bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrafast optical Kerr effect of excitons weakly confined in GaAs thin films
Authors: Kanno Atsushi , Katouf Redouane , Kojima Osamu , Ishi‐Hayase Junko , Tsuchiya Masahiro , Isu Toshiro 
Published: October 2007

AbstractWe investigate ultrafast response of optical Kerr effect (OKE) induced by excitons weakly confined in GaAs thin films. The observed decay time of optical response agrees approximately with incident pulse duration. At 100‐fs pulse irradiation the response time is estimated to be 170 fs, though the exciton lifetime is about 10 ns. It is considered that the ultrafast response of OKE is caused by not population relaxation but orientation relaxation of excitons. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Direct observation of Landau damping in a solid state plasma
Authors: Hasselbeck M. P. , Seletskiy D. , Dawson L. R. , Sheik‐Bahae M. 
Published: October 2007

AbstractWe use ultrafast THz spectroscopy to study Landau damping in a coherent plasma system. A series of InSb‐based bulk heterostructures provide increasing spatial confinement that restricts the scattering wave vector in the electron‐electron interaction. This results in a dramatic reduction of the plasma contribution to the radiation signal. The experimental results are explained by model calculations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generation of TeraHertz radiation assisted by optical phonons in nitride‐based quantum wells and heterolayers
Authors: Shiktorov P. , Starikov E. , Gružinskis V. , Varani L. , Palermo C. , Torres J. , Chusseau L. 
Published: October 2007

AbstractTo analyze the main features of THz radiation generation caused by optical‐phonon transit‐time resonance in the case of bidimensional transport, a simplified analytical model is developed in terms of generalized parameters of bulk materials and 2D structures. In the framework of such a model and direct Monte Carlo simulations, it is shown that for a given material: (i) the generation conditions are the same in quantum wells and heterolayers, and they can be characterized by the same parameter related to the effective width of the 2D‐channel and with the optical phonon momentum, (ii) a considerable increase up to 5 times of the high‐frequency cut‐off for THz radiation generation is predicted in going from 3D to 2D transport. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Few‐particle electron dynamics in coupled quantum dots with phonon interaction
Authors: Bertoni Andrea , Climente Juan I. , Rontani Massimo , Goldoni Guido , Hohenester Ulrich 
Published: October 2007

AbstractThe time evolution of a correlated multi‐electron state in a semiconductor coupled quantum dot, interacting with the acoustic phonon bath, is calculated within the master equation formalism, including electron‐electron interaction exactly through the configuration‐interaction approach. The system is evolved after an initialization phase, with the system under strong bias, leading to the charge density mainly localized in one of the dots. When the system is evolved (in unbiased condition), damped multi‐frequency charge oscillations are found, which strongly depend on the 3D system geometry and initialization. We describe the approach used to obtain the multi‐electron states and to include the phonon‐induced transitions between them in the time evolution. Furthermore, the effect of a magnetic field applied in the axial direction of the vertical double‐dot cylindrical structure is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
3D Monte Carlo simulation including full Coulomb interaction under high electron concentration regimes
Authors: Uechi Tadayoshi , Fukui Takayuki , Sano Nobuyuki 
Published: October 2007

AbstractWe construct 3D Monte Carlo (MC) simulations including the full Coulomb interaction as accurately as possible. In order to achieve this goal, the usual strategy for the MC approach is employed; the Coulomb potential is split into the long‐range and the short‐range parts. The long‐range part of the Coulomb potential is taken into account by solving the Poisson equation, in which the simulation parameters such as mesh size, charged‐particle size, time step etc are carefully optimized by performing the particle simulations with turning off artificially all short‐ranged scatterings. The short‐range part of the Coulomb potential is incorporated into the MC simulations as scattering processes by developing a new scattering model, in which the impurities are localized in real space. It is shown that the present 3D MC simulations successfully explain the entire regime of the electron mobility as a function of impurity concentrations. In addition, it is found for the first time that the plasma frequency is modulated due to localization of the background impurities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization strategy based on genetic algorithms and neural networks applied to a polymerization process
Authors: Curteanu Silvia , Leon Florin 
Published: October 2007

