bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction period in the low‐temperature thermal oxidation of saturated hydrocarbons: Example of polyethylene
Authors: Richaud Emmanuel , Colin Xavier , Fayolle Bruno , Audouin Ludmila , Verdu Jacques 
Published: October 2008

AbstractThermal oxidation of hydrocarbon substrates at low‐to‐moderate temperature, typically T ≤ 150°C, results from a radical chain process initiated by hydroperoxide decomposition and displays an induction period. A reliable model exists to simulate oxidation kinetics, but an incertitude remains on initial steps because they are out of reach of all available analytical methods. This work is aimed to have a kinetic approach of the problem, by comparing various mechanisms, i.e., (A) bimolecular decomposition of initially present hydroperoxides; (B) combined uni‐ and bimolecular decomposition of hydroperoxides; (C) the presence of radicals at the beginning of the exposure; and (D) radicals generation at (low) constant rate from irradiation, for instance by ionizing radiation linked to natural radioactivity or from a direct oxygen–substrate reaction. Scheme A is not realistic at low initial hydroperoxide concentrations. All the other mechanisms generate similar behaviors: the induction time tends toward a constant value almost independent of the nature of initial steps, when the concentration of precursors (initially present hydroperoxides or radicals) or the rate of their initial production (from species other than hydroperoxides) tends toward zero. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 769–777, 2008
Design Criteria for Accurate Measurement of Bimolecular Radical Termination Rate Coefficients via the RAFT‐CLD‐T Method
Authors: Johnston‐Hall Geoffrey , Barner‐Kowollik Christopher , Monteiro Michael J. 
Published: October 2008

AbstractThe reversible addition‐fragmentation chain transfer chain length dependent termination (RAFT‐CLD‐T) technique allows a simple experimental approach to obtain chain‐length‐dependent termination rate coefficients as a function of conversion, k(x). This work provides a set of criteria by which accurate k(x) can be obtained using the RAFT‐CLD‐T method. Visualization of three‐dimensional plots varying all kinetic rate parameters and starting concentrations demonstrates that only certain combinations give an accurate extraction of k(x). The current study provides hands‐on guidelines for experimentalists applying the RAFT‐CLD‐T method.magnified image
Treatment of restless legs syndrome: An evidence‐based review and implications for clinical practice
Authors: Trenkwalder Claudia , Hening Wayne A. , Montagna Pasquale , Oertel Wolfgang H. , Allen Richard P. , Walters Arthur S. , Costa Joao , Stiasny‐Kolster Karin , Sampaio Cristina 
Published: October 2008

AbstractOnly in the last three decades, the restless legs syndrome (RLS) has been examined in randomized controlled trials. TheMovementDisorder Society (MDS) commissioned a task force to perform an evidence‐based review of the medical literature on treatment modalities used to manage patients with RLS. The task force performed a search of the published literature using electronic databases. The therapeutic efficacy of each drug was classified as being either efficacious, likely efficacious, investigational, nonefficacious, or lacking sufficient evidence to classify. Implications for clinical practice were generated based on the levels of evidence and particular features of each modality, such as adverse events. All studies were classed according to three levels of evidence. All Level‐I trials were included in the efficacy tables; if no Level‐I trials were available then Level‐II trials were included or, in the absence of Level‐II trials, Level‐III studies or case series were included. Only studies published in print or online before December 31, 2006 were included. All studies published after 1996, which attempted to assess RLS augmentation, were reviewed in a separate section. The following drugs are considered efficacious for the treatment of RLS: levodopa, ropinirole, pramipexole, cabergoline, pergolide, and gabapentin. Drugs considered likely efficacious are rotigotine, bromocriptine, oxycodone, carbamazepine, valproic acid, and clonidine. Drugs that are considered investigational are dihydroergocriptine, lisuride, methadone, tramadol, clonazepam, zolpidem, amantadine, and topiramate. Magnesium, folic acid, and exercise are also considered to be investigational. Sumanirole is nonefficacious. Intravenous iron dextran is likely efficacious for the treatment of RLS secondary to end‐stage renal disease and investigational in RLS subjects with normal renal function. The efficacy of oral iron is considered investigational; however, its efficacy appears to depend on the iron status of subjects. Cabergoline and pergolide (and possibly lisuride) require special monitoring due to fibrotic complications including cardiac valvulopathy. Special monitoring is required for several other medications based on clinical concerns: opioids (including, but not limited to, oxycodone, methadone and tramadol), due to possible addiction and respiratory depression, and some anticonvulsants (particularly, carbamazepine and valproic acid), due to systemic toxicities. © 2008 Movement Disorder Society
Moving least‐squares approximation with discontinuous derivative basis functions for shell structures with slope discontinuities
Authors: Zhang Zhiqian , Noguchi Hirohisa , Chen Jiun‐Shyan 
Published: October 2008

