bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced Carbon Dots versus Oxidized Carbon Dots: Photo‐ and Electrochemiluminescence Investigations for Selected Applications
Authors: Xu Yang , Wu Ming , Feng Xi‐Zeng , Yin Xue‐Bo , He Xi‐Wen , Zhang Yu‐Kui 
Published: March 2013

AbstractThe study of the composition, morphology, and surface structure of carbon dots (Cdots) is critical to understanding their effect on the photo‐ and electrochemiluminescence (PL and ECL) of Cdots in selected applications. Herein, two kinds of Cdots were prepared with 3‐(3,4‐dihydroxyphenyl)‐L‐alanine (L‐DOPA) as precursor. The Cdots prepared by using a carbonization‐extraction strategy have a low oxidation level and are denoted as reduced Cdots (r‐Cdots). The Cdots obtained with a carbonization‐oxidation process are highly oxidized and are denoted as oxidized Cdots (o‐Cdots). The o‐Cdots have a carbon core and oxygen‐containing loose shell, but the r‐Cdots consist mainly of the carbon core. Whereas r‐Cdots have a strong blue PL but no apparent ECL response, o‐Cdots exhibit a relatively weak PL and strong ECL emission. These properties allow for selected applications of the Cdots. The r‐Cdots were used in cell imaging with their high PL emission. The o‐Cdots, with their high ECL efficiencies, were selected to sense Cu2+ with Cu2+‐inducing ECL quenching in the o‐Cdots/K2S2O8 system. This work provides the possibility to control the composition of Cdots for selected applications and shows a good way to characterize surface traps of Cdots because ECL is characterized by the surface‐state and PL is mainly related to the core‐state in Cdots.
Illicium Sesquiterpenes: Divergent Synthetic Strategy and Neurotrophic Activity Studies
Authors: Trzoss Lynnie , Xu Jing , Lacoske Michelle H. , Mobley William C. , Theodorakis Emmanuel A. 
Published: March 2013

AbstractMajucin‐type sesquiterpenes from Illicium sp., such as jiadifenolide (2), jiadifenin (3), and (1R,10S)‐2‐oxo‐3,4‐dehydroxyneomajucin (4, ODNM), possess a complex caged chemical architecture and remarkable neurotrophic activities. As such, they represent attractive small‐molecule leads against various neurodegenerative diseases. We present an efficient, enantioselective, and unified synthesis of 2, 3, and 4 and designed analogues that diverge from tetracyclic key intermediate 7. The synthesis of 7 is highlighted by the use of an enantioselective Robinson annulation reaction (construction of the AB rings), a Pd‐mediated carbomethoxylation reaction (construction of the C ring), and a one‐pot oxidative reaction cascade (construction of the D ring). Evaluation of the neurotrophic activity of these compounds led to the identification of several highly potent small molecules that significantly enhanced the activity of nerve growth factor (NGF) in PC‐12 cells. Moreover, efforts to define the common pharmacophoric motif suggest that substitution at the C‐10 center significantly affects bioactivity, while the hemiketal moiety of 2 and 3 and the C‐1 substitution might not be critical to the neurotrophic activity.
The prognostic and predictive value of KRAS oncogene substitutions in lung adenocarcinoma
Authors: Villaruz Liza C. , Socinski Mark A. , Cunningham Diana E. , Chiosea Simion I. , Burns Timothy F. , Siegfried Jill M. , Dacic Sanja 
Published: March 2013

