bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instrument dependence of electrospray ionization and tandem mass spectrometric fragmentation of the gingerols
Authors: Jiang Hongliang , Somogyi Árpád , Timmermann Barbara N. , Gang David R. 
Published: September 2006

AbstractThe gingerols, including [6]‐, [8]‐, and [10]‐gingerols, a series of chemical homologs differentiated by the length of their unbranched alkyl chains, have been identified as major active components in fresh ginger rhizome. The purpose of this study was to investigate the utility of ion trap liquid chromatography/tandem mass spectrometry (LC/MS/MS) as an online tool to identify and quantify these compounds in raw or processed ginger rhizome samples. Negative mode electrospray ionization (ESI) was used in MS, MS/MS and MSn experiments in quadrupole ion trap instruments from two different manufacturers and in high‐resolution and accurate mass MS and MS/MS experiments in a Fourier transform ion cyclotron resonance mass spectrometer to elucidate the ionization and fragmentation mechanisms of these compounds in these instruments. Positive mode ESI, which generated many more fragment ions in full scan MS even under gentle ionization conditions, was also used in LC/MS and MS/MS experiments and in direct infusion MS and MS/MS experiments. Consistent and predictable ionization and fragmentation behaviors were observed for all gingerols when analyzed in the same instrument. Instruments from different manufacturers, however, had different ionization mechanisms. The major difference between instruments was their ability to form covalent dimer adducts of the gingerols. Subsequent fragmentation patterns of the precursor ions were essentially identical. These results clearly demonstrate that LC/MS instruments produce data that cannot necessarily be replicated in other laboratories, especially if those laboratories do not have the same instrument model from the same manufacturer. This presents major problems for metabolite target analysis, metabolic profiling and metabolomics investigations, which would benefit from LC/MS mass spectrum libraries as they do from GC/MS mass spectrum libraries, because such libraries may not be valid across platforms. Copyright © 2006 John Wiley & Sons, Ltd.
Sharp thresholds and percolation in the plane
Authors: Bollobás Béla , Riordan Oliver 
Published: September 2006

AbstractRecently, it was shown by Bollobás and Riordan Probab Theory Related Fields 136 (2006), 417–468 that the critical probability for random Voronoi percolation in the plane is 1/2. As a by‐product of the method, a short proof of the Harris–Kesten Theorem was given by Bollobás and Riordan Bull London Math Soc 38 (2006), 470–484. The aim of this paper is to show that the techniques used in these papers can be applied to many other planar percolation models, both to obtain short proofs of known results and to prove new ones. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
What is stopping sustainable building in England? Barriers experienced by stakeholders in delivering sustainable developments
Authors: Williams Katie , Dair Carol 
Published: September 2006

AbstractIn England there is both top‐down and bottom‐up pressure to deliver a sustainable built environment. However, most new projects display few sustainability features. This paper presents 12 barriers to achieving sustainability in development schemes, drawn from qualitative research on five recently completed projects in England. The barriers that were identified by the stakeholders in the schemes include a lack of consideration of sustainability measures, real and perceived costs and inadequate expertise and powers. The paper concludes by suggesting some ways in which these barriers might be overcome. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Structure dependent packing behavior of phthalocyanine on the surface of graphite
Authors: Liu Ai‐Zhen , Lei Sheng‐Bin 
Published: September 2006

AbstractThe surface‐assembly behavior of phthalocyanine is of great importance because of the molecule's important application as an organic semiconductor in electronics and in solar cells. In this work, the surface‐assembly behavior on graphite of four metal phthalocyanines bearing different substituents was investigated by scanning tunneling microscopy. Owing to the difference in the substituents, the packing symmetries of these phthalocyanines are apparently different. The results point out that the packing mode of phthalocyanine is not only influenced by molecular symmetry but also by steric hindrance. Copyright © 2006 John Wiley & Sons, Ltd.
Studies of protection of iron corrosion by rosin imidazoline self‐assembled monolayers
Authors: Liu Xiuyu , Chen Shenhao , Tian Fang , Ma Houyi , Shen Lixia , Zhai Hongyan 
Published: September 2006

AbstractA type of rosin imidazoline (IM) has been synthesized using rosin acid and diethylenetriamine (DETA) as raw materials. The monolayers of IM were assembled on the surface of iron. The monolayers of the IM inhibitor were characterized by electrochemical impedance spectroscopy (EIS), electrochemical polarization curves and double‐layer capacitance. Surface analysis was carried out to establish the mechanism of corrosion inhibition of iron by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy. The IM inhibitor showed good inhibition efficiency for iron in 0.1 M H2SO4. The inhibition mechanism of IM inhibitor was interpreted using molecular simulation. Copyright © 2006 John Wiley & Sons, Ltd.
A simulation study comparing properties of heterogeneity measures in meta‐analyses
Authors: Mittlböck M. , Heinzl H. 
Published: September 2006

