bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variability of fMRI‐response patterns at different spatial observation scales
Authors: Ball Tonio , Breckel Thomas P.K. , Mutschler Isabella , Aertsen Ad , Schulze‐Bonhage Andreas , Hennig Jürgen , Speck Oliver 
Published: March 2011

AbstractFunctional organization units of the cerebral cortex exist over a wide range of spatial scales, from local circuits to entire cortical areas. In the last decades, scale‐space representations of neuroimaging data suited to probe the multi‐scale nature of cortical functional organization have been introduced and methodologically elaborated. For this purpose, responses are statistically detected over a range of spatial scales using a family of Gaussian filters, with small filters being related to fine and large filters—to coarse spatial scales. The goal of the present study was to investigate the degree of variability of fMRI‐response patterns over a broad range of observation scales. To this aim, the same fMRI data set obtained from 18 subjects during a visuomotor task was analyzed with a range of filters from 4‐ to 16‐mm full width at half‐maximum (FWHM). We found substantial observation‐scale‐related variability. For example, using filter widths of 6‐ to 8‐mm FWHM, in the group‐level results, significant responses in the right secondary visual but not in the primary visual cortex were detected. However, when larger filters were used, the responses in the right primary visual cortex reached significance. Often, responses in probabilistically defined areas were significant when both small and large filters, but not intermediate filter widths were applied. This suggests that brain responses can be organized in local clusters of multiple distinct activation foci. Our findings illustrate the potential of multi‐scale fMRI analysis to reveal novel features in the spatial organization of human brain responses. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc.
Further Alkaloids from the Fruits of Daphniphyllum longeracemosum
Authors: Yang Ting‐Quan , Di Ying‐Tong , He Hong‐Ping , Zhang Qiang , Zhang Yu , Hao Xiao‐Jiang 
Published: March 2011

AbstractThree new Daphniphyllum alkaloids, daphlongeranines C–E (1–3), along with 13 known ones, were isolated from the fruits of Daphniphyllum longeracemosum. Their structures were elucidated on the basis of extensive spectroscopic analyses, especially 2D‐NMR experiments.
Two New Cytotoxic Naphthoquinones from Didymocarpus hedyotideus
Authors: Xiao Xi‐Bin , Lin Yue‐Xing , Xu Geng‐Bo , Gong Xu‐Bo , Gu Ying , Tong Jie‐Feng , Yang Jing 
Published: March 2011

AbstractA new naphthoquinone, 6‐hydroxy‐α‐dunnione (1) and a new binaphthoquinone, methyl 1,1′,4,4′‐tetrahydro‐3‐hydroxy‐1,1′,4,4′‐tetraoxo[2,2′‐binaphthalene]‐3′‐carboxylate (2), along with ten known compounds, including naphthoquinones, anthraquinones, and phenylethanoid glucosides, were isolated from the roots of Didymocarpus hedyotideus Chun. Their structures were identified by spectroscopic analyses, particularly 1D‐ and 2D‐NMR spectroscopy. The cytotoxic activities of the two new naphthoquinones were also evaluated.
Mechanism of (Salen)manganese(III)‐Catalyzed Oxidation of Aryl Phenyl Sulfides with Sodium Hypochlorite
Authors: Chellamani Arunachalam , Harikengaram Sivalingam 
Published: March 2011

AbstractThe oxidation of 4‐substituted phenyl phenyl sulfides was carried out with several oxo(salen)manganese(V) complexes in MeCN/H2O 9 : 1. The kinetic data show that the reaction is first‐order each in the oxidant and sulfide. Electron‐attracting substituents in the sulfides and electron‐releasing substituents in salen of the oxo(salen)manganese(V) complexes reduce the rate of oxidation. A Hammett analysis of the rate constants for the oxidation of 4‐substituted phenyl phenyl sulfides gives a negative ρ value (ρ=−2.16) indicating an electron‐deficient transition state. The log k2 values observed in the oxidation of each 4‐substituted phenyl phenyl sulfide by substituted oxo(salen)manganese(V) complexes also correlate with Hammett σ constants, giving a positive ρ value. The substituent‐, acid‐, and solvent‐effect studies indicate direct O‐atom transfer from the oxidant to the substrate in the rate‐determining step.
Efficient and Chemoselective Methods for the Synthesis of Some Isobenzofuran and Spiro[isobenzofuran‐1,2′‐pyrrole] Derivatives
Authors: Mohammadizadeh Mohammad R. , Firoozi Neda , Aradeh R. 
Published: March 2011

