bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noninvasive Imaging Surrogate of Angiogenesis in Osteosarcoma
Authors: Bajpai Jyoti , Gamanagatti Shivanand , Sharma Mehar C. , Kumar Rakesh , Vishnubhatla Sreenivas , Khan Shah Alam , Rastogi Shishir , Malhotra Arun , Bakhshi Sameer 
Published: November 2009

AbstractPurposeMeasurement of tumor angiogenesis by qualitative analysis of dynamic contrast enhanced‐magnetic resonance imaging (DCE‐MRI), and its association with diffusion‐weighted (DW)‐MRI and glucose metabolism using positron emission tomography‐computerized tomography (PET‐CT) scan has not been explored in osteosarcoma. Present study was aimed to evaluate the potential of these surrogates.Patients And MethodsThirty‐one treatment naive patients with osteosarcoma underwent MRI and PET‐CT preceding and following three cycles of neoadjuvant chemotherapy (NACT) and surgery. Time intensity curves (TICs) representing low microvascular permeability is persistent type while that of high permeability are plateau and washout types. Vascular endothelial growth factor (VEGF) expression was assessed in biopsy and resected specimens by immunohistochemistry. The sample was considered VEGF positive when intensive positive staining of VEGF was observed in >10% of the tumor cells in biopsy or resection specimens.ResultsTIC could correctly identify all 28 VEGF positive samples at baseline and 24/25 (96%) of VEGF positive samples and 5/6 (83%) of VEGF negative samples after NACT. The change in curve pattern from washout/plateau to persistent type was in agreement with corresponding decrease in microvascular permeability, that is, VEGF expression. For persistent type of TIC, mean change in VEGF was 73.3 ± 43.2% and for plateau and washout type of TIC it was 19.54 ± 45% and 16.66 ± 28.86%, respectively (P ≤ 0.04). VEGF expression did not correlate with DW‐MRI and PET‐CT parameters.ConclusionThis study suggests an important role of DCE‐MRI as a noninvasive imaging surrogate of tumor angiogenesis in osteosarcoma based on visual inspection of TIC. Pediatr Blood Cancer 2010;54:526–531. © 2009 Wiley‐Liss, Inc.
User and carer views of CAMHS intensive home treatment service in Bradford
Authors: Rani Jhansi , Prosser Anthea , Worrall‐Davies Anne , Kiernan Katy , Hewson Lesley 
Published: November 2009

AbstractWe report the views of young people and their families who used an innovative, intensive home‐based child and adolescent mental health service. We interviewed a sample of young people and their parents, who had used the service using a semi‐structured interview designed to encourage reflection on the intensive home‐based service. Interviews were recorded, transcribed and framework analysis undertaken. Key themes are discussed in the context of current strategic developments of children's services. We concluded that it is important for families to know what services are available, and feel that they have choice in treatment plans. Both positive and negative impacts on family life in caring for a young person with mental illness at home emerged as key themes. Copyright © 2009 John Wiley & Sons, Ltd.
Embodied transnationalism: bodies in transnational spaces
Authors: Dunn Kevin 
Published: November 2009

AbstractTransnationalism has become a popular concept within migration studies and human geography. A series of concerns have been raised about the early use of the term, mostly prompted by an exaggerated characterisation of mobility. Adopting an embodied approach to the study of transnationalism is a powerful corrective to the dangers of exaggerating mobility and footloosedness. When the scale of analysis is upon migrants rather than migration flows, and upon transnationals rather than upon transnationalism, a much more complicated and realistic picture emerges. Transnationals are simultaneously mobile and emplaced. And the extent of choice and compulsion (of both mobility and sedentariness) is uneven across racialised axes, birthplace, gender, and disability. At the embodied scale the affective and emotional geographies of transnationalism are more palpable. Importantly, an embodied analysis of transnationalism reveals the ever‐present valency of place. Copyright © 2009 John Wiley & Sons, Ltd.
The biophysical and geographical correlates of child malnutrition in Africa
Authors: de Sherbinin Alex 
Published: November 2009

