching and the effectiveness of various approaches under the matching are investigated by simulation studies. Applications to two real datasets (a candidate gene study and a genome‐wide association study) illustrate that the CGC outperforms the existing methods which correct for either the variance distortion or the bias due to PS or CR.
Effect of Grain Size Reduction and Geometrical Confinement in Fine Grained Copper: Potential Applications as a Material for Reversible Electrical Contacts
Authors: Champion Yannick , Bréchet Yves 
Published: March 2010

AbstractThe potential of ultrafine grained copper as a material for reversible electrical contact is investigated. The influence of grain size and sample size on strength and electrical properties is discussed. The existence of an optimal grain size and the relevance of size effects for the mechanical properties are analyzed.
Molecular Engineering of Blue Fluorescent Molecules Based on Silicon End‐Capped Diphenylaminofluorene Derivatives for Efficient Organic Light‐Emitting Materials
Authors: Lee Kum Hee , Kang Lee Kyung , Lee Jin Yong , Kang Sunwoo , Jeon Soon Ok , Yook Kyoung Soo , Lee Jun Yeob , Yoon Seung Soo 
Published: March 2010

AbstractBlue fluorescent materials based on silicone end‐capped 2‐diphenylaminofluorene derivatives are synthesized and characterized. These materials are doped into a 2‐methyl‐9,10‐di‐[2‐naphthyl]anthracene host as blue dopant materials in the emitting layer of organic light‐emitting diode devices bearing a structure of ITO/DNTPD (60 nm)/NPB (30 nm)/emitting layer (30 nm)/Alq3 (20 nm)/LiF (1.0 nm)/Al (200 nm). All devices exhibit highly efficient blue electroluminescence with high external quantum efficiencies (3.47%–7.34% at 20 mA cm−2). The best luminous efficiency of 11.2 cd A−1 and highest quantum efficiency of 7.34% at 20 mA cm−2 are obtained in a device with CIE coordinates (0.15, 0.25). A deep‐blue OLED with CIE coordinates (0.15, 0.14) exhibits a luminous efficiency of 3.70 cd A−1 and quantum efficiency of 3.47% at 20 mA cm−2.
The Critical Role of the Underlayer Material and Thickness in Growing Vertically Aligned Carbon Nanotubes and Nanofibers on Metallic Substrates by Chemical Vapor Deposition
Authors: Nessim Gilbert D. , Acquaviva Donatello , Seita Matteo , O'Brien Kevin P. , Thompson Carl V. 
Published: March 2010

AbstractVertically aligned carbon nanotubes and nanofibers are grown on metallic Ta and Pd underlayers at temperatures below 500 °C. Controlling the size of the grains of the underlayer film is critical because this leads to a more uniform distribution of catalyst dots, which in turn results in vertical alignment of the carbon nanostructures. Rapid and limited heating and appropriate materials selection can also be used to limit catalyst/underlayer reactions that hinder or suppress carbon nanostructure growth or that lead to entangled growth. Control of catalyst reactivity with metallic underlayers is significant because growth on conductive substrates is notoriously difficult, but needed for many applications such as the use of carbon nanostructures in microelectronic circuits.
Model‐based optimization of hydrogen generation by methane steam reforming in autothermal packed‐bed membrane reformer
Authors: Simakov David S. A. , Sheintuch Moshe 
Published: March 2010

AbstractAn autothermal membrane reformer comprising two separated compartments, a methane oxidation catalytic bed and a methane steam reforming bed, which hosts hydrogen separation membranes, is optimized for hydrogen production by steam reforming of methane to power a polymer electrolyte membrane fuel cell (PEMFC) stack. Capitalizing on recent experimental demonstrations of hydrogen production in such a reactor, we develop here an appropriate model, validate it with experimental data and then use it for the hydrogen generation optimization in terms of the reformer efficiency and power output. The optimized reformer, with adequate hydrogen separation area, optimized exothermic‐to‐endothermic feed ratio and reduced heat losses, is shown to be capable to fuel kW‐range PEMFC stacks, with a methane‐to‐hydrogen conversion efficiency of up to 0.8. This is expected to provide an overall methane‐to‐electric power efficiency of a combined reformer‐fuel cell unit of ∼0.5. Recycling of steam reforming effluent to the oxidation bed for combustion of unreacted and unseparated compounds is expected to provide an additional efficiency gain. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Intra‐individual variability in genetic and environmental models of attention‐deficit/hyperactivity disorder
Authors: Perry G.M.L. , Sagvolden T. , Faraone S.V. 
Published: March 2010

