bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal maintenance strategy for Technology‐enhanced classrooms: a case study
Authors: Lawson John S. , Manortey Stephen 
Published: July 2009

AbstractThe purpose of the study was to collect data and evaluate an age‐based bulb replacement policy for projectors used in Technology‐enhanced classrooms in a university campus.The Office of Information Technology (OIT) had instituted a policy to replace bulbs in these projectors after either failure or 1800h of operation without failure. However, databases maintained by OIT included the time to bulb failure, the average number of times the bulbs were turned on and off per week, and the number of thermal events. Modeling the failure data with a Weibull proportional hazards model revealed that probability of bulb failure was a function of the number of hours a bulb was used and the frequency at which it was turned on and off. Combining this information with a cost model led to the recommendation for an improved condition‐based replacement policy. Copyright © 2009 John Wiley & Sons, Ltd.
Planck–Benzinger thermal work function: Monoclonal antibody–DNA duplex binding interactions
Authors: Chun Paul W. 
Published: July 2009

AbstractWe have reexamined the van't Hoff plots and delineation of thermodynamic data of the monoclonal antibodies of Jel 274 and Jel 241 binding to DNA duplex at high ionic strength using fluorescein‐labeled oligonucleotide titration with increasing concentrations of the antibody as reported by Tanha and Lee (Nucleic Acid Res, 1997, 25, 1442). To compare the thermodynamic parameters from data over the experimental temperature range of 277–312.5 K, the binding constant from van't Hoff plots is used to evaluate ΔGo(T) from 0 to 400 K using our general linear T3 model, ΔGo(T) = α +βT2+γT3. The limited information provided by the van't Hoff plots and their extensions is not sufficient to describe the variations in the Gibbs free energy change as a function of temperature and other thermodynamic functions observed in these and other biological interactions. Rather, it is necessary to determine a number of thermodynamic parameters, including the heat of reaction, (Th), (Tm), and (TCp), and the thermal set point, (TS), all of which can be precisely assessed using our general linear T3 model. To date, no experimental measurement offers this degree of accuracy. In evaluating the thermodynamic parameters in the binding interaction of monoclonal IgG Jel 241–d[AT]20DNA duplex, it is apparent that at a high NaCl concentration, the range of the compensatory temperatures, (Th) = 155 K and (Tm) = 450 K, is much broader than observed in any other sample, whereas the thermal set points, (TS) = 330 K, is 20–30 K higher. The inherent chemical bond energy ΔHo(T0) is much lower in this sample. The values of thermal agitation energy (heat capacity integrals) are of similar magnitude for all the samples tested. It appears that increasing the NaCl concentration to 130 mM will greatly enhance the binding interaction between the monoclonal antibody and DNA duplex. It is not clear, however, from the limited data available, whether the binding interaction is sequence specific, although logic would suggest it is. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A DFT study of two diiron (II) synthetic model compounds and their diiron(III) peroxide oxygenation products
Authors: Binning R. C. , Bacelo Daniel E. 
Published: July 2009

AbstractUnrestricted density functional theory calculations have been conducted on two diiron(II) synthetic model compounds. Calculations employed the BPW91 and BOP density functionals with both high‐spin and broken symmetry low‐spin representations of weakly coupled high‐spin irons. Comparison of the calculated and crystallographic structures is made, and good agreement is found with both spin representations. Raman spectral data are available for the diiron(III) product of the reaction with O2 to form a bridged peroxide. Calculated harmonic frequencies confirm the experimental assignments. Small geometry differences between the high spin and broken symmetry results are seen in bond lengths, angles, Raman frequencies, and spin densities associated with oxo and peroxo bridges in the diiron(III) oxidation products. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Pt adsorption on the PbTiO3(110) polar surface: a density functional theory study
Authors: Pang Qing , Zhang Jian‐Min , Xu Ke‐Wei , Ji Vincent 
Published: July 2009