BACKGROUNDThe prognostic and therapeutic implications of the spectrum of v‐Ki‐ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) oncogene substitutions in lung cancer remain poorly understood. The objective of this study was to determine whether KRAS oncogene substitutions differed with regard to prognosis or predictive value in lung adenocarcinoma.METHODSKRAS oncogene substitutions and mutant allele‐specific imbalance (MASI) were determined in patients with lung adenocarcinoma, and the associations with overall survival (OS), recurrence‐free survival (RFS), and chemotherapy interactions were assessed.RESULTSKRAS mutational analysis was performed on 988 lung adenocarcinomas, and 318 KRAS mutations were identified. In this predominantly early stage cohort (78.6% of patients had stage I‐III disease), OS and RFS did not differ according to the type of KRAS substitution (OS, P = .612; RFS, P = .089). There was a trend toward better OS in the subset of patients with KRAS codon 13 mutations (P = .052), but that trend was not significant in multivariate analysis (P = .076). RFS did not differ according to codon type in univariate analysis (P = .322). There was a marked difference in RFS based on the presence of MASI in univariate analysis (P = .004) and multivariate analysis (P = .009). A test for interaction was performed to determine whether the effect of chemotherapy on OS and RFS differed based on KRAS substitution type, codon type, or the presence of MASI. That test indicated that there were no differences in the effects of chemotherapy for any of variables examined.CONCLUSIONSKRAS codon 13 mutations and MASI were identified as candidate biomarkers for prognosis, and it may be useful to incorporate them into prospective studies evaluating novel therapies in KRAS‐mutant lung adenocarcinoma. Cancer 2013;119:2268–2274. © 2013 American Cancer Society.
Global and local parametric diagnosis of analog short‐channel CMOS circuits using homotopy‐simplicial algorithm
Authors: Tadeusiewicz Michał , Hałgas Stanisław 
Published: March 2013

SUMMARYThe paper offers an algorithm for local and global parametric diagnosis in nonlinear analog circuits, including both identification of the faulty parameters and determination their values. The algorithm exploits a nonlinear algebraic type test equations which may possess multiple solutions, corresponding to different sets of the parameters values which meet the test. To find the solutions, the homotopy concept is applied. Since the test equation is not given in explicit analytical form, the simplicial method is used to trace the homotopy path. The proposed approach can be applied to a broad class of analog circuits, including the complementary metal–oxide–semiconductor circuits fabricated in nanometer technology. The developed diagnostic procedure has been implemented in DELPHI, whereas the required by the algorithm repeated circuit analyses are carried out using IsSPICE 4 and both environments have been joined together. For illustration, two numerical examples are given. Copyright © 2013 John Wiley & Sons, Ltd.
Potential Formation in a Bounded Plasma System which is Terminated by an Electron Emitting Floating Collector Studied by a Particle‐in‐Cell Computer Simulation
Authors: Gyergyek T. , Kovačič J. 
Published: March 2013

AbstractPotential formation in one‐dimensional bounded plasma system terminated by a floating, electron emitting collector is studied by particle‐in‐cell (PIC) computer simulation. Attention is focused to the case of rather strong space charge limited emission. Formation of a potential well (virtual cathode) in front of the collector is observed. As emission increases the floating potential of the electrode and the potential of the bottom of the potential well both increase. The floating potential increases faster than the virtual cathode potential and consequently the depth of the potential well in front of the collector increases also. As long as the emission is not to large (up to approximately 40 times the critical emission) the relation between the depth of the potential well and the normalized emission follows a simple logarithmic formula. For larger emissions the depth of the potential well is larger than predicted by the model. It seems that at very large emission the floating potential of the collector might even exceed the zero reference potential of the source electrode. Such phenomenon has been reported by [A. Marek et al. Contrib. Plasma Phys., 48, 491 (2008)], where it was observed that the floating potential of a strongly emissive probe exceeded the plasma potential determined from the knee of the current‐voltage characteristics when the same probe was used as a Langmuir probe. But before this actually happens the simulation breaks down. When positive ions start to be repelled by the positive collector back towards the source the system becomes unstable so that a steady state can not be reached and no results can be read from the output of the simulations. That electron emission may destabilize the sheath in front of it, was found also in Hall thrusters, see e.g. [Daren Yu et al. Phys. Plasmas, 15, 104501, 2008] and [F. Taccogna et al Appl. Phys. Lett., 94, 251502, 2009]. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Discharge Plasma Potential on Diffusion Plasma Parameters Controlled by a Mesh Grid in a Double Plasma Device
Authors: Mishra M. K. , Phukan A. , Chakraborty M. 
Published: March 2013