AbstractThe frequent observation of intra‐individual variability (IIV) in the expression of ADHD symptoms suggest that IIV is an integral component of the disorder. We tested IIV in ADHD‐like phenotype from five different studies of rodent models of ADHD, including studies with Spontaneous Hypertensive Rats (SHR/NCrl and SHR/N), Wistar‐Kyoto Hyperactive Rats (WKHA/N), Wistar‐Kyoto Hypertensive rat (WKHT), PCB‐126 and ‐153‐treated Lewis rats and behaviorally normal Wistar/Mol, Wistar‐Kyoto (WKY/N and WKY/NMol), and untreated Lewis rats. Averages of the absolute residual deviation of ADHD‐like behavior from individual means (“individual phenotypic dispersion,” PDi) were used to represent IIV in the fixed‐interval (FI) and extinction (EXT) phases of operant behavioral activity. Across all studies, SHR rats had higher PDi than WKY rats (P < 0.0001) for all ADHD‐like traits, and higher PDi for hyperactivity than WKHT and WKHA/N rats. Male SHR rats in particular had higher PDi for hyperactivity than male or female WKYs, SHR females for EXT hyperactivity, and higher dispersion for inattention than WKY females. These findings strongly suggest the genetic control of IIV, and suggest that the SHR may be a useful model for the identification of genes for IIV in human ADHD. These findings also obliquely support the SHR as a useful model for ADHD overall. © 2010 Wiley‐Liss, Inc.
No association of the serotonin transporter polymorphisms 5‐HTTLPR and RS25531 with schizophrenia or neurocognition
Authors: Konneker Thomas I. , Crowley James J. , Quackenbush Corey R. , Keefe Richard S.E. , Perkins Diana O. , Stroup T. Scott , Lieberman Jeffrey A. , van den Oord Edwin , Sullivan Patrick F. 
Published: March 2010

AbstractA promoter polymorphism in the serotonin transporter gene has been widely studied in neuropsychiatry. We genotyped the 5‐HTTLPR/rs25531 triallelic polymorphism in 728 schizophrenia cases from the CATIE study and 724 control subjects. In a logistic regression with case/control status as dependent variable and 7 ancestry‐informative principal components as covariates, the effect of 5‐HTTLPR/rs25531 composite genotype was not significant (odds ratio = 1.008, 95% CI 0.868–1.172, P = 0.91). In cases only, 5‐HTTLPR/rs25531 was not associated with neurocognition (summary neurocognitive index P = 0.21, working memory P = 0.32) or symptomatology (PANSS positive P = 0.67 and negative symptoms P = 0.46). We were unable to identify association of the triallelic 5‐HTTLPR with schizophrenia, neurocognition, or core psychotic symptoms even at levels of significance unadjusted for multiple comparisons. © 2010 Wiley‐Liss, Inc.
Neutral and Oxidized Triisopropylsilyl End‐Capped Oligothienoacenes: A Combined Electrochemical, Spectroscopic, and Theoretical Study
Authors: Aragó Juan , Viruela Pedro M. , Ortí Enrique , Malavé Osuna Reyes , Vercelli Barbara , Zotti Gianni , Hernández Víctor , López Navarrete Juan T. , Henssler John T. , Matzger Adam J. , Suzuki Yoshitake , Yamaguchi Shigehiro 
Published: March 2010