AbstractAn efficient and practical one‐pot procedure for the direct chemoselective synthesis of isobenzofuran and spiro[isobenzofuran‐1,2′‐pyrrole] derivatives is developed via oxidative cleavage of 3a,8b‐dihydroxyindeno[1,2‐b]pyrrol‐4‐ones with Pb(OAc)4 at room temperature.
Terpenes from Schisandra sphenanthera
Authors: Jiang Yan , Yang Guang‐Zhong , Chen Yu , Liao Mao‐Chuan , Liu Xiang‐Ming , Chen Su , Liu Lu , Lei Xin‐Xiang 
Published: March 2011

AbstractOne novel, highly oxygenated nortriterpenoid, schintrilactone C (1), and four known compounds, 2–5, were isolated from the rattan of Schisandra sphenanthera. Their structures were determined by analysis of 1D‐ and 2D‐NMR spectroscopic data. Schintrilactone C is the third example of wuweiziartane‐type nortriterpenoids, bearing a modified five‐membered D ring, a δ‐lactone E ring, and a spirocyclic moiety in the side chain at C(13).
N‐Bromosuccinimide (NBS): A Novel and Efficient Catalyst for the Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthenes under Solvent‐Free Conditions
Authors: Habibzadeh Setareh , Ghasemnejad Hassan , Faraji Mohammad 
Published: March 2011

AbstractA novel procedure for the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes through one‐pot condensation of naphthalen‐2‐ol with arenecarbaldehydes in the presence of N‐bromosuccinimide (NBS) as catalyst under solvent‐free conditions is described.
On the Reactivity of (−)‐(R)‐Carvone and (−)‐4aα,7α,7aβ‐Nepetalactone: Synthesis of New Heterocycles
Authors: El Mebtoul Aziz , Rouani Mohamed , Chammache Malika , Bouidida Houcine , Ilidrissi Abdelkader 
Published: March 2011

AbstractThe 1,3‐dipolar cycloaddition of 4‐chlorobenzonitrile oxide to the unsaturated system of (−)‐(R)‐carvone occurred exclusively at C(8) to give a new isoxazoline derivative. This derivative reacts with NH2OH to yield a new heterocycle, observed for the first time. On the other hand, the addition of 4‐chlorobenzonitrile oxide to the unsaturated lactone (−)‐4aα,7α,7aβ‐nepetalactone gave, in a good yield, also a new heterocycle, again obtained for the first time. The terpenoid (−)‐(R)‐carvone and iridoid (−)‐4aα,7α,7aβ‐nepetalactone were isolated from Moroccan species Mentha viridis (L.) and Nepeta tuberosa (L.), respectively. The new heterocycles obtained were identified by combination of chromatographic and spectroscopic methods.
Two New Alkaloids from the Aerial Part of Peganum nigellastrum
Authors: Yang Fei , Chen Rong , Feng Lin , Li Hai‐Dao , Zhang Hua 
Published: March 2011

AbstractTwo new alkaloids, pegamine β‐D‐glucopyranoside (1) and 2‐deoxypeganylacetic acid (2), together with the novel 3,4‐dihydro‐4‐hydroxynaphthalene‐2‐carboxylic acid (3), were isolated from the aerial part of Peganum nigellastrum. The structures of these compounds were elucidated on the basis of spectroscopic analyses, including 1D‐ and 2D‐NMR, and ESI‐MS/MS.
Kadsufolins A – D and Related Cytotoxic Lignans from Kadsura oblongifolia
Authors: Huang Zehao , Lu Yan , Liu Yinan , Bastow Kenneth F. , Lee Kuohsiung , Chen Daofeng 
Published: March 2011