AbstractThe plasma region under investigation is separated from the discharge region by a mesh grid. Plasma potential and electron number densities and electron temperatures under bi‐Maxwellian approximation for electron distribution function of the multi‐dipole argon plasma are measured. The cold electrons in the diffusion region are produced by local ionization. The hot electrons are the ionizing electrons behaving as Maxwellian. The electron trapping process in the discharge region is produced by potential well due to positive plasma potential with respect to the anode and by a repulsive grid. The dependence of ratios of the density of the hot to the cold electrons NE (=Neh/Nec) and hot to cold electron temperature T(=Teh/Tec) in the diffusion region on the depth of the potential well has been investigated. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized unmixing model for multispectral flow cytometry utilizing nonsquare compensation matrices
Authors: Novo David , Grégori Gérald , Rajwa Bartek 
Published: March 2013

AbstractMultispectral and hyperspectral flow cytometry (FC) instruments allow measurement of fluorescence or Raman spectra from single cells in flow. As with conventional FC, spectral overlap results in the measured signal in any given detector being a mixture of signals from multiple labels present in the analyzed cells. In contrast to traditional polychromatic FC, these devices utilize a number of detectors (or channels in multispectral detector arrays) that is larger than the number of labels, and no particular detector is a priori dedicated to the measurement of any particular label. This data‐acquisition modality requires a rigorous study and understanding of signal formation as well as unmixing procedures that are employed to estimate labels abundance. The simplest extension of the traditional compensation procedure to multispectral data sets is equivalent to an ordinary least‐square (LS) solution for estimating abundance of labels in individual cells. This process is identical to the technique employed for unmixing spectral data in various imaging fields. The present study shows that multispectral FC data violate key assumptions of the LS process, and use of the LS method may lead to unmixing artifacts, such as population distortion (spreading) and the presence of negative values in biomarker abundances. Various alternative unmixing techniques were investigated, including relative‐error minimization and variance‐stabilization transformations. The most promising results were obtained by performing unmixing using Poisson regression with an identity‐link function within a generalized linear model framework. This formulation accounts for the presence of Poisson noise in the model of signal formation and subsequently leads to superior unmixing results, particularly for dim fluorescent populations. The proposed Poisson unmixing technique is demonstrated using simulated 8‐channel, 2‐fluorochrome data and real 32‐channel, 6‐fluorochrome data. The quality of unmixing is assessed by computing absolute and relative errors, as well as by calculating the symmetrized Kullback–Leibler divergence between known and approximated populations. These results are applicable to any flow‐based system with more detectors than labels where Poisson noise is the dominant contributor to the overall system noise and highlight the fact that explicit incorporation of appropriate noise models is the key to accurately estimating the true label abundance on the cells. © 2013 International Society for Advancement of Cytometry
Henry Reaction in Aqueous Media at Neutral pH
Authors: Bora Pranjal P. , Bez Ghanashyam 
Published: March 2013

AbstractAn efficient method for the synthesis of β‐nitro alcohols from nitro alkanes and aldehydes in aqueous phosphate buffer under neutral pH conditions at room temperature is reported. In the case of higher nitro alkanes, the reaction showed very good diastereoselectivity to give syn β‐nitro alcohols in preference to their anti products.
Potentiometric Quantification of the Benzoate Ion in Nonalcoholic Beverages Using a Solid Electrode Modified with a Polypyrrole‐Based Selective Membrane
Authors: Aguilar Lira G. Y. , Álvarez Romero G. A. , de J. Licona Sánchez T. , Páez Hernández M. E. , Galán Vidal C. A. , Romero Romo M. A. 
Published: March 2013