AbstractThe monolayer (ML) and submonolayer Pt on both terminations of PbTiO3(110) polar surface have been studied by using density functional theory (DFT) with projector‐augmented wave(PAW) potential and a supercell approach. The most favored ML Pt arrangements on PbTiO and O2terminations are the hollow site and the short‐bridge site, respectively. By examining the geometries of different ML arrangements, we know that the dominant impetus for stability of the favored adsorption site for PbTiO termination is the Pt–Ti interaction (mainly from covalent bonding), while that for O2termination is the Pt–O interaction (mainly from ionic bonding). In addition, the appearance of the gap electronic states in the outermost layers of each termination indicates that a channel for charge transfer between adsorbed layer and substrate is formed. Moreover, the interface hybridization between Pt 5d and O 2p orbitals is also observed, especially for ML Pt on O2termination. The stability sequences for various arrangements of 1/2 ML Pt adsorption conform well with those of ML Pt adsorption, and the most stable arrangement is energetically more favorable than the corresponding ML coverage in the view of adsorption energy maximization. The behavior, i.e. the increase in adsorption energy with decrease in coverage, indicates that PtPt interactions weaken those between Pt and the substrate. Copyright © 2009 John Wiley & Sons, Ltd.
Gold Nanoparticles of Diameter 1.4 nm Trigger Necrosis by Oxidative Stress and Mitochondrial Damage
Authors: Pan Yu , Leifert Annika , Ruau David , Neuss Sabine , Bornemann Jörg , Schmid Günter , Brandau Wolfgang , Simon Ulrich , Jahnen‐Dechent Willi 
Published: July 2009

AbstractGold nanoparticles (AuNPs) are generally considered nontoxic, similar to bulk gold, which is inert and biocompatible. AuNPs of diameter 1.4 nm capped with triphenylphosphine monosulfonate (TPPMS), Au1.4MS, are much more cytotoxic than 15‐nm nanoparticles (Au15MS) of similar chemical composition. Here, major cell‐death pathways are studied and it is determined that the cytotoxicity is caused by oxidative stress. Indicators of oxidative stress, reactive oxygen species (ROS), mitochondrial potential and integrity, and mitochondrial substrate reduction are all compromised. Genome‐wide expression profiling using DNA gene arrays indicates robust upregulation of stress‐related genes after 6 and 12 h of incubation with a 2 × IC50 concentration of Au1.4MS but not with Au15MS nanoparticles. The caspase inhibitor Z‐VAD‐fmk does not rescue the cells, which suggests that necrosis, not apoptosis, is the predominant pathway at this concentration. Pretreatment of the nanoparticles with reducing agents/antioxidants N‐acetylcysteine, glutathione, and TPPMS reduces the toxicity of Au1.4MS. AuNPs of similar size but capped with glutathione (Au1.1GSH) likewise do not induce oxidative stress. Besides the size dependency of AuNP toxicity, ligand chemistry is a critical parameter determining the degree of cytotoxicity. AuNP exposure most likely causes oxidative stress that is amplified by mitochondrial damage. Au1.4MS nanoparticle cytotoxicity is associated with oxidative stress, endogenous ROS production, and depletion of the intracellular antioxidant pool.
Wrapping Nanotubes with Micelles, Hemimicelles, and Cylindrical Micelles
Authors: Calvaresi Matteo , Dallavalle Marco , Zerbetto Francesco 
Published: July 2009

AbstractThis work uses a simple model based on hydrophobic and hydrophilic forces to investigate the molecular dynamics that lead to the supramolecular self‐assembly of surfactants around carbon nanotubes (CNTs). The effects of the concentration and the structure of surfactants are explored. The bead‐based mesoscopic description spontaneously develops the several micellar morphologies that are known to wrap and solvate CNTs.
Bimetallic Nanostructures as Active Raman Markers: Gold‐Nanoparticle Assembly on 1D and 2D Silver Nanostructure Surfaces
Authors: Gunawidjaja Ray , Kharlampieva Eugenia , Choi Ikjun , Tsukruk Vladimir V. 
Published: July 2009

