bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sperm morphology in the Malagasy rodents (Muroidea: Nesomyinae)
Authors: Ding Xiaodan , Leigh C.M. , Goodman S.M. , Bedford J.M. , Carleton M.D. , Breed W.G. 
Published: October 2010

AbstractThe morphology of the spermatozoon of representative species of the subfamily Nesomyinae (Muroidea: Nesomyidae), a monophyletic group of rodents endemic to Madagascar, was examined by light and electron microscopy to determine the sperm head shape and tail length across the species. Marked interspecific differences were found to occur in both the form of the sperm head and length of the tail. The species that possess a sperm head with an apical hook, which largely contains acrosomal material, generally displayed longer sperm tails, and a species with a spatulate sperm head had the shortest tail. The association between sperm head shape and tail length mirrors that previously found in Eurasian and Australasian murine rodents. Thus, the repeated association between sperm head shape and tail length across these groups of muroid rodents clearly indicates a functional relationship between these two features. A comparison of sperm morphology of the nesomyines to that of related muroid rodents on the mainland of Africa suggests that the possession of an apical hook is the ancestral condition. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.
Babbling, vegetative function, and language development after cricotracheal resection in aphonic children
Authors: Bohm Lauren A. , Nelson Marc E. , Driver Lynn E. , Green Glenn E. 
Published: October 2010

AbstractObjective:To determine the importance of prelinguistic babbling by studying patterns of speech and language development after cricotracheal resection in aphonic children.Study Design:Retrospective review of seven previously aphonic children who underwent cricotracheal resection by our pediatric thoracic airway team. The analyzed variables include age, sex, comorbidity, grade of stenosis, length of resected trachea, and communication methods.Methods:Data regarding the children's pre‐ and postsurgical communication methods, along with their utilization of speech therapy services, were obtained via speech–language pathology evaluations, clinical observations, and a standardized telephone survey supplemented by parental documentation. Postsurgical voice quality was assessed using the Pediatric Voice Outcomes Survey.Results:All seven subjects underwent tracheostomy prior to 2 months of age when corrected for prematurity. The subjects remained aphonic for the entire duration of cannulation. Following cricotracheal resection, they experienced an initial delay in speech acquisition. Vegetative functions were the first laryngeal sounds to emerge. Initially, the children were only able to produce these sounds reflexively, but they subsequently gained voluntary control over these laryngeal functions. All subjects underwent an identifiable stage of canonical babbling that often occurred concomitantly with vocalizations. This was followed by the emergence of true speech.Conclusions:The initial delay in speech acquisition observed following decannulation, along with the presence of a postsurgical canonical stage in all study subjects, supports the hypothesis that babbling is necessary for speech and language development. Furthermore, the presence of babbling is universally evident regardless of the age at which speech develops. Finally, there is no demonstrable correlation between preoperative sign language and rate of speech development.
The effect of blood inflow and B1‐field inhomogeneity on measurement of the arterial input function in axial 3D spoiled gradient echo dynamic contrast‐enhanced MRI
Authors: Roberts Caleb , Little Ross , Watson Yvonne , Zhao Sha , Buckley David L. , Parker Geoff J. M. 
Published: October 2010

AbstractA major potential confound in axial 3D dynamic contrast‐enhanced magnetic resonance imaging studies is the blood inflow effect; therefore, the choice of slice location for arterial input function measurement within the imaging volume must be considered carefully. The objective of this study was to use computer simulations, flow phantom, and in vivo studies to describe and understand the effect of blood inflow on the measurement of the arterial input function. All experiments were done at 1.5 T using a typical 3D dynamic contrast‐enhanced magnetic resonance imaging sequence, and arterial input functions were extracted for each slice in the imaging volume. We simulated a set of arterial input functions based on the same imaging parameters and accounted for blood inflow and radiofrequency field inhomogeneities. Measured arterial input functions along the vessel length from both in vivo and the flow phantom agreed with simulated arterial input functions and show large overestimations in the arterial input function in the first 30 mm of the vessel, whereas arterial input functions measured more centrally achieve accurate contrast agent concentrations. Use of inflow‐affected arterial input functions in tracer kinetic modeling shows potential errors of up to 80% in tissue microvascular parameters. These errors emphasize the importance of careful placement of the arterial input function definition location to avoid the effects of blood inflow. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
The contribution of chemical exchange to MRI frequency shifts in brain tissue
Authors: Shmueli Karin , Dodd Stephen J. , Li Tie‐Qiang , Duyn Jeff H. 
Published: October 2010