AbstractThe assessment of heterogeneity or between‐study variance is an important issue in meta‐analysis. It determines the statistical methods to be used and the interpretation of the results. Tests of heterogeneity may be misleading either due to low power for sparse data or to the detection of irrelevant amounts of heterogeneity when many studies are involved. In the former case, notable heterogeneity may remain unconsidered and an unsuitable model may be chosen and the latter case may lead to unnecessary complex analyses strategies. Measures of heterogeneity are better suited to determine appropriate analyses strategies. We review two measures with different scaling and compare them with the heterogeneity test. Estimates of the within‐study variance are discussed and a new total information measure is introduced. Various properties of the quantities in question are assessed by a simulation study.Heterogeneity test and measures are not directly related to the amount of between‐study variance but to the relative increase of variance due to heterogeneity. It is more favourable to base the within‐study variance estimate on the squared weights of individual studies than on the sum of weights. A heterogeneity measure scaled to a fixed interval needs reference values for proper interpretation. A measure defined by the relation of between‐ to within‐study variance has a more natural interpretation but no upper limit. Both measures are quantifications of the impact of heterogeneity on the meta‐analysis result as both depend on the variance of the individual study effects and thus on the number of patients in the studies. Copyright © 2006 John Wiley & Sons, Ltd.
A comparison of three different models for estimating relative risk in meta‐analysis of clinical trials under unobserved heterogeneity
Authors: Kuhnert Ronny , Böhning Dankmar 
Published: September 2006

AbstractWe focus on the comparison of three statistical models used to estimate the treatment effect in meta‐analysis when individually pooled data are available. The models are two conventional models, namely a multi‐level and a model based upon an approximate likelihood, and a newly developed model, the profile likelihood model which might be viewed as an extension of the Mantel–Haenszel approach. To exemplify these methods, we use results from a meta‐analysis of 22 trials to prevent respiratory tract infections. We show that by using the multi‐level approach, in the case of baseline heterogeneity, the number of clusters or components is considerably over‐estimated. The approximate and profile likelihood method showed nearly the same pattern for the treatment effect distribution. To provide more evidence two simulation studies are accomplished. The profile likelihood can be considered as a clear alternative to the approximate likelihood model. In the case of strong baseline heterogeneity, the profile likelihood method shows superior behaviour when compared with the multi‐level model. Copyright © 2006 John Wiley & Sons, Ltd.
Indirectly predicting the maintenance effort of open‐source software
Authors: Yu Liguo 
Published: September 2006

AbstractAn accurate maintenance effort model is essential for a successful software maintenance process. Maintenance effort is usually measured in person‐hours used to perform a maintenance task. However, maintenance effort data are usually only available for strictly managed software, such as closed‐source software. In other software projects that do not have complete maintenance records, especially some open‐source software, there are no direct data for maintenance effort, which precludes the establishment of a maintenance effort model. In this paper, we report a series of studies aimed at presenting a method for indirectly predicting the maintenance effort of open‐source software. This report covers two parts of our research. First, we examine the maintenance data from NASA SEL closed‐source software projects and identify some software measures that can be used to indirectly represent maintenance effort. Second, based on the findings in the first part, we analyze 121 recent versions of Linux, and use linear regression to construct two indirect maintenance effort models for the Linux project. Our study demonstrates the applicability of this approach to indirectly predicting the maintenance effort and improving the software maintenance process. Copyright © 2006 John Wiley & Sons, Ltd.
Supercritical elliptic problems in domains with small holes
Authors: del Pino Manuel , Wei Juncheng 
Published: September 2006

Let

\mathcal D

be a bounded, smooth domain in

\mathbb{R}^{N}

,

N⩾3

,

P\in \mathcal D

. We consider the boundary value problem in

\Omega = \mathcal D \setminus B_{\delta }(P)

,

\mathrm{\Delta }u + u^{p} = 0,\:u > 0\:\text{in }\Omega ,\:u = 0\:\text{on }\partial \Omega ,

with

p

supercritical, namely

p > \frac{N + 2}{N−2}

. We find a sequence

p_{1} < p_{2} < p_{3} < \cdots,\:\text{with }\lim\limits_{k\rightarrow + \infty }p_{k} = + \infty ,

such that if

p

is given, with

p \neq p_{j}

for all

j

, then for all

\delta > 0

sufficiently small, this problem is solvable.