AbstractIt is demonstrated that bimetallic silver–gold anisotropic nanostructures can be easily assembled from various nanoparticle building blocks with well‐defined geometries by means of electrostatic interactions. One‐dimensional (1D) silver nanowires, two‐dimensional (2D) silver nanoplates, and spherical gold nanoparticles are used as representative building blocks for bottom‐up assembly. The gold nanoparticles are electrostatically bound onto the 1D silver nanowires and the 2D silver nanoplates to give bimetallic nanostructures. The unique feature of the resulting nanostructures is the particle‐to‐particle interaction that subjects absorbed analytes to an enhanced electromagnetic field with strong polarization dependence. The Raman activity of the bimetallic nanostructures is compared with that of the individual nanoparticle blocks by using rhodamine 6G solution as the model analyte. The Raman intensity of the best‐performing silver–gold nanostructure is comparable with the dense array of silver nanowires and silver nanoplates that were prepared by means of the Langmuir–Blodgett technique. An optimized design of a single‐nanostructure substrate for surface‐enhanced Raman spectroscopy (SERS), based on a wet‐assembly technique proposed here, can serve as a compact and low‐cost alternative to fabricated nanoparticle arrays.
Formation of Single Tiers of Bridging Silicon Nanowires for Transistor Applications Using Vapor–Liquid–Solid Growth from Short Silicon‐on‐Insulator Sidewalls
Authors: Nayfeh Osama M. , Antoniadis Dimitri A. , Boles Steven , Ho Charles , Thompson Carl V. 
Published: July 2009

AbstractSingle tiers of silicon nanowires that bridge the gap between the short sidewalls of silicon‐on‐insulator (SOI) source/drain pads are formed. The formation of a single tier of bridging nanowires is enabled by the attachment of a single tier of Au catalyst nanoparticles to short SOI sidewalls and the subsequent growth of epitaxial nanowires via the vapor–liquid–solid (VLS) process. The growth of unobstructed nanowire material occurs due to the attachment of catalyst nanoparticles on silicon surfaces and the removal of catalyst nanoparticles from the SOI‐buried oxide (BOX). Three‐terminal current–voltage measurements of the structure using the substrate as a planar backgate after VLS nanowire growth reveal transistor behaviour characteristics.
GABAA‐benzodiazepine receptor availability in smokers and nonsmokers: Relationship to subsyndromal anxiety and depression
Authors: Esterlis Irina , Cosgrove Kelly P. , Batis Jeffery C. , Bois Frederic , Kloczynski Tracy A. , Stiklus Stephanie M. , Perry Edward , Tamagnan Gilles D. , Seibyl John P. , Makuch Robert , Krishnan‐Sarin Suchitra , O'Malley Stephanie , Staley Julie K. 
Published: July 2009