AbstractRecent high‐field MRI studies based on resonance frequency contrast have revealed brain structure with unprecedented detail. Although subtle magnetic susceptibility variations caused by iron and myelin seem to be important to this contrast, recent research on protein solutions suggests that chemical exchange between water and macromolecular protons may contribute substantially to the observed gray‐white matter frequency contrast. To investigate this, we performed spectroscopic MRI experiments at 14 T on samples of fixed human visual cortex and fresh pig brain. To allow direct observation of any exchange‐induced frequency shifts, these samples were soaked in reference chemicals (TSP and dioxane) that are assumed not to be involved in exchange. For both fresh and fixed tissues and with both reference chemicals, substantial negative exchange‐induced gray‐white matter frequency contrast (–6.3 to –13.5 ppb) was found, whereas intracortical contrast was negligible. The sign of the gray‐white matter exchange‐induced frequency difference was opposite to the overall gray‐white matter frequency difference observed in vivo. This suggests that exchange contributes to, but is not sufficient to explain, the frequency contrast in vivo and tissue susceptibility differences may have a greater contribution than previously thought. The exchange‐dependent contribution may report on tissue chemical composition and pH. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
High resolution three‐dimensional cardiac perfusion imaging using compartment‐based k‐t principal component analysis
Authors: Vitanis Viton , Manka Robert , Giese Daniel , Pedersen Henrik , Plein Sven , Boesiger Peter , Kozerke Sebastian 
Published: October 2010

AbstractThree‐dimensional myocardial perfusion imaging requires significant acceleration of data acquisition to achieve whole‐heart coverage with adequate spatial and temporal resolution. The present article introduces a compartment‐based k‐t principal component analysis reconstruction approach, which permits three‐dimensional perfusion imaging at 10‐fold nominal acceleration. Using numerical simulations, it is shown that the compartment‐based method results in accurate representations of dynamic signal intensity changes with significant improvements of temporal fidelity in comparison to conventional k‐t principal component analysis reconstructions. Comparison of the two methods based on rest and stress three‐dimensional perfusion data acquired with 2.3 × 2.3 × 10 mm3 during a 225 msec acquisition window in patients confirms the findings and demonstrates the potential of compartment‐based k‐t principal component analysis for highly accelerated three‐dimensional perfusion imaging. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Acquired amyloid neuropathy in a Portuguese patient after domino liver transplantation
Authors: Conceição Isabel , Evangelista Teresinha , Castro José , Pereira Pedro , Silvestre Ana , Coutinho Conceição A , de Carvalho Mamede 
Published: October 2010

AbstractFamilial amyloid polyneuropathy (FAP) is a progressive neuropathy with autonomic dysfunction. Domino liver transplantation (DLT), in which the liver of an FAP patient is transplanted into another patient, is routinely applied to compensate for the shortage of available organs. We report a patient who developed a clinical picture of FAP 9 years after a DLT from an FAP donor. Electrophysiological, neuropathological, and autonomic tests were administered. The patient presented with typical clinical features of FAP. Electrophysiological investigation confirmed a moderate sensorimotor axonal and autonomic neuropathy. Sural nerve biopsy confirmed the presence of amyloid deposits in the endoneurium. Skin biopsy at the ankle showed reduced intraepidermal nerve fiber density. Our report shows that FAP can develop in a recipient of an FAP liver. This suggests that careful longitudinal study is required to evaluate the risk of FAP polyneuropathy in patients who undergo domino liver transplantation. Muscle Nerve, 2010
Solution of piecewise constant delay systems using hybrid of block‐pulse and Chebyshev polynomials
Authors: Marzban H. R. , Shahsiah M. 
Published: October 2010