AbstractKadsufolins A–D (1–4, resp.), four new dibenzocyclooctane‐type lignans, were isolated from the roots and stems of Kadsura oblongifolia, together with eleven known lignans. Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR techniques. The compounds were also evaluated for cytotoxic activity against human tumor cell lines A549 (lung carcinoma), DU145 (prostate carcinoma), KB (epidermoid carcinoma of the nasopharynx), and HCT‐8 (ileocecal carcinoma). Kadsufolin A (1), kadsufolin D (4), angeloylbinankadsurin A, and heteroclitin B were found to show cytotoxic activities against A549, DU145, KB and HCT‐8 with GI50 values of 5.1–20.0 μg/ml.
One‐Pot Synthesis of Pyrimidines via Cyclocondensation of β‐Bromovinyl Aldehydes with Amidine Hydrochlorides
Authors: Yan Shengjiao , Tang Yajuan , Yu Fuchao , Lin Jun 
Published: March 2011

AbstractA series of pyrimidines were prepared by cyclocondensation of β‐bromovinyl aldehydes with amidine hydrochlorides in the presence of Et3N in excellent yields (74–95%).
Note: Helix or No Helix of β‐Peptides Containing β3hAla(αF) Residues?
Authors: Jaun Bernhard , Seebach Dieter , Mathad Raveendra I. 
Published: March 2011

AbstractA remote 4J(F,H) coupling (FC(α)C(O)NH) of up to 4.2 Hz in α‐fluoro amides with antiperiplanar arrangement of the CF and the CO bonds (dihedral angle FCCO ca. 180°) confirms that previous NMR determinations, using the XPLOR‐NIH procedure, of the secondary structures of β‐peptides containing β3hAla(αF) and β3hAla(αF2) residues were correct. In contrast, molecular‐dynamics (MD) simulations, using the GROMOS program with the 45A3 force field, led to an incorrect conclusion about the relative stability of secondary structures of these β‐peptides. The problems encountered in NMR analyses and computations of the structures of backbone‐F‐substituted peptides are briefly discussed.
The influence of water retention curve hysteresis on the stability of unsaturated soil slopes
Authors: Ma Kuo‐Chen , Tan Yih‐Chi , Chen Chu‐Hui 
Published: March 2011

AbstractHysteresis is a common feature exhibited in hydraulic properties of an unsaturated soil. The movement of wetting front and the hysteresis effect are important factors which impact the shear strength of the unsaturated soil and the mechanics of shallow landslides. These failures are mainly triggered by the deepening of the wetting front accompanied by a decrease in matric suction induced by infiltration. This research establishes a method for determining a stability analysis of unsaturated infinite soil slopes, integrating the influence of infiltration and the water retention curve hysteresis. Furthermore, the present stability analysis method including the infiltration model and the advanced Mohr–Coulomb failure criterion calculates the variations of the safety factor (FS) in accordance with different slope angle, depth and hydrological processes. The experimentally measured data on the effect of hysteresis are also carried out for comparison. Numerical analyses, employing both wetting and drying hydraulic behaviour of unsaturated soil, are performed to study the difference in soil‐water content as observed in the experiments. The simulating approximations also fully responded to the experimental data of sand box. The results suggest that the hysteresis behaviour affect the distribution of soil‐water content within the slope indeed. The hysteresis made the FS values a remarkable recovery during the period of non‐rainfall in a rainfall event. The appropriate hydraulic properties of soil (i.e. wetting or drying) should be used in accordance with the processes that unsaturated soil actually experience. This method will enable us to acquire more accurate matric suction head and the unsaturated soil‐shear strength as it changes with the hysteretic flow, in order to calculate into the stability analysis of shallow landslides. An advanced understanding of the process mechanism afforded by this method is critical to realizing a reliable and appropriate design for slope stabilization. It also offers some immediate reference information to the disaster reduction department of the government. Copyright © 2011 John Wiley & Sons, Ltd.
On‐demand drug delivery from self‐assembled nanofibrous gels: A new approach for treatment of proteolytic disease
Authors: Vemula Praveen Kumar , Boilard Eric , Syed Abdullah , Campbell Nathaniel R. , Muluneh Melaku , Weitz David A. , Lee David M. , Karp Jeffrey M. 
Published: March 2011