AbstractMany smokers experience subsyndromal anxiety symptoms while smoking and during acute abstinence, which may contribute to relapse. We hypothesized that cortical gamma aminobutyric acidA‐benzodiazepine receptor (GABAA‐BZR) availability in smokers and nonsmokers might be related to the expression of subsyndromal anxiety, depressive, and pain symptoms. Cortical GABAA‐BZRs were imaged in 15 smokers (8 men and 7 women), and 15 healthy age and sex‐matched nonsmokers, and 4 abstinent tobacco smokers (3 men; 1 woman) using [123I]iomazenil and single photon emission computed tomography (SPECT). Anxiety and depressive symptoms were measured using the Spielberger's State‐Trait Anxiety Index (STAI) and the Center for Epidemiology Scale for Depressive Symptoms (CES‐D). The cold pressor task was administered to assess pain tolerance and sensitivity. The relationship between cortical GABAA‐BZR availability, smoking status, and subsyndromal depression and anxiety symptoms, as well as pain tolerance and sensitivity, were evaluated. Surprisingly, there were no statistically significant differences in overall GABAA‐BZR availability between smokers and nonsmokers or between active and abstinent smokers; however, cortical GABAA‐BZR availability negatively correlated with subsyndromal state anxiety symptoms in nonsmokers but not in smokers. In nonsmokers, the correlation was seen across many brain areas with state anxiety [parietal (r= −0.47,P= 0.03), frontal (r= −0.46,P= 0.03), anterior cingulate (r= −0.47,P= 0.04), temporal (r= −0.47,P= 0.03), occipital (r= −0.43,P= 0.05) cortices, and cerebellum (r= −0.46,P= 0.04)], trait anxiety [parietal (r= −0.72,P= 0.02), frontal (r= −0.72,P= 0.02), and occipital (r= −0.65,P= 0.04) cortices] and depressive symptoms [parietal (r= −0.68;P= 0.02), frontal (r= −0.65;P= 0.03), anterior cingulate (r= −0.61;P= 0.04), and temporal (r= −0.66;P= 0.02) cortices]. The finding that a similar relationship between GABAA‐BZR availability and anxiety symptoms was not observed in smokers suggests that there is a difference in GABAA‐BZR function, but not number, in smokers. Thus, while subsyndromal anxiety and depressive symptoms in nonsmokers may be determined in part by GABAA‐BZR availability, smoking disrupts this relationship. Aberrant regulation of GABAA‐BZR function in vulnerable smokers may explain why some smokers experience subsyndromal anxiety and depression. Synapse 63:1089–1099, 2009. © 2009 Wiley‐Liss, Inc.
Increased cortical nitric oxide release after phencyclidine administration
Authors: Pålsson Erik , Finnerty Niall , Fejgin Kim , Klamer Daniel , Wass Caroline , Svensson Lennart , Lowry John 
Published: July 2009

AbstractPhencyclidine exerts psychotomimetic effects in humans and is used as a pharmacological animal model for schizophrenia. We, and others, have demonstrated that phencyclidine induces cognitive deficits in rats that are associated with schizophrenia. These cognitive deficits can be normalized by inhibition of nitric oxide synthase. The development of selective microelectrochemical nitric oxide sensors may provide direct evidence for the involvement of nitric oxide in these effects. The aim of the present study was to use LIVE (long term in vivo electrochemistry) to investigate the effect of phencyclidine, alone or in combination with the nitric oxide synthase inhibitor L‐NAME, on nitric oxide levels in the medial prefrontal cortex of freely moving rats. Phencyclidine (2 mg kg−1) produced an increase in cortical nitric oxide levels and this increase was ameliorated by L‐NAME (10 mg kg−1). Tentatively, the results from the present study provide a biochemical rationale for the involvement of nitric oxide in the phencyclidine model of schizophrenia. Synapse 63:1083–1088, 2009. © 2009 Wiley‐Liss, Inc.
Investigating teacher learning supports in high school biology curricular programs to inform the design of educative curriculum materials
Authors: Beyer Carrie J. , Delgado Cesar , Davis Elizabeth A. , Krajcik Joseph 
Published: July 2009

AbstractReform efforts have emphasized the need to support teachers' learning about reform‐oriented practices. Educative curriculum materials are one potential vehicle for promoting teacher learning about these practices. Educative curriculum materials include supports that are intended to promote both student and teacher learning. However, little is known about the extent to which existing curriculum materials provide support for teachers and the ways they can be improved. In this study, eight sets of high school biology curriculum materials were reviewed to determine their potential for promoting teacher learning. Design heuristics for educative curriculum materials were adapted for use as evaluation criteria. From this analysis, several themes emerged. First, the materials tended to provide support for teachers' subject matter knowledge and pedagogical content knowledge for students' ideas (e.g., misconceptions) but rarely for their pedagogical content knowledge of scientific inquiry. Second, the materials contained several implementation guidance supports but far fewer rationales for instructional decisions, which are an important feature of educative curriculum materials. Finally, the quality of support varied widely, differing in its degree of relevance, pedagogical helpfulness, and depth. The article concludes with recommendations for the redesign of existing curriculum materials. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 977–998, 2009
Conjugate gradient method
Authors: Nazareth J. L. 
Published: July 2009

