bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new route of manipulation of poly(L‐lactic acid) crystallization by self‐assembly of p‐tert‐butylcalix[8]arene and toluene
Authors: Wen Liang , Xin Zhong , Hu Dongkang 
Published: April 2010

AbstractA novel nucleating agent (TBC8‐t), self‐assembled with p‐tert‐butylcalix[8]arene (TBC8) and toluene, was used to manipulate the crystallization behavior of poly(L‐lactic acid) (PLLA). Toluene molecules were used to adjust the crystallization structure of TBC8. Differential scanning calorimetry results show that the crystallization peak temperature (Tc) and crystallization rate (ΔHc/time) of PLLA nucleated with TBC8‐t are 132.3 °C and 0.24 J/gs, respectively, which are much higher than that with conventional nucleating agent‐talc (Tc = 119.3 °C, ΔHc/time = 0.13 J/gs). The results of polarized optical microscopy demonstrate that TBC8‐t could greatly enhance the crystallization rate of PLLA by increasing the nucleation rate rather than crystal growth rate. Along with an improvement of the crystallization rate, the crystalline morphology of PLLA is also affected by TBC8‐t. The addition of TBC8‐t transforms most of the original spherulite crystals into sheaf‐like crystals. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1235–1243, 2010
Another view on the analysis of cardiovascular morbidity/mortality trials
Authors: Rosenkranz Gerd K. 
Published: April 2010

AbstractIn many morbidity/mortality studies, composite endpoints are considered. Although the primary interest is to demonstrate that an invention delays death, the expected death rate is often that low that studies focussing on survival exclusively are not feasible. Components of the composite endpoint are chosen such that their occurrence is predictive for time to death. Therefore, if the time to non‐fatal events is censored by death, censoring is no longer independent. As a consequence, the analysis of the components of a composite endpoint cannot be reasonably performed using classical methods for the analysis of survival times like Kaplan–Meier estimates or log‐rank tests. In this paper we visualize the impact of disregarding dependent censoring during the analysis and discuss practicable alternatives for the analysis of morbidity/mortality studies. In the context of simulations we provide evidence that copula‐based methods have the potential to deliver practically unbiased estimates of hazards of components of a composite endpoint. At the same time, they require minimal assumptions, which is important since not all assumptions are generally verifiable because of censoring. Therefore, there are alternative ways to analyze morbidity/mortality studies more appropriately by accounting for the dependencies among the components of composite endpoints. Despite the limitations mentioned, these alternatives can at minimum serve as sensitivity analyses to check the robustness of the currently used methods. Copyright © 2010 John Wiley & Sons, Ltd.
Small‐load nanoindentation experiments on metals
Authors: Campbellová Anna , Klapetek Petr , Buršíková Vilma , Valtr Miroslav , Buršík Jiří 
Published: April 2010

AbstractThe loading curve dependency and presence of ‘pop‐in’ effects were studied for different materials and indentation methods specifically on metals with face‐centered cubic (Ni) and tetragonal (Sn) crystalline structures. The nanoindentation experiments were performed on a CSM UNHT (ultra nano hardness tester) instrument using a diamond Berkovich tip and on an atomic force microscope using a steel indentation cantilever. The dependence of the pop‐in creation on the grain orientation (determined using electron backscatter diffraction (EBSD)) was compared with those in the literature and molecular dynamics simulations, using a combination of the embedded atom method and density functional theory (DFT). Due to its computational demands, DFT was used only for validation of the performance of the classical molecular dynamics code. Copyright © 2010 John Wiley & Sons, Ltd.
Near‐field optical microscopy simulations using graphics processing units
Authors: Klapetek Petr , Valtr Miroslav 
Published: April 2010