AbstractLocal delivery of drugs offers the potential for high local drug concentration while minimizing systemic toxicity, which is often observed with oral dosing. However, local depots are typically administered less frequently and include an initial burst followed by a continuous release. To maximize efficiency of therapy, it is critical to ensure that drug is only released when needed. One of the hallmarks of rheumatoid arthritis, for example, is its variable disease activity consisting of exacerbations of inflammation punctuated by periods of remission. This presents significant challenges for matching localized drug delivery with disease activity. An optimal system would be nontoxic and only release drugs during the period of exacerbation, self‐titrating in response to the level of inflammation. We report the development of an injectable self‐assembled nanofibrous hydrogel, from a generally recognized as safe material, which is capable of encapsulation and release of agents in response to specific enzymes that are significantly upregulated in a diseased state including matrix metalloproteinases (MMP‐2 and MMP‐9) and esterases. We show that these self‐assembled nanofibrous gels can withstand shear forces that may be experienced in dynamic environments such as joints, can remain stable following injection into healthy joints of mice, and can disassemble in vitro to release encapsulated agents in response to synovial fluid from arthritic patients. This novel approach represents a next‐generation therapeutic strategy for localized treatment of proteolytic diseases. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Dietary cadmium exposure and fracture incidence among men: A population-based prospective cohort study
Authors: Thomas Laura DK , Michaëlsson Karl , Julin Bettina , Wolk Alicja , Åkesson Agneta 
Published: March 2011

Abstract
Cadmium is an osteotoxic metal present in food. It causes multiple fractures in those highly exposed and is associated with reduced bone mineral density at considerably lower exposures. Little is known about fracture rates following low-level cadmium exposure. We assessed the associations between dietary cadmium exposure and fracture incidence.
Within a population-based prospective cohort of 22,173 Swedish men, we estimated individual dietary cadmium exposure using food frequency questionnaire data and levels of cadmium in food. The average intake was 19 µg/day. Hazard ratios (HRs) for any fracture and hip fracture were estimated using Cox's regression. During 10 years of follow-up, we ascertained 2183 cases of any fracture and 374 hip fractures by computerized linkage of the cohort to registry data. Multivariable-adjusted dietary cadmium intake was associated with a statistically significant 19% [HR = 1.19, 95% confidence interval (CI) 1.06–1.34] higher rate of any fracture comparing highest tertile with lowest (p ≤ .01 for trend). Moreover, men in the highest tertile of dietary cadmium and lowest tertile of fruit and vegetable consumption had a 41% higher rate of any fracture compared with contrasting tertiles. Hip fracture rates also were higher in the highest tertile of cadmium intake but only statistically significant among never smokers (HR = 1.70, 95% CI 1.04–2.77). Our results indicate that dietary cadmium exposure at general population levels is associated with an increased rate of fractures among men. This association was independent of smoking and was most pronounced among men with low fruit and vegetable consumption. © 2011 American Society for Bone and Mineral Research.
Novel optical techniques for measurements of light extinction, scattering and absorption by single aerosol particles
Authors: Miles R.E.H. , Carruthers A.E. , Reid J.P. 
Published: March 2011

AbstractAerosol particles play important roles in a broad range of scientific disciplines, from atmospheric chemistry and physics, to the delivery of fuels for combustion and drugs to the lungs, and extending to industrial processes such as spray drying. Measurements of the light extinction, scattering and absorption by ensembles of aerosol particles can be used to non‐intrusively characterise aerosol particle samples. However, such measurements often lead to ambiguity in interpreting the properties and processes occurring on individual particles. In this review, recent developments in the use of laser based techniques to isolate and manipulate single particles and to characterise them will be highlighted. In particular, the use of cavity ring down spectroscopy, Bessel beams and optical tweezers for investigating light extinction, scattering and absorption, respectively, will be considered. The prospects for using optical techniques to interrogate the fundamental processes occurring in aerosol at the single particle level are discussed.
Advanced interferometry, quantum optics and optomechanics in gravitational wave detectors
Authors: McClelland D.E. , Mavalvala N. , Chen Y. , Schnabel R. 
Published: March 2011