AbstractHunger is a major problem in sub‐Saharan Africa, and unlike other world regions the problem seems to be worsening. This paper seeks to determine if, when controlling for income and the health conditions, biophysical and geographical variables help to explain variation in the rates of child malnutrition. The literature on this subject is inconclusive precisely because the survey data, upon which most studies of malnutrition rely, rarely include variables that measure these factors. Examples of biophysical and geographic factors often cited in the literature include the balance of rainfall to evapotranspiration, the productivity of agricultural lands, distance to urban areas, topography, the frequency of drought, malaria endemicity, and market access through road networks. This paper introduces these variables into an analysis of 367 sub‐national units in Africa based on household demographic survey strata. Running a spatial error model, and controlling for income, only three variables were found to be significantly correlated with child malnutrition: drought prevalence, the percentage of households with piped water, and diarrheal disease prevalence. This contrasts with the findings of earlier studies that sought to introduce similar biophysical/geographical variables into analyses of child malnutrition and mortality, as well as with ordinary least squares regression results presented in this paper, which found much larger sets of biophysical and geographical variables to be significantly correlated with malnutrition, thus highlighting the importance of addressing spatial autocorrelation in studies of this kind. The paper concludes with policy recommendations and a brief assessment of the strengths and shortcomings of continental scale analyses on the drivers of hunger and poverty. Copyright © 2009 John Wiley & Sons, Ltd.
Novel metal‐[metal oxide]‐nonmetal sandwich‐like superalkali compounds Li3OMC5H5 (M = Be, Mg, and Ca): How to increase the aromaticity of Li ring?
Authors: Wang Yin‐Feng , Chen Wei , Yu Guang‐Tao , Li Zhi‐Ru , Sun Chia‐Chung 
Published: November 2009

AbstractThe structures of novel metal‐[metal oxide]‐nonmetal sandwich‐like superalkali compounds, that is, H‐ and T‐shaped Li3OMC5H5 (M = Be, Mg, and Ca), with all the real frequencies are obtained for the first time at the MP2/6‐311+G(2d, p) level. For M = Be, the T‐shaped isomer is more stable than the H‐shaped one, but the H‐shaped isomer is more stable than the T‐shaped one for M = Mg and Ca. The natural bond orbital analysis indicates that these compounds are complex zwitterions and can be denoted as (Li3)+(O2−M2+)(C5H5)− with two aromatic rings (Li and C5H). Four factors to increase the nucleus‐independent chemical shift (NICS) of Li ring in Li3OMC5H5 systems are found. (1) Replacing the T‐shaped structure with parallel Li and C5H ring by the corresponding H‐shaped structure with perpendicular Li and C5H ring, the NICS value considerably increases from −7.8 ∼ −8.2 to −22.2 ∼ −43.4 ppm. (2) The existence of the neighboring alkaline earth metal oxide subunit evidently increases the NICS in H‐shaped structures from about −11.1 to −16.1 ∼ −37.0 ppm. (3) Based on the finding that the alkaline earth atomic number dependence of the aromaticity of Li ring, the larger atomic number increases the NICS value. (4) The end C5H subunit increases the NICS value. For example, the increase is −6.4 ppm for H‐shaped Li3OCaC5H5. In addition, the expected out‐of‐plane σ‐aromaticity of Li ring is not exhibited, in contrast to that in the sandwich‐like structure of Li3OLi3 (Chen et al., J Chem Phys, 2005, 123, 164306), but the in‐plane σ‐aromaticity of it is increased. Why? This is because (1) the size of the OM subunit near the Li ring is small, and (2) the large‐sized C5H subunit is far from the Li ring. For these Li3OMC5H5, the H‐shaped structure exhibits electride characteristics, and the T‐shaped structure with lithium anion exhibits alkalide characteristics. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Ground state for two‐electron and electron‐muon three‐body atomic systems
Authors: Rodriguez K. V. , Ancarani L. U. , Gasaneo G. , Mitnik D. M. 
Published: November 2009

AbstractIn this article, the angular correlated configuration interaction method previously introduced by some of the authors is extended to three‐body atomic systems with general masses. A recently proposed angularly correlated basis set is used to construct ground state wave functions which: (i) satisfy exactly Kato cusp conditions at the two‐body coalescence points; (ii) have only linear coefficients; and (iii) show a fast convergency rate for the energy. The efficiency of the construction is illustrated by the study of the negatively charged hydrogen‐like systems (∞H−, T−, D−, 1H−, and Mu−), neutral helium‐like systems (e−e− ∞He+2,e−e− 4He+2, e−e− 3He+2, e−μ− ∞He+2, e−μ −4He+2, and e−μ− 3He+2), and positively charged lithium‐like systems (e−e− ∞Li+3, e−e− 7Li+3, e−e− 6Li+3, e−μ− ∞Li+3, e−μ− 7Li+3, and e−μ− 6Li+3). The ground state energies and other mean values are compared with those given in the literature, when available. Wave functions with a moderate number of (20 maximum) linear coefficients are given explicitly; they are sufficiently simple and accurate to be used in practical calculations of atomic collision in which multidimensional integrations are involved. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Geometrical properties of nodal surfaces of many‐electron wave functions
Authors: Chuvylkin Nikolai D. , Smolenskii Evgenii A. , Molchanova Marina S. , Zefirov Nikolai S. 
Published: November 2009