AbstractThe article presents a simple and general methodology, especially destined to the optimization of complex, strongly nonlinear systems, for which no extensive knowledge or precise models are available. The optimization problem is solved by means of a simple genetic algorithm, and the results are interpreted both from the mathematical point of view (the minimization of the objective function) and technological (the estimation of the achievement of individual objectives in multiobjective optimization). The use of a scalar objective function is supported by the fact that the genetic algorithm also computes the weights attached to the individual objectives along with the optimal values of the decision variables. The optimization strategy is accomplished in three stages: (1) the design and training of the neural model by a new method based on a genetic algorithm where information about the network is coded into the chromosomes; (2) the actual optimization based on genetic algorithms, which implies testing different values for parameters and different variants of the algorithm, computing the weights of the individual objectives and determining the optimal values for the decision variables; (3) the user's decision, who chooses a solution based on technological criteria. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Partitioning of atomization energy
Authors: Vyboishchikov Sergei F. 
Published: October 2007

AbstractThe present work provides a technique for partitioning the atomization energy of a molecule into diatomic contributions. The method is largely based on the redistribution of the kinetic energy term in Mayer's energy partitioning and uses free‐atom energies as a reference. The comparison of Mayer's original method, the alternative Ichikawa–Yoshida approach, and the new atomization energy partitioning (AEP) shows that the new approach has advantages in describing trends in diatomic energies in molecules with triple bonds, as well as for hydrogen bonds. The proposed AEP is a viable alternative to Mayer's energy partitioning method. © 2007 Wiley Periodicals, Inc. Int. J. Quantum Chem, 2008
The non‐destructive identification of solid over‐the‐counter medications using single particle aerosol mass spectrometry
Authors: Martin Audrey N. , Farquar George R. , Jones A. Daniel , Frank Matthias 
Published: October 2007

AbstractSingle over‐the‐counter medication tablets were analyzed in real time using Single Particle Aerosol Mass Spectrometry (SPAMS). Dual‐polarity time‐of‐flight mass spectra were obtained for micrometer‐sized single particles dislodged from a single tablet without destroying the shape or markings of each tablet. The solid tablet was placed in a modified‐top glass vial and shaken to dislodge and introduce micrometer‐sized particles into the SPAMS system. Unique spectra from these particles were obtained in less than 1 s for single tablets of aspirin, ibuprofen, pseudoephedrine, phenylephrine, loratadine, or diphenhydramine. The signals obtained allowed the non‐destructive identification of an individual tablet in seconds. SPAMS presents an ideal system for high‐throughput analysis of solid drugs. Copyright © 2007 John Wiley & Sons, Ltd.
Oligodeoxyribonucleotide Association with Single‐Walled Carbon Nanotubes Studied by SPM
Authors: Lahiji Roya R. , Dolash Bridget D. , Bergstrom Donald E. , Reifenberger Ronald 
Published: October 2007

AbstractStudies have been performed on both as‐received and chemically oxidized single‐walled carbon nanotubes (SWCNTs) grown by two different growth methods to better understand the preferential association of the oligodeoxyribonucleotide T30 (ODN) with SWCNTs. Samples of T30 ODN:SWCNT were examined under ambient conditions using non‐contact scanning probe microscope (SPM) techniques. The resulting images show different morphologies ranging from tangled networks of SWCNTs to individual, well‐dispersed isolated SWCNTs as the sonication time is increased. SPM images of well‐dispersed, as‐received SWCNTs reveal isolated features that are 1.4 to 2.8 nm higher than the bare SWCNT itself. X‐ray photoemission spectroscopy (XPS) confirmed these features to be T30 ODN in nature. Chemically oxidizing the SWCNTs before sonication is found to be an effective way to increase the number of T30 ODN features.
Preparation of a Panoscopic Mimic Diatom from a Silicon Compound
Authors: Fei Bin , Hu Zhigang , Lu Haifeng , Xin John H. 
Published: October 2007