Résumé

Soient

\mathcal D

un domaine borné régulier de

\mathbb{R}^{N}

,

N⩾3

, et

P\in \mathcal D

. Nous définissons

\Omega = \mathcal D \setminus B_{\delta }(P)

et nous nous intéressons au problème de Dirichlet

\mathrm{\Delta }u + u^{p} = 0,\:u > 0\:\text{dans }\Omega ,\:u = 0\:\text{sur }\partial \Omega ,

dans le cas où l'exposant

p

est surcritique, c'est à dire que

p > \frac{N + 2}{N−2}

. Nous démontrons l'existence d'une suite d'exposants

p_{1} < p_{2} < p_{3} < ⋯

qui tend vers l'infini et telle que, si

p

est fixé,

p \neq p_{j}

pour tout

j

, il existe

\delta _{p} > 0

assez petit pour lequel le problème ci-dessus admet une solution pour tout

\delta ⩽\delta _{p}

.
Periodic solutions of second order Hamiltonian systems bifurcating from infinity
Authors: Fura Justyna , Rybicki Sławomir 
Published: September 2006

The goal of this article is to study closed connected sets of periodic solutions, of autonomous second order Hamiltonian systems, emanating from infinity. The main idea is to apply the degree for

\mathrm{SO}(2)

-equivariant gradient operators defined by the second author in [S. Rybicki,

\mathrm{SO}(2)

-degree for orthogonal maps and its applications to bifurcation theory, Nonlinear Anal. TMA 23 (1) (1994) 83–102]. Using the results due to Rabier [P. Rabier, Symmetries, topological degree and a theorem of Z.Q. Wang, Rocky Mountain J. Math. 24 (3) (1994) 1087–1115] we show that we cannot apply the Leray–Schauder degree to prove the main results of this article. It is worth pointing out that since we study connected sets of solutions, we also cannot use the Conley index technique and the Morse theory.

Résumé

Le but de cet article est l'étude des ensembles fermés et connexes de solutions périodiques, émanant de l'infini, des systèmes hamiltoniens autonomes de second ordre. L'idée principale consiste à appliquer le degré aux opérateurs de gradient

\mathrm{SO}(2)

-équivariants définis par le second auteur dans [S. Rybicki,

\mathrm{SO}(2)

-degree for orthogonal maps and its applications to bifurcation theory, Nonlinear Anal. TMA 23 (1) (1994) 83–102]. Moyennant un résultat de Rabier [P. Rabier, Symmetries, topological degree and a theorem of Z.Q. Wang, Rocky Mountain J. Math. 24 (3) (1994) 1087–1115], on démontre que l'on ne peut pas appliquer le degré de Leray–Schauder pour obtenir le résultat principal de ce travail. Il est important de souligner que, vu que l'on étudie des ensembles connexes de solutions, ni la technique de l'indice de Conley, ni la théorie de Morse ne peuvent être appliquées ici.
Exact controllability in projections for three-dimensional Navier–Stokes equations
Authors: Shirikyan Armen 
Published: September 2006

The paper is devoted to studying controllability properties for 3D Navier–Stokes equations in a bounded domain. We establish a sufficient condition under which the problem in question is exactly controllable in any finite-dimensional projection. Our sufficient condition is verified for any torus in

\mathbb{R}^{3}

. The proofs are based on a development of a general approach introduced by Agrachev and Sarychev in the 2D case. As a simple consequence of the result on controllability, we show that the Cauchy problem for the 3D Navier–Stokes system has a unique strong solution for any initial function and a large class of external forces.

Résumé

L'article est consacré à l'étude de propriétés de contrôlabilité pour les équations de Navier–Stokes 3D dans un domaine borné. On établit une condition suffisante sous laquelle le problème en question est exactement contrôlable en toute projection de dimension finie. Notre condition suffisante est vérifiée pour tout tore dans

\mathbb{R}^{3}

. Les démonstrations sont basées sur un développement d'une approche générale introduite par Agrachev and Sarychev dans le cas 2D. Comme une conséquence simple du résultat de contrôlabilité, on montre que le problème de Cauchy pour le système de Navier–Stokes 3D possède une unique solution forte pour toute donnée initiale et une grande classe de forces extérieures.
Climate Forcing Due to the 8200 Cal yr BP Event Observed at Early Neolithic Sites in the Eastern Mediterranean
Authors: Weninger Bernhard , Alram-Stern Eva , Bauer Eva , Clare Lee , Danzeglocke Uwe , Jöris Olaf , Kubatzki Claudia , Rollefson Gary , Todorova Henrieta , van Andel Tjeerd 
Published: September 2006