AbstractMoving least‐squares approximation with discontinuous derivative basis functions (MLSA‐DBF) is introduced for analysis of shell structures with slope discontinuities. To deal with shells with arbitrary slope discontinuities, the Cartesian coordinate is introduced in the construction of MLSA on the shell surface. The possible causes of singularity in the moment matrix of MLSA on the shell surface with slope discontinuities are identified, and the Moore–Penrose pseudoinverse is used to obtain the generalized inverse of the singular moment matrix resulting from linear dependency and insufficient influence nodes in the MLSA. Following the proposed formulations for shear deformable shell structures with slope discontinuities in the Cartesian coordinates, several numerical examples are analyzed to demonstrate the performance, validity, accuracy, and convergence properties of the proposed MLSA‐DBF approach. Copyright © 2007 John Wiley & Sons, Ltd.
Asymmetric stem cell division and pathology: insights from Drosophila stem cell systems
Authors: Yamashita Y 
Published: October 2008

AbstractAdult stem cells maintain many tissues and organs throughout the life of an organism by serving as renewable sources of differentiated cells. While stem cells remain in a relatively undifferentiated state, their daughters can commit to differentiation to acquire distinct cell fates. Therefore, a stem cell's choice between self‐renewal and commitment to differentiation is of critical importance to the maintenance of functional tissues and organs. Many adult stem cells can divide asymmetrically to produce one self‐renewed stem cell and one differentiated daughter, preserving the critical balance between stem cell and differentiated cell populations. Stem cell dysfunction and/or malfunction have been proposed to lead to several human pathologies, including tumourigenesis and tissue degeneration, yet whether a failure of asymmetric division is a primary cause of stem cell‐related pathologies remains largely uninvestigated. Here, I discuss the implications of asymmetric stem cell division in pathology. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Surgical excision of CNS‐draining lymph nodes reduces relapse severity in chronic‐relapsing experimental autoimmune encephalomyelitis
Authors: van Zwam Marloes , Huizinga Ruth , Heijmans Nicole , van Meurs Marjan , Wierenga‐Wolf Annet F , Melief Marie‐José , Hintzen Rogier Q , 't Hart Bert A , Amor Sandra , Boven Leonie A , Laman Jon D 
Published: October 2008

AbstractDespite lack of classical lymphatic vessels in the central nervous system (CNS), cells and antigens do reach the CNS‐draining lymph nodes. These lymph nodes are specialized to mediate mucosal immune tolerance, but can also generate T‐ and B‐cell immunity. Their role in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE) therefore remains elusive. We hypothesized that drainage of CNS antigens to the CNS‐draining lymph nodes is vital for the recurrent episodes of CNS inflammation. To test this, we surgically removed the superficial cervical lymph nodes, deep cervical lymph nodes, and the lumbar lymph nodes prior to disease induction in three mouse EAE models, representing acute, chronic, and chronic‐relapsing EAE. Excision of the CNS‐draining lymph nodes in chronic‐relapsing EAE reduced and delayed the relapse burden and EAE pathology within the spinal cord, which suggests initiation of CNS antigen‐specific immune responses within the CNS‐draining lymph nodes. Indeed, superficial cervical lymph nodes from EAE‐affected mice demonstrated proliferation against the immunizing peptide, and the deep cervical lymph nodes, lumbar lymph nodes, and spleen demonstrated additional proliferation against other myelin antigen epitopes. This indicates that intermolecular epitope spreading occurs and that CNS antigen‐specific immune responses are differentially generated within the different CNS‐draining lymphoid organs. Proliferation of splenocytes from lymphadenectomized and sham‐operated mice against the immunizing peptide was similar. These data suggest a role for CNS‐draining lymph nodes in the induction of detrimental immune responses in EAE relapses, and conclusively demonstrate that the tolerance‐inducing capability of cervical lymph nodes is not involved in EAE. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Collective dynamics of the ribosomal tunnel revealed by elastic network modeling
Authors: Kurkcuoglu Ozge , Kurkcuoglu Zeynep , Doruker Pemra , Jernigan Robert L. 
Published: October 2008