AbstractScanning near‐field optical microscopy (NSOM) is a perspective method for local analysis of optical parameters of nanostructures used in electro‐optics, photonics and many other field of research. Due to complicated nature of topography‐related effects in the optical signal, which can influence or completely alter the NSOM data, the practical use of this method for quantitative analysis is still limited. One of the approaches to determine the effects of topography on optical data is to simulate NSOM images using an electromagnetic field modeling method, e.g. finite difference in time domain method. However, this approach is extremely slow, as full electromagnetic field propagation calculation must be run for each pixel of the resulting simulated image. In this paper, we present a fast method for computing simulated NSOM images based on the use of a graphics processing unit (GPU or computer graphics card) in order to speed up the computations. We will show that the large speedup using this approach (more than 40 times) allows us to simulate images in a time comparable to their real measurement, which increases the possibilities of quantitative analysis using NSOM. Data simulated by a GPU will be compared with those of real measurements as well. Copyright © 2010 John Wiley & Sons, Ltd.
An XPS study of the interatomic charge distribution in stainless steels
Authors: Diplas S. , Moslemzadeh N. , Watts J. F. , Beamson G. , Tsakiropoulos P. 
Published: April 2010

AbstractThe secondary spectral feature of the Al Kα‐excited Ni 2p spectrum, positioned at a kinetic energy of approximately 6 eV lower than the main Ni 2p peak, is known as either the 2p satellite (in the case of inorganic materials) or a plasmon loss peak (in the case of metals). This feature was used to probe changes in the local electronic structure of Ni in stainless steels. The results were compared with a previous study on Auger parameter and core–core–valence (CCV) Auger lines acquired using Cu Kα radiation. The position of the secondary peak shifts to higher binding energy as the number of Fe atoms around Ni increases and this is consistent with the idea of charge transfer from Fe to Ni 3d irrespective of whether the peak is treated as a plasmon or satellite. Previous studies on Ni alloys showed that as the concentration of the more electropositive partners in the Ni alloy (such as Fe in a NiFe alloy) increased compared to Ni, the intensity of the Ni energy loss decreased. However, contrary to previous studies, in steels that we studied, the intensity of the secondary peak increases as the concentration of Fe (or even Cr) increases. Copyright © 2010 John Wiley & Sons, Ltd.
Nanopowders with superparamagnetic Fe3C particles and their annealing behaviour
Authors: David B. , Schneeweiss O. , Pizúrová N. , Dumitrache F. , Fleaca C. , Alexandrescu R. 
Published: April 2010

AbstractTwo samples of nanopowders containing superparamagnetic Fe3C and Fe3O4/γ–Fe2O3 particles and carbon black were synthesized by the method of laser‐induced homogeneous pyrolysis of gaseous precursors. Both were characterized by XRD, HR‐TEM, Mössbauer spectrometry and standard magnetic measurements. The mean crystallite size of Fe3C was 3 nm for the first sample and 10 nm for the second sample. Fe3C phase in both samples exhibited reduced Curie temperature and smeared ferromagnetic–paramagnetic transition. After annealing of the samples at 800 °C for 30 min the Curie temperature of the recrystallized Fe3C phase in both samples was ∼214 °C (standard bulk value). Copyright © 2010 John Wiley & Sons, Ltd.
Leptin Functions Peripherally to Regulate Differentiation of Mesenchymal Progenitor Cells
Authors: Scheller Erica L. , Song Junhui , Dishowitz Michael I. , Soki Fabiana Naomi , Hankenson Kurt D. , Krebsbach Paul H. 
Published: April 2010

Abstract
Leptin functions through a well-documented central neuroendocrine pathway to regulate bone mass. However, the ability of leptin to modulate bone mass through a peripheral mechanism has been debated due to conflicting in vitro results and lack of sufficient in vivo models. We utilized mice with LoxP sites introduced into the long-form leptin receptor (ObRb) gene to determine how leptin regulates mesenchymal progenitor cell (MPC) differentiation and osteoblast function in vitro and in vivo. Rapid phosphorylation of Stat3 after leptin treatment of bone marrow stromal cells (BMSCs) from mice with conditional deletion of ObRb in macrophages (LysMCre+F/F) confirmed expression of functional leptin receptors by BMSCs. Adenovirus-Cre mediated disruption of ObRb in primary stromal cells decreased mineralization and increased adipogenesis. In contrast, BMSCs harvested from leptin-signaling deficient Ob/Ob or Db/Db mice showed increased mineralization. To determine the physiologic relevance of these differences, mice with cell-specific deletion of ObRb in mesenchymal precursors (3.6Cre+F/F) or osteoblasts (2.3Cre+F/F) were generated. Although the 2.3Cre+F/F mice were grossly normal, the 3.6Cre+F/F mice displayed mild obesity that was not attributed to food intake. Femurs of 3.6Cre+F/F animals showed a 58%–61.9% increase in trabecular bone volume and a 65.5%–74% increase in bone mineral density. Cortical volume and mineral content were also increased 18%–22%. Primary 3.6Cre+F/F BMSCs recapitulated the high mineralization phenotype of Ob/Ob and Db/Db BMSCs. We conclude that leptin may have multiple peripheral roles depending on the differentiation state of MPC. Leptin (a) helps maintain MPCs in an undifferentiated state and (b) promotes mineralization of more differentiated osteoblasts.
RFID reader collision problem: performance analysis and medium access
Authors: Yoon Wonyong , Vaidya Nitin H. 
Published: April 2010