AbstractWe explore the hypothesis that the abrupt drainage of Laurentide lakes and associated rapid switch of the North Atlantic thermohaline circulation 8200 yr ago had a catastrophic influence on Neolithic civilisation in large parts of southeastern Europe, Anatolia, Cyprus, and the Near East. The event at 8200 cal yr BP is observed in a large number of high-resolution climate proxies in the Northern Hemisphere, and in many cases corresponds to markedly cold and arid conditions. We identify the relevant archaeological levels of major Neolithic settlements in Central Anatolia, Cyprus, Greece and Bulgaria, and examine published stratigraphic, architectural, cultural and geoarchaeological studies for these sites. The specific archaeological events and processes we observe at a number of these sites during the study interval 8400–8000 cal yr BP lead us to refine some previously established Neolithisation models. The introduction of farming to South-East Europe occurs in all study regions (Thrace, Macedonia, Thessaly, Bulgaria) near 8200 cal yr BP. We observe major disruptions of Neolithic cultures in the Levant, North Syria, South-East Anatolia, Central Anatolia and Cyprus, at the same time. We conclude that the 8200 cal yr BP aridity event triggered the spread of early farmers, by different routes, out of West Asia and the Near East into Greece and Bulgaria.
Genetic inactivation of prohormone convertase (PC1) causes a reduction in cholecystokinin (CCK) levels in the hippocampus, amygdala, pons and medulla in mouse brain that correlates with the degree of colocalization of PC1 and CCK mRNA in these structures in rat brain
Authors: Cain B. M. , Connolly K. , Blum A. C. , Vishnuvardhan D. , Marchand J. E. , Zhu X. , Steiner D. F. , Beinfeld M. C. 
Published: September 2006

AbstractProhormone convertase (PC1) is found in endocrine cell lines that express cholecystokinin (CCK) mRNA and process pro CCK to biologically active products. Other studies have demonstrated that PC1 may be a one of the enzymes responsible for the endoproteolytic cleavages that occur in pro CCK during its biosynthesis and processing. Prohormone convertase 1 (PC1) has a distribution that is similar to cholecystokinin (CCK) in rat brain. A moderate to high percentage of CCK mRNA‐positive neurons express PC1 mRNA. CCK levels were measured in PC1 knockout and control mice to assess the degree to which loss of PC1 changed CCK content. CCK levels were decreased 62% in hippocampus, 53% in amygdala and 57% in pons‐medulla in PC1 knockout mice as compared to controls. These results are highly correlated with the colocalization of CCK and PC1. The majority of CCK mRNA‐positive neurons in the pyramidal cell layer of the hippocampus express PC1 mRNA and greater than 50% of CCK mRNA‐positive neurons in several nuclei of the amygdala also express PC1. These results demonstrate that PC1 is important for CCK processing. PC2 and PC5 are also widely colocalized with CCK. It may be that PC2, PC5 or another non‐PC enzyme are able to substitute for PC1 and sustain production of some amidated CCK. Together these enzymes may represent a redundant system to insure the production of CCK.
Activation of calpain‐1 in myelin and microglia in the white matter of the aged rhesus monkey
Authors: Hinman Jason D. , Duce James A. , Siman Robert A. , Hollander William , Abraham Carmela R. 
Published: September 2006

AbstractUltrastructural disruption of myelin sheaths and a loss of myelin with age are well‐documented phenomena in both the human and rhesus monkey. Age‐dependent activation of calpain‐1 (EC 3.4.22.52) has been suggested as a plausible mechanism for increased proteolysis in the white matter of the rhesus monkey. The present study documents activation of calpain‐1 throughout brain white matter in aged animals, evidenced by immunodetection of the activated enzyme as well as a calpain‐derived spectrin fragment in both tissue section and Triton X‐100‐soluble homogenate of subcortical white matter from the frontal, temporal, and parietal lobes. Separation of myelin fractions from brain stem tissue into intact and floating myelin confirmed previous reports of an age‐related increase in activated calpain‐1 in the floating fraction. Measurements of calpain‐1 activity using a fluorescent substrate revealed an age‐related increase in calpain‐1 proteolytic activity in the floating myelin fraction consistent with immunodetection of the activated enzyme in this fraction. Double‐immunofluorescence demonstrated co‐localization of activated calpain‐1 with human leukocyte antigen‐DR (HLA‐DR), a marker for activated microglia, suggesting that these cells represent the major source of the increase in activated calpain‐1 in the aging brain. These data solidify the role of calpain‐1 in myelin protein metabolism and further implicate activated microglia in the pathology of the aging brain.
Microvascular Display of Xanthine Oxidase and NADPH Oxidase in the Spontaneously Hypertensive Rat
Authors: DELANO FRANK A. , PARKS DALE A. , RUEDI JULIE M. , BABIOR BERNARD M. , SCHMID‐SCHÖNBEIN GEERT W. 
Published: September 2006