AbstractThe collective dynamics of the nascent polypeptide exit tunnel are investigated with the computationally efficient elastic network model using normal mode analysis. The calculated normal modes are considered individually and in linear combinations with different coefficients mimicking the phase angles between modes, in order to follow the mechanistic motions of tunnel wall residues. The low frequency fluctuations indicate three distinct regions along the tunnel—the entrance, the neck, and the exit—each having distinctly different domain motions. Generally, the lining of the entrance region moves in the exit direction, with the exit region having significantly larger motions, but in a perpendicular direction, whereas the confined neck region has rotational motions. Especially the universally conserved extensions of ribosomal proteins L4 and L22 located at the narrowest and mechanistically strategic region of tunnel undergo generally anti‐ or non‐correlated motions, which may have an important role in nascent polypeptide gating mechanism. These motions appear to be sufficiently robust so as to be unaffected by the presence of a peptide chain in the tunnel. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Light‐driven rotary molecular motors: an ultrafast optical study
Authors: Augulis Ramūnas , Klok Martin , Feringa Ben L. , Loosdrecht Paul H. M. van 
Published: October 2008

AbstractMolecular rotary motors, though common in nature, were first synthesized rather recently. One of the most promising categories of light‐driven rotary molecular motors which allow for optical control is based on helical overcrowded alkenes. In this category of motors, the rotation of the motor's rotor involves four discrete steps: fast light‐induced cis‐trans isomerisation is followed by a thermally activated step, the same steps are repeated once more to complete the full 360° cycle. Though the rotation rate of the motors is mainly limited by the duration of thermally activated steps, many important factors, such as efficiency and directionality are determined by the light‐induced isomerisation. For the development of ultrafast molecular motors it is crucial to understand the mechanism and dynamics of the optically induced isomerisation steps. In this paper we will review recent time‐resolved optical pump‐probe experiments on chiral molecular motors and discuss the results in terms of potential energy landscapes for the ground and excited states of the motor molecules. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiative decay theory: What suppresses exciton superradiance?
Authors: Bamba Motoaki , Ishihara Hajime 
Published: October 2008

AbstractWe have theoretically studied the exciton superradiance which occurs under a phase‐match between the exciton center‐of‐mass motion and the radiation field in a film with thickness over a light wavelength. With continuously increasing the film thickness, the radiative decay rates of excitons are calculated from extreme values of exciton correlation functions renormalizing the excitonphoton interaction in the film with finite thickness.Due to a consideration of intra‐ and inter‐state retarded interactions, in the simplest system, we have derived the correct suppression thickness of the exciton superradiance. The correctness is verified from the general suppression condition derived from the polariton dispersion relation consisting of complex frequency and wavenumber for finite thickness. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation on stabilities and spectroscopy of C80O2 based on C80 (D5d) using density functional theory
Authors: Ding Yuqi , Gao Peng , Qin Lichao , Teng Qiwen 
Published: October 2008