AbstractThis work presents an analysis of the structural, electrochemical, and optical properties of a family of triisopropylsilyl end‐capped oligothienoacenes (TIPS‐Tn‐TIPS, n=4–8) by combining cyclic voltammetry, spectroscopic techniques, and quantum‐chemical calculations. TIPS‐Tn‐TIPS compounds form stable radical cations, and dications are only obtained for the longest oligomers (n=7 and 8). Oxidation leads to the quinoidization of the conjugated backbone, from which electrons are mainly extracted. The absorption and fluorescence spectra show partially resolved vibronic structures even at room temperature, due to the rigid molecular geometry. Two well‐resolved vibronic progressions are observed at low temperatures due to the vibronic coupling, with normal modes showing wavenumbers of ≈1525 and ≈480 cm−1. Optical absorption bands display remarkable bathochromic dispersion with the oligomer length, indicative of the extent of π conjugation. The optical properties of the oxidized compounds are characterized by in situ UV/Vis/NIR spectroelectrochemistry. The radical cation species show two intense absorption bands emerging at energies lower than in the neutral compounds. The formation of the dication is only detected for the heptamer and the octamer, and shows a new band at intermediate energies. Optical data are interpreted with the help of density functional theory calculations performed at the B3LYP/6‐31G** level, both for the neutral and the oxidized compounds.
Competitive Adsorption of Methylene Blue and Rhodamine B on Natural Zeolite: Thermodynamic and Kinetic Studies
Authors: Jafari‐zare Farhade , Habibi‐yangjeh Aziz 
Published: March 2010

AbstractA batch system was applied to study the adsorption behavior of methylene blue (MB) and rhodamine B (RB) in single and binary component systems on natural zeolite. In the single component systems, the zeolite presents higher adsorption capacity for MB than RB with the maximal adsorption capacity of 7.95×10−5 and 1.26×10−5 mol/g at 55°C for MB and RB, respectively. Kinetic studies indicated that the adsorption followed pseudo‐second‐ order kinetics and could be described by a two‐step diffusion process. For the single component systems, the adsorption isotherm could be fitted by the Langmuir model. In the binary component system, MB and RB exhibit competitive adsorption on the zeolite. The adsorption is approximately reduced to 50% and 60% of single component adsorption systems of MB and RB, respectively at an initial concentration of 6×10−6 mol·L−1 at 25°C. In the binary component system, kinetic and adsorption isotherm studies demonstrate that the experimental data are following pseudo‐second‐order kinetics and Langmuir isotherm and kinetic data are fairly described by a two‐step diffusion model. Effect of solution pH on adsorption of MB and RB in both single and binary component systems was studied and the results were described by electrostatic interactions.
Differential Kinetic Spectrophotometric Determination of Methamidophos and Fenitrothion in Water and Food Samples by Use of Chemometrics
Authors: Deng Na , Ni Yongnian , Kokot Serge 
Published: March 2010

AbstractA spectrophotometric method for simultaneous analysis of methamidophos and fenitrothion was proposed by application of chemometrics to the spectral kinetic data, which was based upon the difference in the inhibitory effect of the two pesticides on acetylcholinesterase (AChE) and the use of 5,5′‐dithiobis(2‐nitrobenzoic acid) (DTNB) as a chromogenic reagent for the thiocholine iodide (TChI) released from the acetylthiocholine iodide (ATChI) substrate. The absorbance of the chromogenic product was measured at 412 nm. The different experimental conditions affecting the development and stability of the chromogenic product were carefully studied and optimized. Linear calibration graphs were obtained in the concentration range of 0.5–7.5 ng·mL−1 and 5–75 ng·mL−1 for methamidophos and fenitrothion, respectively. Synthetic mixtures of the two pesticides were analysed, and the data obtained processed by chemometrics, such as partial least square (PLS), principal component regression (PCR), back propagation‐artificial neural network (BP‐ANN), radial basis function‐artificial neural network (RBF‐ANN) and principal component‐radial basis function‐artificial neural network (PC‐RBF‐ANN). The results show that the RBF‐ANN gives the lowest prediction errors of the five chemometric methods. Following the validation of the proposed method, it was applied to the determination of the pesticides in several commercial fruit and vegetable samples; and the standard addition method yielded satisfactory recoveries.
Synthesis of Novel Trispiroheterocycles through 1,3‐Dipolar Cycloaddition of Azomethine Ylides and Nitrile Oxide
Authors: Li Xiaofang , Yu Xianyong , Yi Pinggui 
Published: March 2010