AbstractThis work presents the results obtained on the construction of a potentiometric ion‐selective electrode based on a polypyrrole (PPy) selective membrane to quantify the benzoate ion in nonalcoholic beverages. The electrode modification with benzoate (Benz−1) ion doped‐Ppy was carried out under an imposed potential, while the electrosynthesis optimization was undertaken using the modified Simplex method, such that the film’s sensitivity was maximized toward the benzoate ion. The maximum sensitivity recorded was −52.02±1.55 mV/decade [Benz−1] using a graphite powder‐araldite resin composite electrode. During the modified electrode’s characterization it was found out that the response and drift were relatively short, namely 2 min and 0.4 mV min−1 respectively, within the 7 to 9 pH range, exhibiting a detection limit of 7×10−4 mol L−1 and a quantification range of 3×10−3 at 10−1 mol L−1. Selectivity coefficients were evaluated with the Matched Potential Method obtaining in all cases values much less than 1. The benzoate concentration in commercially available juices and sweetened beverages was evaluated comparing the results obtained with the proposed ion‐selective electrode and those of HPLC, the usually accepted technique. A statistical analysis of the results led to the conclusion that there exists no meaningful difference between the results obtained with both techniques, which shows the usefulness of the ion‐selective electrode to proceed with the quantification in real samples.
Multichannel rivers: their definition and classification
Authors: Carling Paul , Jansen John , Meshkova Lyubov 
Published: March 2013

ABSTRACTThe etymology and historic usage of such terms as ‘anabranch’, ‘anastamose’ and ‘braided’ within river science are reviewed. Despite several decades of modern research to define river channel typologies inclusive of single channels and multiple channel networks, typologies remain ill‐conditioned and consequently ill‐defined. Conventionally employed quantitative planform characteristics of river networks possibly cannot be used alone to define channel types, yet the planform remains a central part of all modern classification schemes, supplemented by sedimentological and other qualitative channel characteristics. Planform characteristics largely have been defined using non‐standardized metrics describing individual network components, such as link lengths, braiding intensity and bifurcation angles, which often fail to separate visually‐different networks of channels. We find that existing typologies remain pragmatically utilitarian rather than fundamentally physics‐based and too often fail to discriminate between two distinctive and important processes integral to new channel initiation and flow‐splitting: (i) in‐channel bar accretion, and (ii) channel avulsion and floodplain excision. It is suggested that, first, if channel planform is to remain central to river typologies, then more rigorous quantitative approaches to the analysis of extended integral channel networks at extended reach scales (rather than network components) are required to correctly determine whether ‘visually‐different’ channel patterns can be discriminated consistently; and, second, if such visually‐different styles do in fact differ in their governing processes of formation and maintenance. A significant question is why do so many seemingly equilibrium network geometries possess a large number of anabranches in excess of predictions from theoretical considerations? The key research frontier with respect to initiating and maintaining multichannel networks remains the understanding and discrimination of accretionary‐bar flow splitting versus avulsive processes. Existing and new knowledge on flow splitting processes needs to be better integrated into channel typologies. Copyright © 2013 John Wiley & Sons, Ltd.
Improvement of streams hydro‐geomorphological assessment using LiDAR DEMs
Authors: Biron Pascale M. , Choné Guénolé , Buffin‐Bélanger Thomas , Demers Sylvio , Olsen Taylor 
Published: March 2013

ABSTRACTHydro‐geomorphological assessments are an essential component for riverine management plans. They usually require costly and time‐consuming field surveys to characterize the spatial variability of key variables such as flow depth, width, discharge, water surface slope, grain size and unit stream power throughout the river corridor. The objective of this research is to develop automated tools for hydro‐geomorphological assessments using high‐resolution LiDAR digital elevation models (DEMs). More specifically, this paper aims at developing geographic information system (GIS) tools to extract channel slope, width and discharge from 1 m‐resolution LiDAR DEMs to estimate the spatial distribution of unit stream power in two contrasted watersheds in Quebec: a small agricultural stream (Des Fèves River) and a large gravel‐bed river (Matane River). For slope, the centreline extracted from the raw LiDAR DEM was resampled at a coarser resolution using the minimum elevation value. The channel width extraction algorithm progressively increased the centerline from the raw DEM until thresholds of elevation differences and slopes were reached. Based on the comparison with over 4000 differential global positioning system (GPS) measurements of the water surface collected in a 50 km reach of the Matane River, the longitudinal profile and slope estimates extracted from the raw and resampled LiDAR DEMs were in very good agreement with the field measurements (correlation coefficients ranging from 0 · 83 to 0 · 87) and can thus be used to compute stream power. The extracted width also corresponded very well to the channel as seen from ortho‐photos, although the presence of bars in the Matane River increased the level of error in width estimates. The estimated maximum unit stream power spatial patterns corresponded well with field evidence of bank erosion, indicating that LiDAR DEMs can be used with confidence for initial hydro‐geomorphological assessments. Copyright © 2013 John Wiley & Sons, Ltd.
On capacity gain of antenna subset selection for multiple antenna multicasting
Authors: Park Seung Young 
Published: March 2013