AbstractHypothesis of the exclusion of equipotential surfaces for many‐electron wave functions (MWF) has been enunciated. This hypothesis clarifies the physical meaning of the Pauli exclusion principle and opens the way for future progress of new quantum‐chemical methods for the construction of approximate MWFs differing from the traditional Hartree–Fock approximation. The equipotential surface exclusion principle has been tested on traditional representative “test systems” of quantum mechanics: the helium atom, the lithium atom, and the hydrogen molecule. Judging by the results of these tests, the use of the suggested approach can lead to a considerable increase in the efficiency of high‐accuracy quantum‐chemical calculations. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical study on second‐order nonlinear optical properties of spin crossover Fe(III) phenolate‐pyridyl Schiff base complexes
Authors: Zhao Hai‐Bo , Sun Shi‐Ling , Qiu Yong‐Qing , Liu Chun‐Guang , Su Zhong‐Min 
Published: November 2009

AbstractThe density functional and ab initio theory were used to investigate the second‐order nonlinear optical (NLO) properties of Schiff base ligands, open‐shell Fe(III), and closed‐shell Ni(II) complexes. The effect of the metal center in complexes is thus manifold: it templates the formation of acentric structures, imparts high thermal stability to the chelate ring, and display higher second‐order NLO response than their ligands. The second‐order NLO response of metal complexes are intensively sensitive to the exchange donor/acceptor because the differences of the extent of charge separation and the intraligand charge transfer processes. Thus, substituted metal complexes could realize “switches on” the second‐order NLO response by exchange donor/acceptor. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
[Fe‐Fe]‐hydrogenase reactivated by residue mutations as bridging carbonyl rearranges: A QM/MM study
Authors: Motiu Stefan , Gogonea Valentin 
Published: November 2009

AbstractIn this work, we found aqueous enzyme phase reaction pathways for the reactivation of the exogenously inhibited [Fe‐Fe]‐hydrogenases by O2, or OH−, which metabolizes to H2O (Dogaru et al., Int J Quantum Chem 2008, 108; Motiu et al., Int J Quantum Chem 2007, 107, 1248). We used the hybrid quantum mechanics/molecular mechanics (QM/MM) method to study the reactivation pathways of the exogenously inhibited enzyme matrix. The ONIOM calculations performed on the enzyme agree with experimental results (Liu et al., J Am Chem Soc 2002, 124, 5175), that is, wild‐type [Fe‐Fe]‐hydrogenase H‐cluster is inhibited by oxygen metabolites. An enzyme spherical region with a radius of 8 Å (from the distal iron, Fed) has been screened for residues that prevent H2O from leaving the catalytic site and reactivate the [Fe‐Fe]‐hydrogenase H‐cluster. In the screening process, polar residues were removed, one at a time, and frequency calculations provided the change in the Gibbs' energy for the dissociation of water (due to their deletion). When residue deletion resulted in significant Gibbs' energy decrease, further residue substitutions have been carried out. Following each substitution, geometry optimization and frequency calculations have been performed to assess the change in the Gibbs' energy for the elimination of H2O. Favorable thermodynamic results have been obtained for both single residue removal (ΔGΔGlu374 = −1.6 kcal/mol), single substitution (ΔGGlu374His = −3.1 kcal/mol), and combined residue substitutions (ΔGArg111Glu;Thr145Val;Glu374His;Tyr375Phe = −7.5 kcal/mol). Because the wild‐type enzyme has only an endergonic step to overcome, that is, for H2O removal, by eliminating several residues, one at a time, the endergonic step was made to proceed spontaneously. Thus, the most promising residue deletions which enhance H2O elimination are ΔArg111, ΔThr145, ΔSer177, ΔGlu240, ΔGlu374, and ΔTyr375. The thermodynamics and electronic structure analyses show that the bridging carbonyl (COb) of the H‐cluster plays a concomitant role in the enzyme inhibition/reactivation. In gas phase, COb shifts towards Fed to compensate for the electron density donated to oxygen upon the elimination of H2O. However, this is not possible in the wild‐type enzyme because the protein matrix hinders the displacement of COb towards Fed, which leads to enzyme inhibition. Nevertheless, enzyme reactivation can be achieved by means of appropriate amino acid substitutions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical study on electronic structure of (CNC)Fe_2N2 and its N2 elimination mechanism
Authors: Zhang Xiang 
Published: November 2009

