bluuebunny/crossref_metadata_2025_split huggingface dataset:
The kinetic and biological activity of different loaded rhBMP‐2 calcium phosphate cement implants in rats
Authors: Bodde Esther W. H. , Boerman Otto C. , Russel Frans G. M. , Mikos Antonios G. , Spauwen Paul H. M. , Jansen John A. 
Published: January 2008

AbstractThe healing of large bone defects can be improved by osteogenic bone graft substitutes, due to growth factor inclusion. A sustained release of these growth factors provides more efficient bioactivity when compared with burst release and might reduce the dose required for bone regeneration, which is desirable for socioeconomical and safety reasons. In this study, we compared different rhBMP‐2 loadings in a sustained release system of CaP cement and PLGA‐microparticles and were able to couple kinetic to biological activity data. Fifty‐two rats received a critical‐size cranial defect, which was left open or filled with the cement composites. The implants consisted of plain, high, and five‐fold lower dose rhBMP‐2 groups. Implantation time was 4 and 12 weeks. Longitudinal in vivo release was monitored by scintigraphic imaging of 131I‐labeled rhBMP‐2. Quantitative analysis of the scintigraphic images revealed a sustained release of 131I‐rhBMP‐2 for both doses, with different release profiles between the two loadings. However, around 70% of the initial dose was retained in both implant formulations. Although low amounts of rhBMP‐2 were released (2.4 ± 0.8 μg in 5 weeks), histology showed defect bridging in the high‐dose implants. Release out of the low‐dose implants was not sufficient to enhance bone formation. Implant degradation was limited in all formulations, but was mainly seen in the high‐dose group. Low amounts of sustained released rhBMP‐2 were sufficient to bridge critically sized defects. A substantial amount of rhBMP‐2 was retained in the implants because of the slow release rate and the limited degradation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Interaction‐induced temperature‐dependent switching of the phase of commensurability oscillations in a one‐dimensional lateral superlattice
Authors: Mitzkus Christian , Wegscheider Werner , Umanski Vladimir , Eberl Karl , Weiss Dieter 
Published: January 2008

AbstractWe study magnetotransport of a two‐dimensional electron system (2DES) in the presence of an additional one‐dimensional potential modulation. The commensurability oscillations observed in such a density modulated 2DES show a temperature dependent switching of their phase in the case when the modulation pattern is orientated parallel to the current. This behavior is compared with a recent theory on the consequences of electron electron interaction by Gornyi and Mirlin [Phys. Rev. B 69, 45313, (2004)]. The theory predicts a temperature dependent mixing of the components of the resistivity tensor, which explains the phase switching as an overlapping of two kinds of commensurability oscillations. Good qualitative agreement between experiment and theory is found. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The quantum Hall effect in narrow quantum wires
Authors: Struck A. , Kawarabayashi T. , Zhuravlev A. , Ohtsuki T. , Kramer B. , Kettemann S. 
Published: January 2008

AbstractThe quantum phase diagram of disordered quantum wires in a strong magnetic field is reviewed. For uncorrelated disorder potential the 2‐terminal conductance, as calculated with the numerical transfer matrix method, shows zero temperature discontinuous transitions between exactly integer plateau values and zero. This is explained by the dimensional crossover of the bulk localisation length, which drives a transition from delocalised to localised edge states. In the thermodynamic limit, fixing the aspect ratio of the wire, there is a transition from the one dimensional chiral metal of extended edge states to localisation along the wire. In the vicinity of this chiral metal insulator transition (CMIT), states are identified which are superpositions of edge states with opposite chirality. The bulk contribution of such states is found to decrease with increasing wire width. Based on exact diagonalisation results for the eigenstates and their participation ratios, we conclude that these states are characteristic for the CMIT, and have the appearance of nonchiral edges states. Thereby these states are distinguishable from other states in the quantum Hall wire, namely, extended edge states, two‐dimensionally (2D) localized, quasi‐1D localized, and 2D critical states. In the presence of spatially correlated random potential we find with the numerical transfermatrix method that the potential correlation results in a shift of quantized conductance plateaus in long wires proportional to the strength of the random potential. This shift is found to be insensitive to the strength of magnetic fields and the same for all plateaus. A semiclassical explanation of this effect is proposed. We conclude with an outlook on modfications of the quantum phase diagram due to the spin degree of freedom of the electrons and their interactions. We discuss the stability of the phase diagram at finite temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of screening on current distribution and conductance quantisation in narrow quantum Hall systems
Authors: Gerhardts Rolf R. 
Published: January 2008