AbstractThe relative stabilities of the 17 possible isomers for C80O2 based on C80 (D5d) were studied using Becke three parameters plus Lee, Yang, and Parr's (B3LYP) method and 6‐31G (d) basis set in density functional theory. The most stable geometry of C80O2 was predicted to be 23,24,27,28‐C80O2 (A) with annulene‐like structures, where the additive bonds are those between two hexagons (6/6 bonds) near the equatorial belt of C80 (D5d). Electronic spectra of C80O2 isomers were calculated based on the optimized geometries using intermediate neglect of differential overlap (INDO) calculation. Compared with those of C80 (D5d), the first absorptions in the electronic spectra of C80O2 are blue‐shifted owing to the wide energy gaps. 13C nuclear magnetic resonance spectra and nucleus independent chemical shifts of the C80O2 isomers were computed at B3LYP/6‐31G level. The chemical shifts of the bridged carbon atoms in the epoxy structures of C80O2 compared with those of the bridged carbon atoms in the annulene‐like structures are changed upfield. Generally, the isomers with the annulene‐like structures of C80O2 are more aromatic than those with the epoxy structures. The addition of the oxygen atoms near the pole of C80 (D5d) is favorable to improving the aromaticities of C80O2. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
DFT study of the structure and spectral behavior of new pt(II) complexes with 5‐methyl‐5(4‐pyridyl)hydantoin
Authors: Bakalova Adriana , Varbanov Hristo , Stanchev Stancho , Ivanov Darvin , Jensen Frank 
Published: October 2008

AbstractPlatinum complexes are a great interest of study, because of the antitumor activity and the clinical use of some of them in the recent anticancer chemotherapy. In many cases, computational studies can be very useful for predicting the structure and some physicochemical properties of metal complexes. Theoretical calculations can also be used for the rational design of new complexes with optimal ratio: antitumor activity/toxicity. The geometry of three new Pt(II) complexes with general formula cis‐[PtL2X2] (where L is 5‐methyl‐5(4‐pyridyl)hydantoin and X = Cl−, Br−, I−) and of the free organic ligand were optimized using the hybrid DFT method B3LYP with LAN2DZ basis sets. The results were in very good correlation with the data of similar compounds from the literature. The same DFT method was used for the study of their spectral behavior, by reproducing their IR and Raman spectra and comparing them with experimental data. In addition, the distribution of charges by ESP analysis was calculated. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Elemental chains
Authors: Springborg Michael , Dong Yi 
Published: October 2008

AbstractResults of first‐principle density‐functional calculations on isolated, infinite, periodic chains containing only one type of atoms are reported. As examples we consider chains of Se, Al, Ba, Bi, Sb, and Sr. Se represents a material for which chain‐like structures are found naturally, whereas Al prefers structures with high coordinations. Moreover, linear chains have been found in high‐pressure phases of Ba, Bi, Sb, and Sr. For these, the structure of the linear chains is incommensurate with that of the surrounding host. For Se and Al we compare different structures (helical, linear, zigzag, cis, double zigzag, and tetragonal chains), whereas for the other elements we consider only linear chains. Special emphasis is put on structure, relative stability, and band structures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
On the origin of the trans‐influence in square planar d8‐complexes: A theoretical study
Authors: Mitoraj Mariusz P. , Zhu Hongjuan , Michalak Artur , Ziegler Tom 
Published: October 2008

AbstractThe trans influence of ligands T in trans‐[Ni(Cl)2NH3T]n complexes with T−B(Me), H−, CP−, CH2CH, CN−, HCC−, Cl−, F− for n = −1 and TPF3, PH3, P(CH3)3, CO for n = 0 has been analyzed with the help of the extended transition state (ETS) energy decomposition scheme as well as the natural orbitals for chemical valence (NOCV) method. The TCl2NiNH3 bond is made up of the bonding interaction between the empty σNi acceptor orbital on the [TCl2Ni]n fragment and the σNH3 donor orbital. The σNi orbital is in turn an out‐of‐phase combination between d on the metal and an occupied σT orbital: σNi = d − C1 × σT. It is shown that the trans influence is related to the contribution (C1) to σNi from σT. Thus, the smaller the contribution C1 to σNi the larger the <σNi|σNH3> overlap and the stronger the TCl2NiNH3 bond. The contribution C1 is in turn related to the orbital energy ε(σT) of T. Thus the lower ε(σT) is, the smaller is C1. There is thus an inverse relation between the trans influence of a ligand T and its electronegativity. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Application of passive soil gas technology to determine the source and extent of a PCE groundwater plume in an urban environment
Authors: Clarke James N. , Goodwin Deborah F. , O'Neill Harry , Odencrantz Joseph E. 
Published: October 2008