AbstractInspired by biological design principles, a panoscopic mimic diatom was created by hierarchical self‐assembly of reactive amphiphiles in a multiphase medium comprising hexadecane, ethanol, water, and hydrochloric acid. Through simple stirring at room temperature, mesolamellar macroporous capsules covering oil droplets were obtained in large quantity, which was confirmed by NMR spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetry. At the mesoscale, amphiphilic C16Si(OH)3 assembled into bilayer lamellae through polycondensation, hydrophobic interaction, and H bonding. At the micrometer scale, the bilayer lamellae nucleated at the interface and grew into a polar phase, thus leading to delicate microcages or mimic diatoms. Moreover, the microcages tended to interconnect and fuse into a continuous coating at the centimeter scale, which provided hydrophobicity through the micropatterned surface. This paradigm for creating hierarchical materials with multiphases could lead to new “synthetic” material technologies and novel fascinating materials with anisotropic properties.
Enhancement of Polymer Luminescence by Excitation‐Energy Transfer from Multi‐Walled Carbon Nanotubes
Authors: Henley Simon J. , Hatton Ross A. , Chen Guan Y. , Gao Chao , Zeng Hailin , Kroto Harold W. , Silva S. Ravi P. 
Published: October 2007

AbstractCarbon nanotubes have been shown to efficiently quench luminescence from conjugated polymers when incorporated in a composite. However, shown here is an up to 100‐fold increase in the visible photoluminescence signal from fluorescent chromophores in nylon 10,10 by incorporating multi‐walled carbon nanotubes (MWCNTs). Using 325‐ and 488‐nm excitation the optical absorption by MWCNTs embedded within the polymer matrix is demonstrated, followed by efficient excitation‐energy transfer to emissive chromophores intrinsic to the polymer but only when the MWCNTs are acid functionalised. Furthermore, the MWCNTs are shown to significantly retard photobleaching of fluorescent centers in the nylon composites. These remarkable properties greatly advance the prospects of utilizing MWCNTs in organic solar cells and electroluminecent devices to improve performance.
Using the Ring‐Shaped Protein TRAP to Capture and Confine Gold Nanodots on a Surface.
Authors: Heddle Jonathan G. , Fujiwara Isamu , Yamadaki Hirokazu , Yoshii Shigeo , Nishio Kazuaki , Addy Christine , Yamashita Ichiro , Tame Jeremy R. H. 
Published: October 2007

AbstractThe cavity of the toroidal protein TRAP (trp RNA‐binding attenuation protein) is modified to capture gold nanodots in solution. By engineering a titanium‐binding peptide onto one surface of the ring it is also possible to bind it specifically and tightly to a TiO2 surface. TRAP bound in this way is then used to capture gold nanodots and attach them to prepared surfaces. Gold‐protein complexes are observed using atomic force microscopy and transmission electron microscopy. The modified TRAP is used to build gold nanodots into the SiO2 layer of a metal oxide semiconductor. This is the first use of a ring protein, rather than the more commonly used spherical protein cages, to constrain nanodots to a surface. This method is an important addition to the current range of bionanotechnology tools and may be the basis for future, multicomponent electronic devices.
Relationship between lung area at ultrasound examination and lung volume assessment with magnetic resonance imaging in isolated congenital diaphragmatic hernia
Authors: Jani J. , Cannie M. , Done E. , Van Mieghem T. , Van Schoubroeck D. , Gucciardo L. , Dymarkowski S. , Deprest J. A. 
Published: October 2007