AbstractWe summarize and critically discuss the screening theory of the integer quantized Hall effect (IQHE), which was recently developed in order to understand scanning‐force‐microscope experiments on the current distribution in narrow Hall bars. The theory is based on the combination of a self‐consistent, non‐linear screening theory with a linear, local transport theory. In addition to the explanation of the mentioned experiments, it allows a simple understanding of the IQHE, including the enormous reproducibility of the measured quantized resistance values. Both achievements result from two key mechanisms: The first, which follows from the screening theory, is the existence of incompressible strips, with integer values of the local Landau level filling factor and quantized values of longitudinal and Hall resistivity, in certain magnetic field intervals. The second, a result of the local transport theory, is the confinement of an imposed dissipative current to these strips. This confinement leads to the quantization of the global resistances, without any localization assumptions. We also discuss limitations and possible extensions as well as further applications of this theory. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phonon and transport measurements in the fractional quantum Hall effect
Authors: Schulze‐Wischeler Fritz , Dethlefsen Annelene F. , Hohls Frank , Zeitler Uli , Haug Rolf J. 
Published: January 2008

AbstractThe properties of a fractional quantum Hall system has been investigated with phonon experiments and with transport experiments. A detailed description of the phonon absorption technique is given. We measure the relative specific heat in the fractional quantum Hall effect regime at various filling factors. We use phonons to measure the activation gap Δ of the fractional quantum Hall states at constant fillings as a function of the perpendicular magnetic field B. At a given filling factor nearly all gaps measured show a square‐root dependence on the magnetic field and can be described by one single fit parameter related to the composite fermion effective mass. In addition, we present transport experiments to deduce energy gaps. Here, an astonish linear dependence of Δ on B is observed for a number of fractional filling factors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sharp quantum Hall edges: Experimental realizations of edge states without incompressible strips
Authors: Grayson Matthew , Steinke Lucia , Huber Michael , Schuh Dieter , Bichler Max , Abstreiter Gerhard 
Published: January 2008

AbstractExperimental results of sharp edge potentials in the quantum Hall (QH) regime of a two‐dimensional electron system are presented. First the general QH edge state picture is reviewed, including recent theory which explains the importance of incompressible strips at the sample edge. Then two sharp edge geometries are presented where incompressible strips are predicted to vanish below the scale of the magnetic length: T ‐junction edge tunneling devices and L ‐junction bent quantum wells. Tunnel spectroscopy in the T ‐junction device directly measures the real space position of the edge state orbit centers, verifying an almost ideal sharp edge confinement and providing evidence that incompressible strips vanish in such a potential. Conduction along the junction of the L ‐sample is presented, revealing unconventional temperature and voltage dependence along a unique type of QH boundary. Hartree calculations explain how this behavior can result from the sharp non‐planar confinement potential which is not possible to realize either in planar systems or at soft‐confinement boundaries. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Review of Literature‐Based Quantitative Structure–Activity Relationship Models for Bioconcentration
Authors: Pavan Manuela , Netzeva Tatiana I. , Worth Andrew P. 
Published: January 2008