AbstractAn efficient numerical method for finding the solution of piecewise constant delay systems is presented. The method is based upon hybrid of block‐pulse functions and Chebyshev polynomials. The operational matrix of delay is constructed. The properties of hybrid functions together with the operational matrices of integration, delay and product are used to convert the delay differential equation to an algebraic equation, thus greatly simplifying the problem. The method is easy to implement and yields very accurate results. The validity and applicability of the proposed method are demonstrated by considering different types of delay systems. Copyright © 2010 John Wiley & Sons, Ltd.
Haplo‐insufficiency: a driving force in cancer
Authors: Berger Alice H , Pandolfi Pier Paolo 
Published: October 2010

AbstractIt was originally proposed that tumour suppressor genes (TSGs) act in a recessive manner. Instead, numerous TSGs, including p53 and PTEN, exhibit haplo‐insufficiency as a consequence of the dose‐dependency of TSG function. Due to the challenges of identifying haplo‐insufficient TSGs by human genetics analysis alone, mouse models play a pivotal role in firmly establishing the haplo‐insufficiency of a gene, as in the recent identification of DOK2 as a haplo‐insufficient lung TSG. In many cases, TSGs exhibit conditional or compound haplo‐insufficiency, in which loss of one TSG allele is functionally important only in certain settings or after compound loss of other genes. The 5q deletion syndrome (5q−) is a paradigm of compound haplo‐insufficiency and demonstrates the importance of combinatorial interactions to elicit specific phenotypes. These concepts must be integrated into basic science studies to avoid delay in the identification of important TSGs. In the clinical realm, the challenges for molecular pathologists are the development of quantitative measures that can accurately and systematically ascertain the status of haplo‐insufficient genes in tumour biopsies, and the use of this information to accurately predict prognosis and response to therapy. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Drug consumption and air pollution: an overview
Authors: Menichini Federica , Mudu Pierpaolo 
Published: October 2010

AbstractPurposeAcute respiratory symptoms are among the health effects of air pollution exposure. Studies over the past decades have linked respiratory drug use (consumption or sales) with changes in air pollution conditions.MethodsTwenty‐one studies were analyzed to discuss whether increased levels of air pollution are associated with the use of medications for respiratory diseases.ResultsEpidemiological studies agree that variation in the drug use is related to air pollution exposure. In panel studies, although asthmatics are more sensitive to air pollution effects, the increase in drug use was comparable and similar to non‐asthmatics. Ecological studies confirm a significant association in respiratory drug sales depending on the selected lags (that is the time elapsing between air pollution measurement and the resulting drug use). The results of a meta‐analysis of two ecological studies showed an increase in risk for increase in daily mean concentration of some pollutant (10 µg m−3). For Black Smoke RR = 1.007 (95% CI 1.004–1.011) for lag 1, and RR = 1.008 (95% CI 1.005–1.010) for lag 8. For Nitrogen dioxide, RR = 1.008 (95% CI 1.005–1.012) for lag 8 and for Sulfur dioxide, RR = 1.005 (95% CI 1.001–1.010) for lag 9.ConclusionsThe analysis of drug use provides useful data for the evaluation of risks which derive from exposure to air pollution. More studies are needed to measure the effects of air pollution on respiratory medication use. Lags of up to 14 days have to be considered and the pollutants to be considered should include particulate matter and ozone. Copyright © 2010 John Wiley & Sons, Ltd.
Theoretical investigation on chiral cinchona alkaloid salts‐catalyzed asymmetric epoxidation of cyclic enones
Authors: Lu Nan , Mi Shizhen , Chen Dezhan , Zhang Guiqiu 
Published: October 2010