AbstractObjectivesTo prospectively examine the relationship between contralateral lung area measured by two‐dimensional (2D) ultrasound examination and contralateral and total fetal lung volume (FLV) estimated by magnetic resonance imaging (MRI) in the assessment of fetuses with congenital diaphragmatic hernia (CDH).MethodsSixty‐six fetuses with isolated CDH were entered in this prospective study. Contralateral fetal lung area was measured by 2D ultrasonography using the longest axis method. Ipsilateral, contralateral and total FLV were measured using multiplanar axial T2‐weighted MRI. Regression analysis was used to determine the significance of associations between contralateral lung area and contralateral and total FLV, and the predicted total FLV was subsequently calculated using the regression equation. Univariate regression analysis was used to investigate the effect on the proportionate difference between the predicted and the observed total FLV of gestational age, proportionate volume of ipsilateral vs. total FLV, side of CDH, intrathoracic herniation of the liver and intratracheal presence of a balloon.ResultsThe 66 fetuses underwent a total of 191 paired 2D ultrasound and MRI examinations at a median gestational age of 30 (range, 18–38) weeks. It was possible to visualize and measure the contralateral lung area by 2D ultrasound, as well as both the ipsilateral and contralateral lung volumes by MRI, in all instances. There was a significant association between contralateral lung area and contralateral lung volume (r = 0.86; P < 0.001) and with total FLV (r = 0.84; P < 0.001). Univariate regression analysis showed that the proportionate difference between the predicted and the observed total FLV was significantly associated with the proportionate volume of ipsilateral vs. total FLV but not with gestational age, side of CDH, intrathoracic herniation of the liver or intratracheal presence of the balloon.ConclusionsIn CDH, contralateral lung area measurement by 2D ultrasound correlates well with the total FLV estimated by MRI, irrespective of gestational age, liver herniation or side of herniation. Inconsistencies between the two measurements are attributable to the contribution of the ipsilateral lung to the total lung volume. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Value of preoperative ultrasound examination in the selection of women with adnexal masses for laparoscopic surgery
Authors: Yazbek J. , Helmy S. , Ben‐Nagi J. , Holland T. , Sawyer E. , Jurkovic D. 
Published: October 2007

AbstractObjectivesTo assess the value of preoperative ultrasound examination in predicting the feasibility of intermediate‐level laparoscopic surgery for benign adnexal masses.MethodsSymptomatic women with a clinical or ultrasound diagnosis of adnexal mass were offered a detailed transvaginal ultrasound scan in order to assess the feasibility of laparoscopic cystectomy/oophorectomy. In all cases an attempt was made to establish a likely histological diagnosis using the pattern recognition method. The selection criteria for laparoscopic surgery were: no ultrasound features suggestive of ovarian cancer, predominantly cystic lesion with no solid foci > 5 cm in mean diameter, no evidence of severe pelvic endometriosis or severe pelvic adhesions and dermoid cyst < 10 cm in mean diameter. Laparoscopic surgery was classified as successful if the mass was removed completely without resorting to a laparotomy.ResultsOne hundred and forty‐three women were diagnosed with a total of 162 adnexal cysts. The final dataset consisted of 137 women (with 153 lesions), 113 (82.5%) of whom were selected for laparoscopy and 24 (17.5%) for laparotomy. On histological examination 152 (99.3%) cysts were benign and the remaining one (0.7%) was borderline. The operation was successfully completed laparoscopically in 107/113 (94.7%) cases. The preoperative ultrasound assessment predicted the successful outcome of laparoscopic surgery with a sensitivity of 98% (95% CI, 94–99%), specificity of 79% (95% CI, 60–90%), positive predictive value of 95% (95% CI, 89–98%), positive likelihood ratio of 4.58 (95% CI, 2.25–9.32) and negative likelihood ratio of 0.02 (95% CI, 0.01–0.09).ConclusionsA detailed preoperative transvaginal ultrasound examination is a helpful tool for assessing the feasibility of intermediate‐level laparoscopic surgery in women with benign adnexal lesions. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Determination of the elemental distribution in human joint bones by SR micro XRF
Authors: Zoeger N. , Streli C. , Wobrauschek P. , Jokubonis C. , Pepponi G. , Roschger P. , Hofstaetter J. , Berzlanovich A. , Wegrzynek D. , Chinea‐Cano E. , Markowicz A. , Simon R. , Falkenberg G. 
Published: October 2007