AbstractThe density function theory (DFT) is to elucidate the electronic structure of bis(dinitrogen) Fe(0) complex, (CNC)Fe_2N2, and its N2 elimination mechanism. (CNC)Fe_2N2 has a low‐spin singlet (S = 0) ground state with a distorted square pyramidal structure. Fragment orbital interaction analysis yields total occupancy of π* orbitals (LUF(4)O and LUF(4)O−1) of apical N3N4 is 0.188 while that of basal N1N2 is 0.187 in S0(CNC)Fe_2N2, suggesting nearly the same activation extent for both basal and apical N2 ligands. The lowest‐lying triplet state T1 (3‐A′) has a repulsive potential energy surface along the FeN3 bong length by PBE functional, while a minimum on T2 state (3‐A″) with higher energy is found by B3LYP functional. The nonadiabatic N2 elimination mechanism of (CNC)Fe_2N2 involves an S0‐T1 states crossing, which lowers the activation energy to 9.7 kcal/mol and produces high‐spin intermediate (CNC)FeN2. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The proton‐coupled proton transfer mechanism, H2O catalysis, and hydrogen tunneling effects in the reaction of HNCH2 with HCOOH in the interstellar medium
Authors: Xu Sichuan , Deng Shengrong , Ma Liying , Shi Qiang , Ge Maofa , Zhang Xingkang 
Published: November 2009

AbstractThe reaction HNCH2 + HCOOH → H2NCH2COOH is supposed to be an important reaction related to the possible origin of amino acids on the early Earth. We find that it has an energy barrier of 87.37 kcal mol−1 obtained with MP2/6‐311+G** in the gas phase, but it is likely enhanced to occur in the interstellar medium (ISM) through a proton‐coupled proton transfer reaction, initiated by HNCH2 coupled with H2+, H3+, or H3+O. H2+, H3+, and H3+O serve as a donor of energy in the coupled reactions. H+, which is a key species to the coupled reactions, further, plays a catalytic role in reducing a barrier up to 14.14 kcal mol−1. In the coupled reaction with H3+O, H2O, which can seize, transport, and deliver a proton from HCOOH to H2NCH2+, reduces a barrier up to 14.96 kcal mol−1. A significant hydrogen‐tunneling pathway is predicted by the temperature dependences of kHCVT/SCT, calculated using the small curvature tunneling (SCT) approximation and canonical variational transition state theory (CVT). Hydrogen tunneling is another important mechanism to make the reaction happen in the ISM. The achieved results can be applied to discuss the origin of amino acids from the materials of the Earth itself. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Can methylene amidogene and its isomers be formed by a concerted reaction?
Authors: Metropoulos Aristophanes 
Published: November 2009

AbstractWe have explored the possibility of occurrence of the concerted formation of the methylene amidogene radical and its cis isomer from H2 and CN at energy regimes of over 60 kcal/mol relative to the ground state of the radical. We have concluded that for the cases of parallel and perpendicular orientations of H2 and CN, a concerted reaction is possible in principle provided that H2 is vibrationally excited. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Bond percolation with attenuation in high dimensional Voronoĭ tilings
Authors: Balister Paul , Bollobás Béla 
Published: November 2009

AbstractLet $\cal{P}$ be the set of points in a realization of a uniform Poisson process in ℝn. The set $\cal{P}$ determines a Voronoĭ tiling of ℝn. Construct an infinite graph $\cal{G}$ with vertex set $\cal{P}$ and edges joining vertices when the corresponding Voronoĭ cells share a (n − 1)‐dimensional boundary face. We consider bond percolation models on $\cal{G}$ obtained by declaring each edge xy of $\cal{G}$ open independently with probability p(∥x − y∥), depending only on the Euclidean distance ∥x − y∥ between the vertices. We give some sufficient conditions on p(t) that ensures that an infinite connected component (i.e., percolation) occurs, or does not occur. In particular, we show that for p(t) = p is a constant, there is a phase transition at a critical probability p = pc(n), where 2−n(5nlog n)−1 ≤ pc(n) ≤ C2−n $\sqrt{n}\;{\rm log} \; n$. We also show that if p(t) = e−λt then there is a phase transition at a critical parameter λ = λc(n), where λc(n) = (log e2 + o(1))n/2rn, where rn is the radius of the n‐dimensional sphere that, on average, contains a single point of $\cal{P}$. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Coloring H‐free hypergraphs
Authors: Bohman Tom , Frieze Alan , Mubayi Dhruv 
Published: November 2009