AbstractThe conjugate gradient (CG) method for optimization and equation solving is described, along with three principal families of algorithms derived from it. In each case, a foundational CG algorithm is formulated mathematically and followed by a brief discussion of refinements and variants within its family. The hierarchical nature of the subject matter is highlighted, because each foundational CG algorithm presented is a descendant of one earlier in the list from which it inherits fundamental algorithmic properties. Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Algorithms and Computational Methods > Numerical Methods
Metastasis of Right Upper Para‐Esophageal Lymph Nodes in Central Compartment Lymph Node Dissection of Papillary Thyroid Cancer
Authors: Lee Byung‐Joo , Lee Jin‐Choon , Wang Soo‐Geun , Kim Yong‐Ki , Kim In‐Ju , Son Seok‐Man 
Published: July 2009

AbstractBackgroundAlthough some lymph nodes (upper para‐esophageal lymph nodes) that exist between the right recurrent laryngeal nerve and the esophagus should be involved in central‐compartment lymph node dissection (CLND) in patients with papillary thyroid cancer, the procedure can cause some injury to the nerve. We set out to assess the incidence of right upper para‐esophageal lymph node metastasis after routine CLND.MethodsRecords from 123 patients with PTC who underwent total thyroidectomy with CLND were reviewed.ResultsFourteen of 123 patients exhibited nodal metastasis in right upper para‐esophageal lymph nodes. Metastasis of right upper para‐esophageal lymph nodes was usually associated with lesions of the right thyroid, comparatively large tumor size (more than 1 cm), and lateral cervical lymph node metastasis (p < 0.05).ConclusionsRight upper para‐esophageal lymph nodes should be removed during operation for PTC in patients with lesions of the right thyroid gland, large tumor size, and lateral cervical lymph node metastasis.
Significance of Controlling Chronic Proliferative Cholangitis in the Treatment of Hepatolithiasis
Authors: Li Fu Yu , Cheng Nan Sheng , Mao Hui , Jiang Li Sheng , Cheng Jing Qiu , Li Quan Sheng , Munireddy Sanjay 
Published: July 2009

AbstractBackgroundRecently, high stone recurrence and biliary restenosis rates in hepatolithiasis patients have been confirmed to be closely related to chronic proliferative cholangitis (CPC). However, the effective management of CPC has not yet been established.Methods and resultsA vicious cycle exists between the presence of intrahepatic calculi and CPC: both the stone itself and secondary biliary infection can stimulate persistent hyperplasia in the biliary duct wall, leading to the occurrence of CPC and biliary stricture. The recurrent attacks of CPC will, in turn, facilitate new stone formation via mucoglycoprotein production, or induced biliary stricture and cholestasis. Thus, even when the stone is completely removed and the biliary tract stenosis is corrected, residual CPC will persist and progress, with an underlying risk for postoperative stone recurrence and biliary tract restenosis. Therefore, the perfect hepatolithiasis treatment would target stone removal and correction of the biliary tract stricture, as well as control of postoperative residual CPC. In fact, CPC, the management of which has been traditionally ignored, is the key to breaking this vicious cycle.ConclusionsOverall, the subsequent treatment of residual CPC after operation or choledochoscopic lithotomy would be helpful to decrease postoperative stone recurrence and the rate of biliary restenosis. Adding such treatment would reduce the incidence of surgical reintervention and choledochoscopic lithotomy, and it would also improve the postoperative hepatolithiasis outlook.
Fragiles-X Syndrom
Authors: Steinbach P. 
Published: July 2009