AbstractThe RFID reader collision problem, in which an RFID reader's interrogation is interfered by other concurrent readers' transmission, is considered an important issue to reliable operation and thus to the wide‐spread deployment of RFID networks. In this paper, we present modeling and analysis of the RFID reader collision problem. We observe asymmetry between an RFID reader's and a tag's communication capabilities and develop an RFID radio model based on the asymmetry. By the model, we characterize the spatial reuse of RFID reader networks, and deriveconcurrent interrogation distancebeyond which readers can transmit simultaneously without causing collision and the carrier sense threshold corresponding to the distance. We also examine the dual‐channel mode where available bandwidth is divided into two channels by which reader‐to‐tag communication and tag‐to‐reader communication are separated. We analyze and evaluate the performance of the dual‐channel mode in terms of spatial reuse and interrogation completion time. Copyright © 2010 John Wiley & Sons, Ltd.
The development of emotion
Authors: Marshall Peter J. 
Published: April 2010

AbstractGiven that they are responsible for much of the meaning that we attribute to our existence, emotions could be said to have a central role in the psychological life of humans. But given this fundamental level of significance, the construct of emotion remains poorly understood, with the field of emotion research being full of conflicting definitions and opposing theoretical perspectives. In this review, one particular aspect of research into emotion is considered: the development of emotion in infancy and early childhood. The development of the emotional life of the child has been the focus of a vast amount of research and theorizing, so in a brief review it is only possible to scratch the surface of this topic. Rather than any attempt at a comprehensive account, three perennial questions in theorizing and research on early emotional development will be considered. First, what develops in emotional development? Second, what is the relation of cognitive development to emotional development? Third, how has the study of early individual differences in emotion expression typically been approached? In relation to the first question, four theoretical approaches to emotional development are described. For the second question, the focus is on the relation of self‐awareness to the development of emotion. Finally, for the third question, the use of temperament theory as a framework for understanding individual differences in emotion expression is examined. Copyright © 2010 John Wiley & Sons, Ltd.This article is categorized under:Psychology > Development and AgingPsychology > Emotion and Motivation
Aging and cognition
Authors: Mather Mara 
Published: April 2010

AbstractAs we grow older, we gain knowledge and experience greater emotional balance, but we also experience memory loss and difficulties in learning new associations. Which cognitive abilities decline, remain stable or improve with age depends on the health of the brain and body as well as on what skills are practiced or challenged in everyday life. Recent research provides a growing understanding of the relationship between physical and cognitive changes across the life span and reveals ways to increase mental sharpness and avoid cognitive decline. Copyright © 2010 John Wiley & Sons, Ltd.This article is categorized under:

Psychology > Development and Aging
Electrophysiological models of neural processing
Authors: Nelson Mark E. 
Published: April 2010

AbstractThe brain is an amazing information processing system that allows organisms to adaptively monitor and control complex dynamic interactions with their environment across multiple spatial and temporal scales. Mathematical modeling and computer simulation techniques have become essential tools in understanding diverse aspects of neural processing ranging from sub‐millisecond temporal coding in the sound localization circuity of barn owls to long‐term memory storage and retrieval in humans that can span decades. The processing capabilities of individual neurons lie at the core of these models, with the emphasis shifting upward and downward across different levels of biological organization depending on the nature of the questions being addressed. This review provides an introduction to the techniques for constructing biophysically based models of individual neurons and local networks. Topics include Hodgkin‐Huxley‐type models of macroscopic membrane currents, Markov models of individual ion‐channel currents, compartmental models of neuronal morphology, and network models involving synaptic interactions among multiple neurons. WIREs Syst Biol Med 2011 3 74–92 DOI: 10.1002/wsbm.95This article is categorized under:

Models of Systems Properties and Processes > Mechanistic Models
MOFs by Transformation of 1D‐Coordination Polymers II: The Homoleptic Divalent Rare Earth 3D Benzotriazolate $\rm ^3_\infty[Eu(Btz)_2]$ Initiating from $\rm ^1_\infty[Eu(Btz)_2(BtzH)_2]$
Authors: Rybak Jens‐Christoph , Schellenberg Inga , Pöttgen Rainer , Müller‐Buschbaum Klaus 
Published: April 2010

AbstractThe solvent free reaction route produces coordination polymers that have a dimensionality of the linkage, which is increasing with the thermal energy. The synthesis of the 3D metal organic framework (MOF) structure $\rm ^3_\infty[Eu(Btz)_2]$ marks the final thermal reaction step within the system europium/1H‐1,2,3‐benzotriazole. It can be obtained by a reaction of the metal with a melt of benzotriazole above 230 °C or from thermal treatment of the 1D coordination polymer$\rm ^1_\infty[Eu(Btz)_2(BtzH)_2]$ (Btz– = 1,2,3‐benzotriazolate anion, C6H4N3–; BtzH = 1H‐1,2,3‐benzotriazole, C6H5N3), which is formed first at about 100 °C from the same reagents. In addition to the trivalent rare earth ions it can thus be shown that also divalent EuII together with benzotriazole exhibits transformation of a 1D coordination polymer into a 3D MOF. The homoleptic framework $\rm ^3_\infty[Eu(Btz)_2]$ exhibits a high thermal stability (525 °C) for an exothermically decomposing coordination compound. As $\rm ^3_\infty[Eu(Btz)_2]$ is always obtained as a microcrystalline product, structure solution and refinement were achieved by X‐ray powder techniques. For further characterization 151Eu‐Mössbauer, IR, and Raman spectroscopy as well as micro and thermal analysis were carried out.
Mixed Valence Tungsten (IV,V) Compounds with Layered Structures (Part III) [2]: Synthesis and Crystal Structure of Ag1–x[W2O2Cl6] and Investigations on the Ag+ Ion Mobility
Authors: Beck Johannes , Hoffbauer Wilfried , Kusterer Christian , Schieweling Marcel 
Published: April 2010

AbstractThe reaction of metallic silver with tungsten tetrachlorideoxide WOCl4 or the reaction of AgCl with WOCl3, both at 690 K, lead to Ag1–x[W2O2Cl6] as black lustrous crystal needles. The compound shows a substantial phase field width in the silver content depending on reaction temperature and reaction time and crystals with x = 0, 0.38 and 0.82 were isolated. The crystal structure determinations (monoclinic, C2/m) show the structure to be isotypic to those of Tl[W2O2Cl6] and K0.84[W2O2Cl6] with the presence of 1D polymeric [W2O2Cl6]n strands and Ag+ ions with a variety in the occupation of the respective crystallographic site. Ag1–x[W2O2Cl6] represents a mixed valence compound with a variable ratio of W(IV) and W(V) in the W2 dumbbells with a short W–W separation of 2.85 Å. In Fourier maps the electron density of the Ag ion appears smeared over a large area. By structure determinations of stoichiometric Ag1.0[W2O2Cl6] at temperatures of 123, 193, and 293 K a double minimum potential was found with the silver ion dynamically disordered over two flat basins with a thermal activation barrier of 13 meV. No long range ion mobility is present since the Ag+ ions are trapped within a coordinating cage consisting of ten chlorine atoms of the surrounding [W2O2Cl6] strands forming a distorted bicapped cube. By MAS‐NMR spectroscopic measurements on the 109Ag nuclei at different temperatures, the spin lattice relaxation times were determined giving a thermally activated barrier of 15 meV. The electronic conductivity of pressed powder samples of Ag[W2O2Cl6] by a four‐probe measurement applying direct current is 1 Ω–1·cm–1 at room temperature and 10–3 Ω–1·cm–1 at 25 K. For the conduction mechanism at low temperatures a variable range hopping mechanism is suggested, whereas at higher temperatures a standard semi‐conductivity with a bandgap of 60 meV is present.
Prevalence, Risk Factors, and Management of Seroma Formation After Breast Approach Endoscopic Thyroidectomy
Authors: Shan Cheng‐Xiang , Zhang Wei , Jiang Dao‐Zhen , Zheng Xiang‐Min , Liu Sheng , Qiu Ming 
Published: April 2010