AbstractThis paper reviews the state of the art of in silico methods for assessing the tendency of a substance to bioconcentrate in aquatic organisms usually expressed as its Bioconcentration Factor (BCF). It is based on an in‐depth review performed by the European Chemicals Bureau of the European Commission's Joint Research Centre in support of the development of technical guidance for the implementation of the REACH legislation, and is one of a series of minireviews in this journal. The most widely used in silico approaches to estimate BCF are described, with emphasis on literature‐based (Quantitative) Structure‐Activity Relationship [(Q)SAR] models: (1) linear relationships that correlate the BCF with octanol–water partition coefficient; (2) (Q)SAR models based on experimentally derived descriptors and (3) new (Q)SAR models aimed to evaluate the potential of other descriptors. Recommendations for further research are also provided.
(Q)SARs for Predicting Effects Relating to Reproductive Toxicity
Authors: Cronin Mark T. D. , Worth Andrew P. 
Published: January 2008

AbstractThis paper reviews the current status of structure‐based methods for predicting adverse reproductive effects in mammals. The methods described include (Quantitative) Structure–Activity Relationships ((Q)SARs), expert systems and the less formalised approaches of read‐across within (chemical) categories. There are a number of problems with applying QSARs to reproductive toxicology notably the complexity, subtlety and sometimes ill‐defined nature of the endpoints and lack of data available for modelling. A small number of ((Q)SARs have been developed for individual classes of compounds for well‐defined effects. These are supplemented by expert systems approaches of all types [e.g. DEREK for Windows, TOPKAT, MC4PC, PASS, Organisation for Economic Co‐operation and Development (OECD) QSAR Application Toolbox] for a variety of endpoints associated with reproductive toxicology. By far the largest, and best developed, group of models are those for receptor binding effects related to endocrine disruption, in particular to the Oestrogen Receptor (ER) and, to a lesser extent, the Androgen Receptor (AR). Strategies to improve predictive capabilities for reproductive toxicology are suggested.
The Integrated Use of Models for the Properties and Effects of Chemicals by means of a Structured Workflow
Authors: Bassan Arianna , Worth Andrew P. 
Published: January 2008

AbstractThis paper reviews the applicability of different types of non‐testing methods and in silico tools in the framework of a structured workflow that aids their exploitation for the prediction of properties that contribute to hazard and risk assessments of chemicals. These properties include basic physicochemical properties, metabolic and environmental fate, and ecological and health effects of chemicals. The workflow for the use of methods comprises a structured sequence of operations that integrates the functionalities of a wide array of in silico tools. The workflow could be used for in‐house decision making (e.g. screening the properties of potential drugs and commercial chemicals) as well generating data required in regulatory submissions. The general workflow presented here is intended to broadly applicable to all endpoints and different regulatory frameworks, including the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation in the European Union (EU). The general framework can be adapted to meet the needs of specific chemicals, endpoints and regulatory purposes. This review is one of a series of minireviews in this journal.
Low‐lying singlet excited states of isocyanogen
Authors: Ringer Ashley L. , Sherrill C. David , King Rollin A. , Crawford T. Daniel 
Published: January 2008

AbstractRecent photofragment fluorescence excitation (PHOFEX) spectroscopy experiments have observed the Ã1A″ singlet excited state of isocyanogen (CNCN) for the first time. The observed spectrum is not completely assigned and significant questions remain about the excited states of this system. To provide insight into the energetically accessible excited states of CNCN, optimized geometries, harmonic vibrational frequencies, and excitation energies for the first three singlet excited states are determined using equation‐of‐motion coupled‐cluster theory with singles and doubles (EOM‐CCSD) and correlation‐consistent basis sets. Additionally, excited state coupled‐cluster methods which approximate the contributions from triples (CC3) are utilized to estimate the effect of higher‐order correlation on the energy of each excited state. For the Ã1A″ state, our best estimate for T0 is about 42,200 cm−1, in agreement with the experimentally estimated upper limit for the zero‐point level of 42,523 cm−1. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Potential energy surface and highly excited vibrational lines of NO2 via algebraic approach
Authors: Zheng Yujun , Ding Shiliang 
Published: January 2008