ABSTRACTObjective: Oxygen free radical production in hypertension may be associated with elevated arteriolar tone and organ injury. Previous results suggest an enhanced level of oxygen free radical formation in microvascular endothelium and in circulating neutrophils associated with xanthine oxidase activity in the spontaneously hypertensive rats (SHR) compared with their normotensive controls, the Wistar Kyoto rats (WKY). The aim of this study was to gain more detailed understanding of where oxidative enzymes are located in the microcirculation.Methods: An approach was developed to delineate the cellular distribution of two selected oxidative enzymes, xanthine oxidase and nicotinamide adenine dinucleotide phosphate (NADPH) dependent oxidase (protein 67‐kDa fraction). Immunolabeling with peroxidase substrate was utilized, which permits full delineation of the primary antibody in all microvascular structures of the mesentery.Results: Xanthine oxidase is present in the endothelium of all segments of the microcirculation, in mast cells, and in parenchymal cells of the mesentery. NADPH oxidase can be detected in the endothelium, leukocytes, and mast cells and with lower levels in parenchymal cells. The mesentery of WKY and SHR has similar enzyme distributions with enhancements on the arteriolar and venular side of the microcirculation that coincide with the sites of enhanced free radical production recently reported. Immune label measurements under standardized conditions indicate that both enzymes are significantly enhanced in the SHR. Adrenalectomy, which serves to reduce the blood pressure and free radical production of the SHR to normotensive levels, leads to a reduction of NADPH and xanthine oxidase to normotensive levels, while supplementation of adrenalectomized SHR with dexamethasone significantly increases the oxidase expression in several parts of the microcirculation to levels above the WKY rats.Conclusion: The results indicate that enhanced expression of NADPH and xanthine oxidase in the SHR depends on an adrenal pathway that is detectable in the arteriolar and venular network at high and low pressure regions of the circulation.
Inhibition of NAD(P)H Oxidase Alleviates Impaired NOS‐dependent Responses of Pial Arterioles in Type 1 Diabetes Mellitus
Authors: MAYHAN WILLIAM G. , ARRICK DENISE M. , SHARPE GLENDA M. , PATEL KAUSHIK P. , SUN HONG 
Published: September 2006

ABSTRACTObjective: The goal was to identify the role of NAD(P)H oxidase in cerebrovascular dysfunction in type 1 diabetes mellitus (T1D).Methods: In a first series of studies, rats were assigned to nondiabetic, diabetic (streptozotocin; 50 mg/kg IP), nondiabetic‐apocynin (40 mg/kg/day in drinking water)‐treated and diabetic‐apocynin‐treated groups. Two to three months later, the authors examined in vivo responses of pial arterioles to nitric oxide synthase (NOS)‐dependent (acetylcholine and adenosine diphosphate (ADP)) and ‐independent (nitroglycerin) agonists. Next, they used Western blot analysis to examine protein levels for subunits of NAD(P)H oxidase in cerebral microvessels and parietal cortex tissue of nondiabetic and diabetic rats. Finally, they measured superoxide production by parietal cortex tissue in nondiabetic and diabetic rats.Results: Acetylcholine‐ and ADP‐induced dilatation of pial arterioles was impaired in diabetic compared to nondiabetic rats. In addition, while apocynin did not alter responses in nondiabetic rats, apocynin alleviated T1D‐induced impairment of NOS‐dependent vasodilatation. In addition, p47phox and gp91phox proteins were elevated in cerebral microvessels and parietal cortex tissue, respectively, of diabetic compared to nondiabetic rats. Further, basal production of superoxide was increased in diabetic compared to nondiabetic rats and apocynin decreased this basal production.Conclusions: The findings suggest that T1D impairs NOS‐dependent reactivity of cerebral arterioles by a mechanism related to the formation of superoxide via activation of NAD(P)H oxidase.