AbstractBackgroundBreast approach endoscopic thyroidectomy (BAET) allows surgeons to remove a thyroid tumor from a remote site while providing a scarless cosmetic appearance in the neck. However, seroma formation after subcutaneous dissection could lead to flap detachment, incision dehiscence, and wound infection. Chronic formation of seromas could substantially compromise the esthetic outcome of BAET. We evaluated the prevalence, risk factors, and treatments of seroma after BAET.MethodsA total of 344 patients who underwent BAET between 2001 and 2008 at our institution were recruited; data were collected prospectively. The characteristics and outcomes of patients who developed seromas were compared with those of patients who did not. Regression analysis was used to identify the independent risk factors for seroma formation. The frequency and volume of aspirations were noted until the seroma went into remission.ResultsThe overall postoperative prevalence of seroma formation was 2.9%. There was a significant difference in seroma formation based on age, hypertension, body mass index (BMI), and area of subcutaneous dissection space (ASDS). Percutaneous aspiration alone or combined with external compression was extremely effective. The frequency and total volume of aspirations were 1–7 and 6–120 ml, respectively. As a result of prolonged seroma formation, one patient developed an expanding pseudo‐bursa that created a tumor‐like effect in the anterior chest wall.ConclusionsSeroma formation was an uncommon minor complication after BAET. Four independent etiologic factors could predispose patients to postoperative seroma formation. Percutaneous aspiration appeared to be very effective. Prolonged seroma formation followed by development of a pseudo‐bursa could be very problematic and could substantially impair the esthetic effect of BAET.
Estimating demographic parameters for loggerhead sea turtles using mark–recapture data and a multistate model
Authors: Monk Melissa Hedges , Berkson Jim , Rivalan Philippe 
Published: April 2010

AbstractThe survival for adult loggerhead sea turtles from a saturation tagging study on Bald Head Island, NC, USA, was estimated using a multistate model with unobservable states to relax assumptions that are violated when survival is estimated from multistate models and produce more accurate estimates of survival, recapture, and breeding transition probabilities. The influence of time, trap dependence, and low site fidelity to the study nesting beach on survival and recapture were examined. The best model given the data included an imprecise site‐fidelity effect on survival, constrained the reproductive cycle to 4 years, and contained a time effect on recapture rates. The estimate of annual survival for adult females was of 0.85, producing the highest estimate in the literature for loggerhead sea turtles. Multistate models should be applied to other nesting beach data for sea turtles to improve survival estimates and in turn the ability to model and manage populations.
A resource dependence theory perspective of ISO 9000 in managing organizational environment
Authors: Singh Prakash J. , Power Damien , Chuong Sum Chee 
Published: April 2010

AbstractMore than 900,000 organizations worldwide have registered to the ISO 9000 quality management standard. Despite its growing popularity, few studies have offered a coherent theoretical basis for the standard's appeal. A theory‐based explanation enhances understanding and appreciation for the standard, and provides clarity on how the standard benefits organizations. In this paper, we invoke the resource dependence theory (RDT) to purport that the standard is used by organizations as a tool to manage their organizational environment. It does this by specifying procedures that organizations need to manage their organization–environment boundary spanning processes. Using the RDT perspective, a model with three key constructs embodying ISO 9000 was developed: internal processes, relationships with customers and relationships with suppliers. The latter two were treated as being part of the task environment. We predicted that the external aspects of the standard affect operating performance (a measure of effectiveness), both directly and through internal processes. Empirical data from 416 ISO 9000 registered Australian manufacturing plants validated the RDT perspective, and suggest that the three constructs, individually and in isolation, are not as effective as when they are considered together. By invoking RDT, a new theoretical viewpoint to ISO 9000 has been developed that adds to other theoretical perspectives, and goes some way to explaining the growing popularity of this standard with organizations.