AbstractThe 1,3‐dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and isatin to 1‐benzyl‐3,5‐diarylmethylidene‐piperidin‐4‐ones afforded novel di‐spiro‐indolo/pyrrolidino/piperidines in moderate yields. Further cycloaddition of these di‐spiro compounds to nitrile oxide afforded tri‐spiro‐indolo/pyrrolidino/piperadino/isoxazolines in moderate yields with high regio‐ and stereoselectivity.
Bimetallic Rare Earth Alkyl Complexes Bearing Bridged Amidinate Ligands: Synthesis and Activity for L‐Lactide Polymerization
Authors: Yang Jianping , Xu Ping , Luo Yunjie 
Published: March 2010

AbstractFour novel bridged‐amidines H2L {1,4‐R1[C(=NR2)(NHR2)]2 [R1=C6H4, R2=2,6‐iPr2C6H3 (H2L1); R1=C6H4, R2=2,6‐Me2C6H3 (H2L2); R1=C6H10, R2=2,6‐iPr2C6H3 (H2L3); R1=C6H10, R2=2,6‐Me2C6H3 (H2L4)]} were synthesized in 65%–78% isolated yields by the condensation reaction of dicarboxylic acid with four equimolar amounts of amines in the presence of PPSE at 180°C. Alkane elimination reaction of Ln(CH2SiMe3)3(THF)2 (Ln=Y, Lu) with 0.5 equiv. of amidine in THF at room temperature afforded the corresponding bimetallic rare earth alkyl complexes (THF)(Me3SiCH2)2LnL1Ln(CH2SiMe3)2(THF) [Ln=Y (1), Lu (2)], (THF)(Me3SiCH2)2LnL2Ln‐ (CH2SiMe3)2(THF) [Ln=Y (3), Lu (4)], (THF)(Me3SiCH2)2YL3Y(CH2SiMe3)2(THF) (5), (THF)(Me3SiCH2)2YL4‐ Y(CH2SiMe3)2(THF) (6) in 72% –80% isolated yields. These neutral complexes showed activity towards L‐lactide polymerization in toluene at 70°C to give high molecular weight (M>104) and narrow molecular weight distribution (Mw/Mn≦1.40) polymers
Synthesis, Spectral and Thermal Analyses of Novel Bi‐ and Polyhomonuclear Complexes of Pyrimidine Bisazo‐dianil Derivatives
Authors: El‐Wakiel Nadia , Khedr Abdalla , Mansour Ramadan 
Published: March 2010

AbstractSeven new bi‐ and polyhomonuclear transition metal complexes with three polyhydroxlated bisazodianil ligands were synthesized and characterized. The ligands were derived from condensation of 6‐(5‐formyl‐2‐hydroxyphenylazo)‐2,4‐dihydroxypyrimidine with aliphatic diamines (H8L1, H8L2 and H6L3). The data of elemental and thermal analyses, molar conductance measurement, IR, electronic and ESR spectra as well as magnetic moment measurements support the formation of [L1Co7Cl6(H2O)10]·22H2O (1), [H2L2Mn6Cl6(H2O)8]·3H2O·2EtOH (3), [L2Co8Cl8(H2O)12]·24H2O (4), [H4L3Co2Cl2(H2O)2]·8H2O·2EtOH (6) with a tetrahedral geometry and [H2L1Ni5Cl4(H2O)16]·19H2O·EtOH (2), [L2Ni8Cl8(H2O)28]·8H2O·EtOH (5) with an octahedral geometry while [H6L3Cu3(H2O)7]Cl3·10H2O (7) has a distorted tetrahedral arrangement. The mode of bonding between the metal ions and the ligand molecules is determined and the metal‐metal interaction was studied. The activation thermo‐kinetic parameters for the thermal decomposition steps of the complexes E*, ΔH*, ΔS*, and ΔG* were calculated.
FeCl3: Highly Efficient Catalyst for Synthesis of α‐Amino Nitriles
Authors: Heravi Majid M. , Ebrahimzadeh Mojgan , Oskooie Hossein A. , Baghernejad Bita 
Published: March 2010

Abstractα‐Amino nitriles are synthesized by the three‐component coupling reaction of aldehydes, amines and trimethylsilyl cyanide using FeCl3 as a solid acid catalyst, under solvent‐free conditions in good yields. The catalyst was recovered by simple filtration and was recycled in subsequent reactions.
Increased Restenosis Rates 12 Months After Coronary Implantation of the Sirolimus‐Eluting YUKON‐Choice Stent Compared to the Paclitaxel‐Eluting TAXUS Stent
Authors: Ruef Johannes , Störger Hans , Schwarz Franz , Haase Jürgen 
Published: March 2010