AbstractThe algebraic Hamiltonian of NO2 is optimized using U(4) algebra via fitting to 102 observed vibrational lines. The RMS error of the fitting is 2.39 cm−1. We calculated highly excited vibrational energy levels using this optimized Hamiltonian, and then obtained the potential energy surface for the electronic ground state by using the classical limit of the U(4) algebraic Hamiltonian. We also calculated the dissociation energies, the force constants etc. Our results are in good agreement with the other theoretical results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Computational Models of a Nano Probe Tip for Static Behaviors
Authors: Feng Shaw C. , Vorburger Theodore V. , Joung Che bong , Dixson Ronald G. , Fu Joseph , Ma Li 
Published: January 2008

AbstractIt is difficult to predict the measurement bias arising from the compliance of the atomic force microscope (AFM) probe. The issue becomes particularly important in this situation where nanometer uncertainties are sought for measurements with dimensional probes composed of flexible carbon nanotubes mounted on AFM cantilevers. We have developed a finite element model for simulating the mechanical behavior of AFM cantilevers with carbon nanotubes attached. Spring constants of both the nanotube and cantilever in two directions are calculated using the finite element method with known Young's moduli of both silicon and multiwall nanotube as input data. Compliance of the nanotube‐attached AFM probe tip may be calculated from the set of spring constants. This paper presents static models that together provide a basis to estimate uncertainties in linewidth measurement using nanotubes. In particular, the interaction between a multiwall nanotube tip and a silicon sample is modeled using the Lennard‐Jones theory. Snap‐in and snap‐out of the probe tip in a scanning mode are calculated by integrating the compliance of the probe and the sample‐tip interacting force model. Cantilever and probe tip deflections and points of contact are derived for both horizontal scanning of a plateau and vertically scanning of a wall. The finite element method and the Lennard‐Jones model provide a means to analyze the interaction of the probe and sample and measurement uncertainty, including actual deflection and the gap between the probe tip and the measured sample surface. SCANNING 30: 47–55, 2008. © 2008 Wiley Periodicals, Inc.
Cytotoxicity of Aggregated Fullerene C60 Particles on CHO and MDCK Cells
Authors: Han Binbing , Karim M. Nazmul 
Published: January 2008

AbstractThe cytotoxicity of fullerene C60 particles on two mammalian cell lines, i.e. the Chinese hamster ovary (CHO) cells and the Madin‐Darby canine kidney (MDCK) cells, has been investigated. Although innate fullerene particles have a very low solubility in deionized (DI) water, these particles can be dissolved in the tetrahydrofuran (THF) solvent at a great value. Further, the dissolved fullerene particles in the THF solvent could be extracted into a DI water solution at a significantly increased solubility. The formation of fullerene particle aggregates is believed to be the cause of the increased solubility. Results presented here show that once the concentration of the fullerene aggregates reaches a certain level, the cells start to die. The lethal dosage LD50, which is defined as the lowest fullerene concentration that results in a 50% cell death within 24 h, has been determined. Furthermore, the percentage of cell mortality increased with increasing fullerene concentration and incubation time yielding a negative effect on cell viability. These results, illustrated by atomic force microscopy (AFM), dynamic light scattering (DLS) and other microscopic techniques, will help to better understand the side effects of fullerene particles in mammalian cells. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
Achieving Precision and Reproducibility for Writing Patterns of n‐alkanethiol Self‐assembled Monolayers with Automated Nanografting
Authors: Ngunjiri Johnpeter N. , Kelley Algernon T. , Lejeune Zorabel M. , Li Jie‐Ren , Lewandowski Brian R. , Serem Wilson K. , Daniels Stephanie L. , Lusker Kathie L. , Garno Jayne C. 
Published: January 2008