AbstractChiral cinchona alkaloid salts‐catalyzed asymmetric epoxidation of 2‐cyclohexen‐1‐one with hydrogen peroxide (H2O2) has been investigated using density functional theory (DFT). The ring‐closure step is rate limiting in the catalytic reaction. The enantioselectivity‐determining step is initial nucleophilic addition involving two orientations of axial and equatorial. In (S)‐catalyst j‐mediated process, axial pathway is favored over equatorial leading to the major epoxide [2S,3S]‐3. An opposite enantiomer [2R,3R]‐3 is primarily generated in (R)‐catalyst k‐assisted case preferring equatorial pathway. The results indicate that the enantioselectivity of epoxidation is dominated by central chirality of the bifunctional catalysts in the activation of enone by primary amine salt via iminium formation and of H2O2 by tertiary amine reacting as a general base. The substituent effect is also discussed to clarify a tendency existing in experiment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Determination of some descriptors of the real world working on the fundamental identity of the basic concept and the origin of the electronegativity and the global hardness of atoms. Part 2: Computation of the dipole moments of some heteronuclear diatomics
Authors: Ghosh Dulal C. , Islam Nazmul 
Published: October 2010

AbstractTo garner further support of our conjecture that “the electronegativity and the hardness manifest two different descriptors of the one and the same fundamental property of atoms,” we have derived a formula of evaluating the dipole charge of heteronuclear diatomic molecules, A–B, in terms of the global hardness of the atoms as: q = a (Δη/ηA) + b, where, a and b are two constants, q is the dipole charge, Δη is the hardness difference of the two atoms A and B, and ηA is the hardness of the harder atom. In deriving the above formula, we have relied upon the fact that hardness, similar to the electronegativity, controls the physical process of charge rearrangement during the chemical event of molecule formation. We have calculated the dipole charge and dipole moment of as many as 39 different types of compounds of widely divergent physico‐chemical behavior in terms of the algorithm derived in the present work. The computed dipole charge and dipole moment reveals the known chemico‐physical behavior of such compounds under study. A comparative study of the nature of variation of theoretically evaluated and experimentally determined dipole moments plotted in as many as six figures reveal that there is an excellent agreement between the two sets of dipole data. Hence, the ansatz suggested for the calculation of the dipole charge in terms of the hardness data of the atoms forming the compound is extremely efficacious in computing the charge distribution. It further transpires that the assumed model of charge rearrangement during the event of molecule formation is realistic and supports our basic conjecture that operationally the two descriptors, the hardness and the electronegativity, are identical. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A novel 2D graphical representation of protein sequence based on individual amino acid
Authors: Yu Jia‐Feng , Sun Xiao , Wang Ji‐Hua 
Published: October 2010

AbstractThe primary structure, i.e., the amino acids sequence, plays determinant roles in dynamical folding process and stable structure of protein molecules, then how to put forward sequences based approaches to demonstrate the biological information of the primary sequence will facilitate correlative researches. In this article, we outline a novel 2D graphical representation on the basis of a selected pair of physiochemical properties of amino acids, which integrates both the electric and hydrophobic factors to demonstrate the characteristic features of proteins. This novel representation transforms protein into a zigzag curve uniquely and allows direct inspection of similarities/dissimilarities among different protein sequences with higher resolution than previous methods. From this representation, some efficient numerical descriptors are derived, by which we quantitatively analyze the evolutionary distances among the ND6 (NADH dehydrogenase subunit 6) protein sequences of eight species, the results are coincident with the actual evolutions, which illustrate the efficiencies of the present approach. This representation can also provide convenient tools and alternative studying strategies for protein sequences and structures analysis. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical investigation on the mechanism and kinetics of OH radical with ethylbenzene
Authors: Huang Mingqiang , Wang Zhenya , Hao Liqing , Zhang Weijun 
Published: October 2010