AbstractIn humans the toxic trace element lead (Pb) mainly accumulates in the skeletal tissue where it resides for a long period. Although Pb is known to play a role in bone and cartilage diseases, the distribution of Pb in these tissues is mostly unknown. Therefore synchrotron‐radiation‐induced micro x‐ray fluorescence analysis (SR µ‐XRF) in various geometries was used to determine the distributions of Pb, Ca, Zn and Sr at the cartilage‐bone interface in human femoral heads and patellae. SR µ‐XRF results were matched with backscattered electron (BE) images providing information on structural features of the tissue. Conventional SR µ‐XRF at HASYLAB beamline L showed that Pb mostly accumulates in a zone of some micrometers around the transition between non‐calcified and calcified cartilage. However, the relatively large sample thickness did not allow more precise conclusions. Exploiting the 3D capabilities of confocal SR µ‐XRF and SR microfluorescence tomography at ANKA Fluo‐Topo beamline and HASYLAB beamline L, the spatial resolution could be improved and a highly specific accumulation of Pb at the tidemark, the calcification front between non‐calcified and calcified cartilage, was detected. It was found that Pb and Zn accumulation coincide at the tidemark. Since the tidemark plays an important role in osteoarthritis, the results may strengthen other authors' conclusions that Pb is associated with this joint disease. Although offering less spatial resolution when compared to micro‐tomography, confocal SR µ‐XRF is best suited for such studies. It facilitates the comparison of element maps with other imaging techniques like BE imaging. Copyright © 2007 John Wiley & Sons, Ltd.
Coming Full Circle: A Reciprocal‐Engagement Model of Genetic Counseling Practice
Authors: Veach Patricia McCarthy , Bartels Dianne M. , LeRoy Bonnie S. 
Published: October 2007

AbstractAs genetic health care and genetic testing expand from primarily addressing conditions that are exclusively genetic in nature to common diseases with both genetic and environmental components, the scope of genetic counseling has grown. Identification and utilization of a normative model of practice defined by members of the profession is critical as genetic services become more commonplace in medical care. The purpose of this paper is to describe the results of a consensus conference convened to define a model of genetic counseling practice based on the guidance of educators and leaders in the profession. Twenty‐three program directors or their representatives from 20 genetic counseling graduate programs in North America listened to presentations and participated in group discussions aimed at determining the elements of a model of practice, including tenets, goals, strategies, and behaviors for addressing patients’ genetic concerns. Their discussion is summarized, training implications and research recommendations are presented, and a model of practice that extends their ideas is proposed.
Spatial variation of species diversity across scales in an old‐growth temperate forest of China
Authors: Wang Xugao , Hao Zhanqing , Ye Ji , Zhang Jian , Li Buhang , Yao Xiaolin 
Published: October 2007

AbstractSpecies richness and abundance are the two most important diversity variables. Species abundance is additive when aggregated across spatial scale, whereas species richness is non‐additive. This study analyzes the effect of spatial scale and site on species abundance and richness in a 25‐ha temperate forest plot in the Changbai Mountains, northeastern China. The result shows that species abundance and richness are not only dependent on spatial scales, but also dependent on site. Species abundance responds linearly to changes of spatial scale with no intersection in different sites of the study area. However, although species richness also increases with the increase of spatial scale, there are some intersections for the different sites, suggesting that a species‐rich site does not always have a high value if the spatial scale is changed. In all, with respect to additive variables, it is relatively easy to extrapolate them from one spatial scale to another spatial scale, as they and the spatial scale usually form a linear relationship. In contrast, non‐additive variables are difficult to extrapolate across spatial scales, because they often respond nonlinearly to spatial scale changes. In order to extrapolate these non‐additive variables across spatial scales, it is necessary to estimate the relationships between them and spatial scales. As a result, extrapolation of information among spatial scales may be possible, but very difficult, especially for non‐additive variables. Because the 25‐ha Changbai plot is very small compared to the extent of the world temperate forests, and the vegetation is a relatively uniform type, more such studies in other ecosystems are needed before theories and generalization about scaling effects can be formulated.