AbstractIn this letter, we consider the transmit antenna subset selection scheme in multicast channels where the antenna subset is selected to maximise the minimum signal‐to‐noise power ratio among the associated users. Using an asymptotic analysis, the average capacity is derived for the large number of users asymptote under the assumption that the antennas are divided into non‐overlapping subsets, and each of them is independent, identical, spatially uncorrelated, and Rayleigh distributed. The numerical results demonstrate that the asymptotic average capacity is close to the exact capacity when signal‐to‐noise power ratio is not large or the number of users is large. Using this result, we compare the asymptotic average capacity of the selection scheme with that of the open‐loop multiple antenna multicasting scheme, in which only one antenna subset is employed, and its number of antennas is the same as that of the antenna subset of the selection scheme. Specifically, it is shown that the asymptotic capacity gain over the open‐loop scheme is significant when the number of antennas in each antenna subset is small. Copyright © 2013 John Wiley & Sons, Ltd.
Phytosociological behaviour and mineral allocation in Panicum turgidum Forssk. along the coast of the Arabian Gulf, Kuwait
Authors: El‐Sheikh Mohamed A. , Abbadi Ghanim A. , Alatar Abdulrahman A. 
Published: March 2013

AbstractThis study aims at analyzing the phytosociological behaviour, nutrient element allocation and soil‐plant relations of the Panicum turgidum, which inhabits the arid region of Failaka Island and Jal Az‐Zor along the coastal plain of Kuwait. The above and underground parts of P. turgidum, at 21 different sites distributed across two different localities, as well as surrounding soil, were analyzed. TWINSPAN, DCA and CCA multivariate techniques were applied to the plant species and soil data set, with all statistical calculations using SAS software. Multivariate analysis led to the identification of 4 vegetation groups associated with the distribution of P. turgidum. These groups were: Stipagrostis ciliata‐Cakile arabica, Plantago boissieri, Cyperus conglomeratus and Alhagi graecorum. The above and underground parts of P. turgidum in Failaka showed the presence of a wider range of mineral nutrients, whereas in Jal Az‐Zor there was a greater concentration of heavy metals in the analysed plant parts. These results suggested that Failaka, as an isolated island, exhibited better environmental conditions for the growth of P. turgidum with a more efficient uptake, use and recycling of minerals compared with the Jal Az‐Zor in which heavy metals tended to accumulate in the plants and soil (Br, Zn, Fe and Cu). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A high‐order scheme for the incompressible Navier–Stokes equations with open boundary condition
Authors: Sheng Z. , Thiriet M. , Hecht F. 
Published: March 2013

SUMMARYWe present a numerical scheme to solve the incompressible Navier–Stokes equations with open boundary condition. After replacing the incompressibility constraint by the pressure Poisson equation, the key is how to give an appropriate boundary condition for the pressure Poisson equation. We propose a new boundary condition for the pressure on the open boundary. Some numerical experiments are presented to verify the accuracy and stability of scheme. Copyright © 2013 John Wiley & Sons, Ltd.
Rank‐Based Robust Tests for Quantitative‐Trait Genetic Association Studies
Authors: Li Qizhai , Li Zhengbang , Zheng Gang , Gao Guimin , Yu Kai 
Published: March 2013

ABSTRACTStandard linear regression is commonly used for genetic association studies of quantitative traits. This approach may not be appropriate if the trait, on its original or transformed scales, does not follow a normal distribution. A rank‐based nonparametric approach that does not rely on any distributional assumptions can be an attractive alternative. Although several nonparametric tests exist in the literature, their performance in the genetic association setting is not well studied. We evaluate various nonparametric tests for the analysis of quantitative traits and propose a new class of nonparametric tests that have robust performance for traits with various distributions and under different genetic models. We demonstrate the advantage of our proposed methods through simulation study and real data applications.