Zusammenfassung
Fragiles-X Syndrom, eine X-chromosomal vererbte neuronale Entwicklungsstörung, betrifft Knaben und Mädchen. Phänotypisch charakteristisch sind intellektuelle Defizite, somatische Merkmale und Verhaltensauffälligkeiten. Pathophysiologisch liegt der Verlust des Proteins FMRP („fragile X mental retardation protein“) zugrunde, in dessen Folge es zum Untergang von Synapsen mit metabotropen Glutamatrezeptoren kommt. Das Gen FMR1 („fragile X mental retardation 1“) enthält in der 5’-nichttranslatierten Genregion eine CGG-Wiederholungssequenz (CGG-Repeat). Bei fast allen Patienten mit Fragilem-X Syndrom liegt ein vollmutiertes, meist inaktives FMR1 mit >200 CGG-Repeats vor. Vollmutationen entstehen bei der Oogonienvermehrung im fetalen Ovar von Trägerinnen eines mitotisch instabilen Prämutationsallels (59–200 Repeats). Die Prämutation führt nicht zu Symptomen des Fragilen-X Syndroms, ist aber ein Risikofaktor für vorzeitige Ovarialinsuffienz und/oder fragiles X-assoziiertes Tremor/Ataxie Syndrom. Die Diagnostik beider Syndrome erfordert eine genetische Untersuchung zur Bestimmung der FMR1-CGG-Repeats. Die vorgeburtliche Diagnostik kann von allen Frauen mit prä- oder vollmutiertem Gen beansprucht werden.
Geistige Behinderung infolge Stoffwechselkrankheit
Authors: Moog U. , Hoffmann G.F. , Zschocke J. 
Published: July 2009

Zusammenfassung
Angeborene Stoffwechselerkrankungen („inborn errors of metabolism“, IEM) sind seltene Ursachen einer geistiger Behinderung (GB) und finden sich in etwa 1% der GB-Fälle der kaukasischen Bevölkerung. Im Gegensatz zu den Empfehlungen für andere diagnostische Tests bei der Abklärung von GB, z. B. einer Chromosomenanalyse, besteht kein Konsens bezüglich der Stoffwechseldiagnostik. IEM sind jedoch potenziell behandelbar, und ihre Diagnose ist bei den Betroffenen für die Prognose, das Wiederholungsrisiko und die Möglichkeiten der Pränataldiagnostik von großer Bedeutung. Aufgrund der aktuell vorliegenden Evidenz lassen sich folgende wichtige IEM hervorheben, die zu unspezifischer GB oder zu Krankheitsbildern mit GB als Hauptmerkmal führen können: Kreatinmangelsyndrome (v. a. Kreatintransportermangel), Mukopolysaccharidose III (v. a. IIIB), β-Mannosidose, einige Organazidopathien, Homozystinurie, angeborene Glykosylierungsstörungen (CDG, „congenital disorders of glycosylation“) und spezifische Störungen des Purin- und Pyrimidinstoffwechsels. Außerdem kommen Harnstoffzyklusdefekte, Sterolsynthesedefekte und weitere Aminoazidurien in Betracht. Die entsprechende Stoffwechseldiagnostik bei ungeklärter GB wird vorgestellt.
Syndromale Formen geistiger Behinderung
Authors: Gillessen-Kaesbach G. 
Published: July 2009

Zusammenfassung
Die geistige Behinderung bei syndromalen Krankheitsbildern kann sehr verschieden stark ausgeprägt sein. Auch können Betroffene mit dem gleichen Syndrom einen unterschiedlichen Schweregrad der geistigen Behinderung aufweisen. Die Diagnosestellung stellt eine große Herausforderung für den klinischen Genetiker dar, insbesondere wegen der unterschiedlichen phänotypischen Ausprägung. Neben einer exakten Erhebung der Familienanamnese und der körperlichen Befunde ist die Beachtung von Leitsymptomen wie Adipositas, Makrosomie, Mikrozephalie, prä- oder postnatalem Kleinwuchs oder spezifischer Fehlbildungsmuster hilfreich bei der klinischen Diagnostik. Die modernen zytogenetischen und molekularzytogenetischen Diagnostiken wie CGH-Array (CGH: „comparative genomic hybridization“) tragen dazu bei, eine ätiologische Klärung herbeizuführen und Krankheitsentitäten zu definieren.