AbstractThe OH hydrogen abstraction and addition with ethylbenzene have been studied in the range 298–1000 K using quantum chemistry methods. The geometries and frequencies of the reactants, transition states, and products were performed at BH and HLYP/6‐311++G(d,p) level, single point calculation for all the stationary points were carried out at CCSD(T) calculations of the optimized structures with the same basis set. Nine different reaction paths are considered corresponding to two side chain, three possible ring hydrogen abstraction, and four kinds different OH addition. The results of the theoretical study indicate that at the room temperature the reaction proceeds almost exclusively through OH addition, and is predicted to occur dominantly at the ortho position, the calculated overall rate constant is 6.72 × 10−12 cm3 molecule−1 s−1, showing a very good agreement with available experimental data. Although negligible at low temperature, at 1000 K ring hydrogen abstraction accounts for about 32% of the total abstraction reaction, and the whole hydrogen abstraction makes up for 30% of the total reaction. This study may provide useful information on understanding the mechanistic features of OH‐initiated oxidation of ethylbenzene. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Atomic term symbols via partitioning techniques
Authors: Olson John A. 
Published: October 2010

AbstractTwo techniques for obtaining Russell–Saunders term symbols (terms) for equivalent electrons is presented. Both techniques are based on partitioning the n equivalent electrons into a set of α electrons and a set of β electrons. Fundamental tables are presented that give the number of states for the α or β electrons for all possible values M(M) and Sα(Sβ). One interpretation of these tables leads to the total number of states of the n equivalent electrons for values of L and S. From this the number of terms for L and S is easily determined. Another interpretation of the fundamental tables gives the maximum number of terms for n equivalent electrons with values of L and S. From this the actual number of terms is obtained. Examples of equivalent p, d, f, and g electrons are provided. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study on the mechanisms of the nucleophilic substitution reactions of hydrosulfide ion and halomethanes
Authors: He Jianyong , Long Zhengwen , Jing Jian , Zhang Jin‐Sheng 
Published: October 2010

AbstractThree species involved in the nucleophilic substitution reaction of hydrosulfide ion and halomethanes are investigated by ab initio calculations. Geometries for stationary structures along the reaction paths are fully performed with the second‐order Møller–Plesset perturbation approximation with the cc‐pVDZ basis set. The monomer geometries determined by the MP2 method match the experimental results very well. Single point energy calculations are carried out at the coupled cluster with perturbative triple excitations CCSD (T) theory with aug‐cc‐pVDZ basis set. Halomethanes have three conformers here, which lead to the three product channels, HSCH3+ F−1, HSCH3+ Cl−1, and HSCH3+ Br−1. The investigation encompasses the six complexes formed among three channels, respectively. By selecting the six complexes as the model, we investigate the binding energy, topological property of the electron charge density and their Laplacian in detail theoretically. Electrostatic density potential maps of halomethanes are generated for the determination of attractive interaction sites. It is proved that the similar misshaped electron clouds of the three halogen atoms result in the similar properties of the carbon‐halogen bonds, and reveals that the product ion‐dipole complexes interactions are predominantly electrostatic in nature. The calculated results predict the binding energy of the most stable complex in six complexes is −47.06 kcal/mol at the MP2 level of theory. The second channel has the lowest energy barrier, which is −3.63 kcal/mol at the CCSD (T) levels of theory, is expected to be the most important pathway. It occurs via CCl cleavage accompanied by CS bond formation. The other two channels have higher energy barriers and are expected to have smaller rates. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical considerations on the hydrolysis of 2‐dichloromethylbenzimidazole
Authors: Pop Raluca , Medeleanu Mihai , Csunderlik Carol 
Published: October 2010

AbstractHydrolysis reaction of 2‐dichloromethylbenzimidazole with aqueous diethylamine was studied both experimentally and theoretically. The behavior of two other aromatic dihalides (dibromomethylbenzene and 2‐fluoro‐dichloromethylbenzene) was also theoretically studied, starting from already known experimental results. The theoretical calculations of local DFT‐based descriptors (i.e., Fukui function, electrophilicity index) successfully account for the different reactivity of the three aromatic dihalides in the same hydrolysis reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011