AbstractBackgroundPreviously the polymer‐free sirolimus‐eluting YUKON‐Choice stent (A) has demonstrated noninferiority compared to the polymer‐based paclitaxel‐eluting TAXUS stent (B). To test for long‐term equivalency in unselected real‐world coronary lesions of various complexities, we retrospectively compared both stents.MethodsA total of 410 patients with symptomatic coronary artery disease (CAD) were treated with stent A (n = 205) or stent B (n = 205). Baseline clinical characteristics, lesion location, and length and the number of stents implanted per lesion were equally distributed. Clinical follow‐up with assessment of major adverse cardiac events (MACE) and noncardiac deaths was obtained at 9 and 12 months.ResultsNominal stent diameter and nominal length of the stented segment were without differences between the groups. The incidence of MACE after 12 months was significantly higher in group A (35.1%) compared to group B (16.6%, P = .001). This was mainly due to increased rates of target‐lesion revascularizations in group A (13.7%) vs group B (4.4%, P = .005). No significant differences in target‐vessel revascularizations and non‐target‐vessel revascularizations were observed. In group B, 1 stent thrombosis was documented (0.5%) vs none in group A (P > .05); in each group 1 myocardial infarction (MI), but no cardiac deaths occurred; 3 noncardiac deaths in group A (1.5%) vs 7 in group B (3.4%) were observed (P = .3).ConclusionsIn contrast to our previous findings indicating no differences in MACE between patients treated with the polymer‐free sirolimus‐eluting YUKON‐Choice stent and the polymer‐based paclitaxel‐eluting TAXUS stent at 6 months, we herewith show that 12 months after percutaneous coronary intervention (PCI) of real‐world coronary lesions the YUKON stent appears to be inferior due to increased target‐lesion revascularization (TLR) rates as a consequence of delayed restenosis. Copyright © 2010 Wiley Periodicals, Inc.
Clinical Features of the Dilated Phase of Hypertrophic Cardiomyopathy in Comparison With Those of Dilated Cardiomyopathy
Authors: Hamada Tomoyuki , Kubo Toru , Kitaoka Hiroaki , Hirota Takayoshi , Hoshikawa Eri , Hayato Kayo , Shimizu Yuji , Okawa Makoto , Yamasaki Naohito , Matsumura Yoshihisa , Yabe Toshikazu , Takata Jun , Doi Yoshinori L. 
Published: March 2010

AbstractBackgroundAlthough the dilated phase of hypertrophic cardiomyopathy (D‐HCM) characterized by left ventricular (LV) systolic dysfunction and cavity dilatation has been reported to be a poor prognosis, this is now in contrast to the improved prognosis of dilated cardiomyopathy (DCM) in the era of advancements in heart failure management. There has been no investigation of the clinical features of D‐HCM compared with those of DCM from the point of management of systolic dysfunction.HypothesisThe aim of this study was to investigate the clinical features of D‐HCM in comparison with those of DCM in a single institute.MethodsWe studied 20 consecutive patients with D‐HCM (global ejection fraction < 50%) and 115 consecutive patients with DCM.ResultsAt diagnosis of D‐HCM, 8 (40%) of the D‐HCM patients already experienced dyspnea (New York Heart Association [NYHA] class ≥ III). Left atrial diameter was larger and prevalence of atrial fibrillation was higher in the D‐HCM group, although LV size was larger and LV ejection fraction was lower in the DCM group. During the follow‐up period (4.0 years), 11 (55%) of the patients with D‐HCM died. The 5‐year survival rate from all‐cause mortality including cardiac transplantation was 45.6% in patients with D‐HCM vs 81.6% in patients with DCM (log‐rank P = .0001).ConclusionsPatients with D‐HCM were more symptomatic at diagnosis, although LV dilatation and impaired fractional shortening seemed more severe in patients with DCM. The prognosis for D‐HCM patients was worse than that for patients with DCM despite similar or even more intensive treatment for heart failure. Copyright © 2010 Wiley Periodicals, Inc.