AbstractFix r ≥ 2 and a collection of r‐uniform hypergraphs $\cal{H}$. What is the minimum number of edges in an $\cal{H}$‐free r‐uniform hypergraph with chromatic number greater than k? We investigate this question for various $\cal{H}$. Our results include the following:

An (r,l)‐system is an r‐uniform hypergraph with every two edges sharing at most l vertices. For k sufficiently large, there is an (r,l)‐system with chromatic number greater than k and number of edges at most c(kr−1 log k)l/(l−1), where

This improves on the previous best bounds of Kostochka et al. (Random Structures Algorithms 19 (2001), 87–98). The upper bound is sharp apart from the constant c as shown in (Random Structures Algorithms 19 (2001) 87–98).

The minimum number of edges in an r‐uniform hypergraph with independent neighborhoods and chromatic number greater than k is of order kr+1/(r−1) log O(1)k as k → ∞. This generalizes (aside from logarithmic factors) a result of Gimbel and Thomassen (Discrete Mathematics 219 (2000), 275–277) for triangle‐free graphs.

Let T be an r‐uniform hypertree of t edges. Then every T‐free r‐uniform hypergraph has chromatic number at most 2(r − 1)(t − 1) + 1. This generalizes the well‐known fact that every T‐free graph has chromatic number at most t.

Several open problems and conjectures are also posed. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Exemplary data set sample size calculation for Wilcoxon–Mann–Whitney tests
Authors: Divine George , Kapke Alissa , Havstad Suzanne , Joseph Christine L. M. 
Published: November 2009

AbstractZhao, Rahardja and Qu consider sample size calculation for Wilcoxon–Mann–Whitney (WMW) tests for data with ties, and present a straightforward formula. We observe that the ‘exemplary data set’ approach, usually applied in more complex situations, has a close relationship to the Zhao–Rahardja–Qu method for WMW sample size estimation and they are asymptotically equivalent. Therefore, the exemplary data set approach can be used to easily obtain estimates similar to those that the closed formula gives. We illustrate application of both methods for a WMW sample size estimation example, and also extend the simulation study presented by Zhao et al. We find that the Zhao–Rahardja–Qu formula (and by extension the exemplary data set method) can give estimates just as accurate as those obtained using either the Kolassa approach (via nQuery Advisor) or the O'Brien–Castelloe approach (via SAS 9.2 PROC POWER), for 1:1 and 1:2 allocation ratios. However, the latter two methods can be more accurate for a ratio of 1:4 or 1:19. Finally, we note the general utility of the exemplary data set approach for sample size estimation, even in other situations where closed‐form sample size formulae exist. Copyright © 2009 John Wiley & Sons, Ltd.
An FGF4-FRS2α-Cdx2 Axis in Trophoblast Stem Cells Induces Bmp4 to Regulate Proper Growth of Early Mouse Embryos
Authors: Murohashi Michiko , Nakamura Takahisa , Tanaka Satoshi , Ichise Taeko , Yoshida Nobuaki , Yamamoto Tadashi , Shibuya Masabumi , Schlessinger Joseph , Gotoh Noriko 
Published: November 2009

Abstract
A variety of stem cells are controlled by the actions of multiple growth factors in vitro. However, it remains largely unclear how growth factors control the proliferation and differentiation of stem cells in vivo. Here, we describe a novel paracrine mechanism for regulating a stem cell niche in early mammalian embryos, which involves communication between the inner cell mass (ICM) and the trophectoderm, from which embryonic stem (ES) cells and trophoblast stem (TS) cells can be derived, respectively. It is known that ES cells produce fibroblast growth factor (FGF)4 and that TS cells produce bone morphogenetic protein (Bmp)4. We provide evidence that FRS2α mediates activation of the extracellular signal-regulated progein kinase (ERK) pathway to enhance expression of transcription factor Cdx2 in TS cells in response to FGF4. Cdx2 in turn binds to an FGF4-responsive enhancer element of the promoter region of Bmp4, leading to production and secretion of Bmp4. Moreover, exogenous Bmp4 is able to rescue the defective growth of Frs2α-null ICM. These findings suggest an important role of Cdx2 for production of Bmp4 in TS cells to promote the proper growth of early mouse embryos.