AbstractIn situations where groundwater supplies have been impacted by volatile organic compounds (VOCs), such as tetrachloroethene (PCE), and the source has not been identified, the costs to identify the source and plume migration patterns may be extremely high. The costs for an investigation increase with the number and depth of borings and the number of samples that are collected and analyzed. An environmental investigator and the Arizona Department of Environmental Quality (ADEQ) have successfully utilized passive soil gas (PSG) surveys in Arizona to cost‐effectively investigate VOC impacts to groundwater and identify potential sources of impact. PSG surveys are minimally intrusive, and more samples can be collected for the same cost when compared to active soil gas surveys and conventional soil and groundwater sampling programs. The result is a surficial representation of the contaminant plume and the location of “hot spots,'' which are the potential sources. This provides a better understanding of the nature and extent of the impact and allows for a focused subsurface investigation, which subsequently reduces drilling and sampling costs. © 2008 Wiley Periodicals, Inc.
Rethinking the notion of technology in education: Techno‐epistemology as a feature inherent to human praxis
Authors: Eijck Michiel Van , Claxton Nicholas Xumthoult 
Published: October 2008

AbstractEducators repeatedly underscore the intimate relationship between science and technology. This is problematic because technology, far from being “applied science,” presupposes a unique epistemology (techno‐epistemology). A focus on the role of science in technology overshadows this unique way of knowing and hence limits technology education and privileges a scientific worldview in education. To appropriately frame the unique epistemology of technology in education, we propose a cognitive framework developed to understand the use and development of tools in human activity, namely, Cultural‐Historical Activity Theory (CHAT). Drawing on a case study of technology that is not rooted in a (Eurocentric) scientific tradition, the SXOLE (Reef Net) fishing technology of theWSÁNEĆ (Saanich) people, we show how technology can be understood as inherent to human praxis, which presupposes a dialectically related and unique epistemology that is incommensurable and irreducible to a scientific worldview. The implications of this framework for science and technology education are discussed. © 2008 Wiley Periodicals, Inc.Sci Ed93:218–232, 2009
Thresholds for the formation of satellites in two-dimensional vortices
Authors: TURNER M. R. , GILBERT A. D. 
Published: October 2008

This paper examines the evolution of a two-dimensional vortex which initially consists of an axisymmetric monopole vortex with a perturbation of azimuthal wavenumber m = 2 added to it. If the perturbation is weak, then the vortex returns to an axisymmetric state and the non-zero Fourier harmonics generated by the perturbation decay to zero. However, if a finite perturbation threshold is exceeded, then a persistent nonlinear vortex structure is formed. This structure consists of a coherent vortex core with two satellites rotating around it.The paper considers the formation of these satellites by taking an asymptotic limit in which a compact vortex is surrounded by a weak skirt of vorticity. The resulting equations match the behaviour of a normal mode riding on the vortex with the evolution of fine-scale vorticity in a critical layer inside the skirt. Three estimates of inviscid thresholds for the formation of satellites are computed and compared: two estimates use qualitative diagnostics, the appearance of an inflection point or neutral mode in the mean profile. The other is determined quantitatively by solving the normal mode/critical-layer equations numerically. These calculations are supported by simulations of the full Navier–Stokes equations using a family of profiles based on the tanh function.
Protective efficacy of a filarial surface antigen in experimental filariasis
Authors: Mandal N.N. , Bal M.S. , Das M.K. , Beuria M.K. 
Published: October 2008

AbstractA water-insoluble, detergent-soluble, surface-associated glycoprotein, designated as Dssd1, was found to induce microfilaria clearance inMastomys couchaimplanted withSetaria digitata. Intraperitoneal implantation of adult female worms ofS. digitatainM. couchacould induce microfilaraemia lasting about 165 days in circulation. Immunization ofM. couchawith Dssd1 antigen either before or after implantation of worms resulted in a significant reduction in microfilaria density. Complete clearance of circulating microfilaria was achieved by immunization (before and after implantation) in animals by 95 and 105 days post-implantation, respectively, indicating the efficacy of Dssd1 antigen in the clearance of microfilaraemia in infectedM. coucha.