AbstractNanografting is a high‐precision approach for scanning probe lithography, which provides unique advantages and capabilities for rapidly writing arrays of nanopatterns of thiol self‐assembled monolayers (SAMs). Nanografting is accomplished by force‐ induced displacement of molecules of a matrix SAM, followed immediately by the self‐assembly of n‐alkanethiol ink molecules from solution. The feedback loop used to control the atomic force microscope tip position and displacement enables exquisite control of forces applied to the surface, ranging from pico to nanonewtons. To achieve high‐resolution writing at the nanoscale, the writing speed, direction, and applied force need to be optimized. There are strategies for programing the tip translation, which will improve the uniformity, alignment, and geometries of nanopatterns written using open‐loop feedback control. This article addresses the mechanics of automated nanografting and demonstrates results for various writing strategies when nanografting patterns of n‐alkanethiol SAMs. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
Political, religious and occupational identities in context: Placing identity status paradigm in context
Authors: Solomontos‐Kountouri Olga , Hurry Jane 
Published: January 2008

ABSTRACTThis study critically contrasts global identity with domain‐specific identities (political, religious and occupational) and considers context and gender as integral parts of identity. In a cross‐sectional survey, 1038 Greek Cypriot adolescents (449 boys and 589 girls, mean age 16.8) from the three different types of secondary schools (state, state technical and private) and from different SES completed part of the Extended Objective Measure of Ego Identity Status‐2 (EOMEIS‐2). The macro‐context of Greek Cypriot society is used to understand the role of context in adolescents’ identities. Results showed that Greek Cypriot young people were not in the same statuses across their global, political, religious and occupational identities. This heterogeneity in the status of global identity and of each identity domain is partially explained by differences in gender, type of school and SES (socio‐economic status). The fact that identity status is found to be reactive to context suggests that developmental stage models of identity status should place greater emphasis on context.
The Co-ordinating State and the Economy: The Nizamat in Eighteenth-Century Bengal
Authors: MUKHERJEE TILOTTAMA 
Published: January 2008

AbstractThe economy of eighteenth-century Bengal was closely tied to the political, with the indigenous state, theNizamat, maintaining a stake in the success of commercial circuits. TheNizamatplayed a positive role in keeping the structure operative through its patronage and regulating activities. Besides its direct involvement in trade, the article examines the indirect facilitating and co-ordinating role it played, the elaboration of a distinct court culture and the policies it pursued which had a bearing on the health of the economy. The conditions necessary for the functioning of marketing networks—protection of property and enforcement of contract—were maintained. It was a mutually beneficial system with the state with its seat in Murshidabad, the landed élite of the region, and the commercial sector symbiotically tied together.
Social Phobia in an Outpatient Alcohol and Drug Treatment Sample
Authors: Adamson Simon J. , Sellman J. Douglas , Robertson Paul J. 
Published: January 2008

Objective: To examine characteristics of patients with social phobia (SP) in alcohol and drug treatment settings and to identify features distinguishing this group from patients with and without other psychiatric conditions. Method: A random sample of 105 patients completing an initial assessment at two outpatient alcohol and drug treatment services were assessed and agreed to a 9 month follow-up interview, completed by n=102 (97%). At baseline the Composite International Diagnostic Interview (CIDI) was administered. Current diagnoses at baseline were used to separate the sample into those with SP (n=33), other current psychiatric disorders (OPD, n=40), and those with no current psychiatric diagnosis other than a substance use disorder (NPD, n=29). The novel methodology used in this study compared the SP group first to the NPD group to see if SP was associated with a different presentation, and then compared the SP group to the OPD group to see if any identified differences were associated with SP per se or psychopathology generally. The three groups were compared on demographic, current clinical, and past treatment utilization variables at baseline, while follow-up data were used to compare the groups on treatment outcome and treatment utilization. Results: The SP group did not differ from either group in a systematic way. What differences did emerge tended to show a difference between OPD and NPD, with SP intermediate between the two, or that SP and OPD together were different from NPD. Conclusions: Despite the relatively small sample size, these findings suggest that in substance use disorder treatment settings, patients with coexisting SP do not represent a distinctly high-needs or at-risk group in the broader context of patient populations, for which coexisting psychiatric diagnoses are the norm rather than the exception.