AbstractCurrently operating laser interferometric gravitational wave detectors are limited by quantum noise above a few hundred Hertz. Detectors that will come on line in the next decade are predicted to be limited by quantum noise over their entire useful frequency band (from 10 Hz to 10 kHz). Further sensitivity improvements will, therefore, rely on using quantum optical techniques such as squeezed state injection and quantum non‐demolition, which will, in turn, drive these massive mechanical systems into quantum states. This article reviews the principles behind these optical and quantum optical techniques and progress toward there realization.
The Schur multiplicative and harmonic convexities of the complete symmetric function
Authors: Chu Y.‐M. , Wang G.‐D. , Zhang X.‐H. 
Published: March 2011

AbstractThis paper investigates the Schur multiplicative and harmonic convexities of the complete symmetric function \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$F_n(x,r)=\sum _{i_1+i_2+\cdots +i_n=r}x_1^{i_1}x_2^{i_2}\ldots x_n^{i_n}$\end{document} and the function \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\varphi _n(x,r)=\frac{F_n(x,r)}{F_n(x,r-1)}$\end{document}, where i1, i2, …, in are nonnegative integers and r ⩾ 1. As applications, some analytic inequalities are established by use of the theory of majorization. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Limit point, strong limit point and Dirichlet conditions for Hamiltonian differential systems
Authors: Qi Jiangang , Wu Hongyou 
Published: March 2011

AbstractThis paper deals with singular Hamiltonian differential systems. Three conditions on the asymptotic behavior or square integrability of their maximal domain functions at a singular end point are studied: the limit point condition, the strong limit point condition and the Dirichlet condition. The equivalence between the limit point and strong limit point conditions is established for a class of such systems, and for another class, the three conditions are shown to imply each other. As an application, two unified descriptions of the Friedrichs extension for some systems in the second class are obtained. A key feature of the descriptions is: they do not use the deficiency indices of the systems. Several illustrating examples are presented. In particular, two simple descriptions of the Friedrichs extension for a family of Schrödinger operators with singular potentials are achieved. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Traces of Besov and Triebel‐Lizorkin spaces on domains
Authors: Schneider Cornelia 
Published: March 2011

AbstractWe determine the trace of Besov spaces \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\mathfrak {B}^s_{p,q}(\Omega )$\end{document} and Triebel‐Lizorkin spaces \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\mathfrak {F}^s_{p,q}(\Omega )$\end{document}, characterized via atomic decompositions, on the boundary of Ck domains Ω for parameters 0 < p, q ⩽ ∞ and \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s>\frac{1}{p}$\end{document}. The limiting case \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s=\frac{1}{p}$\end{document} is investigated as well. In terms of Besov spaces our results remain valid for the classical spaces Bsp,q(Ω) defined via differences. Furthermore, we include some density assertions, which imply that the trace does not exist when \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s<\frac{1}{p}$\end{document}. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Conformational and configurational analysis of an N,N carbonyl dipyrrinone‐derived oximate and nitrone by NMR and quantum chemical calculations
Authors: Walton Ian , Davis Marauo , Yang Liu , Zhang Yong , Tillman Destin , Jarrett William L. , Huggins Michael T. , Wallace Karl J. 
Published: March 2011

AbstractThe geometries and relative energies of new N,N carbonyl dipyrrinone‐derived oxime molecules (E/Z‐s‐cis 4a and E/Z‐s‐cis 4b) have been investigated. The calculated energies, molecular geometries, and 1H/13C NMR chemical shifts agree with experimental data, and the results are presented herein. The E‐s‐cis conformations of 4a and 4b and the Z‐s‐cis conformation of 5b were found to be the thermodynamically most stable isomers with the oxime hydrogen atom or the methyl functional group adopting an anti‐orientation with respect to the dipyrrinone group. This conformation was unambiguously supported by a number of 2D NMR experiments. Copyright © 2011 John Wiley & Sons, Ltd.
Magnetic poly(lactide‐co‐glycolide) and cellulose particles for MRI‐based cell tracking
Authors: Nkansah Michael K. , Thakral Durga , Shapiro Erik M. 
Published: March 2011

AbstractBiodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide‐co‐glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil‐in‐water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r values per millimole of iron (399 sec−1 mM−1 for cellulose and 505 sec−1 mM−1 for PLGA), micron‐sized PLGA particles had a much higher r per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA‐based particles) or long‐term (cellulose‐based particles) experiments. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.