bluuebunny/crossref_metadata_2025_split huggingface dataset:
X‐ray absorption and luminescence properties of metallic copper nanoparticles embedded in a glass matrix
Authors: Roqué J. , Poolton N. R. J. , Molera J. , Smith A. D. , Pantos E. , Vendrell‐Saz M. 
Published: March 2006

AbstractA new method of ion‐exchange between raw compounds containing copper oxide and alkali glasses has been used to grow copper nanoparticles within a glass matrix, forming a metal–glass nanocomposite that is the structure on which both ancient and modern lustre glazes are based. When excited by X‐rays at 300 K, two dominant emission bands appear in the material in the visible region, peaking at 2.60 eV and 1.98 eV. Synchrotron radiation methods are deployed that enables the luminescence and structural properties of the nanocomposite to be interlinked. Standard Extended X‐ray Absorption Fine Structure (EXAFS) shows that both metallic copper and copper oxide local sites structure are present in the glass matrix, and the detailed atomic arrangement of each are derived; however, the method provides no information as to whether either structures are actually involved in the luminescence processes. In order to provide this direct link, Optically Detected X‐ray Absorption Spectroscopy (OD‐XAS) has been deployed, and this provides strong evidence that copper metal nanoparticles are responsible for the red emission. The method also shows that the X‐ray absorption processes of the metal particles and silicate lattice (that result in the red and blue emissions respectively) are distinctly different. This is the first report of OD‐XAS involving metallic nanoparticles, and opens the possibility of using the method more generally for metal nanoparticle research. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ONETEP: linear‐scaling density‐functional theory with local orbitals and plane waves
Authors: Haynes Peter D. , Skylaris Chris‐Kriton , Mostofi Arash A. , Payne Mike C. 
Published: March 2006

AbstractAn overview of the ONETEP (Order‐N Electronic Total Energy Package) code is presented, focusing on the twin aims of overall linear scaling and controlled accuracy. The method is outlined, including a description of the density‐matrix formulation of density‐functional theory, and the optimisation procedures for both the density‐kernel and the local orbitals or non‐orthogonal generalised Wannier functions. Results of applying the method to a variety of systems are presented to demonstrate the accomplishment of the original aims. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Population inversion, temperature, and photon distributions of the generalized fermionic Ising ferromagnetic model: Path‐integral representation of the spin system
Authors: Grinberg Horacio 
Published: March 2006

AbstractThe quantum partition function and the emerging energy of a fermionic Ising ferromagnetic model involving all possible interactions (generalized Ising model) are obtained from an appropriate tracing of the analytic propagator path integral over Grassmann variable coherent nonorthogonal states in the imaginary time domain. The dynamics derived from the interaction of this system with a single‐mode cavity field in the rotating wave approximation is investigated for nonresonant states within the framework of the Jaynes–Cummings two‐level model consisting of the vacuum state and a thermally averaged manifold of excited states. Time evolution of the population inversion is computed in the nanosecond time scale, assuming that the initial coherent state of the field is given by a Poisson distribution. The limit of high temperatures characterizing the manifold of excited states becomes chaotic with rapid oscillations, whereas the ground state is described correctly in the thermodynamic limit by the vacuum state. A breakup is seen in the photon distribution into a series of peaks because of the detuning between the spin system and the field. However, this structure is smeared out, and the general shape is preserved in the computation emerging from the Laplace transform of the photon distribution. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Conjugated chemical trees with minimal energy and prescribed diameter
Authors: Ou Jianping 
Published: March 2006

AbstractThe energy of a molecular graph G is defined as the sum of the absolute values of the eigenvalues of A(G), where A(G) is the adjacency matrix of this graph. This article characterizes conjugated chemical trees with prescribed diameter and minimal energies and presents explicit expressions of their Hosoya indices. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Severe acute respiratory syndrome (SARS) coronavirus: application of monoclonal antibodies and development of an effective vaccine
Authors: Tsunetsugu‐Yokota Yasuko , Ohnishi Kazuo , Takemori Toshitada 
Published: March 2006

AbstractSARS‐CoV is a new type of human coronavirus identified as a causative agent of severe acute respiratory syndrome (SARS). On the occasion of the SARS outbreak, various monoclonal antibodies (mAbs) against SARS‐CoV have been developed and applied for diagnosis, clinical management and basic research. In this review, we overview the biochemical and functional properties and applications of these SARS‐CoV mAbs. We also focus on a variety of vaccines currently under development and discuss the immune response elicited by these vaccines in animal models, hopefully to better understand what we need to do next to fight against newly emerging pathogens in the future. Copyright © 2006 John Wiley & Sons, Ltd.
Gain‐scheduled H∞ filtering of parameter‐varying systems
Authors: Zhou Shaosheng , Zhang Baoyong , Xing Zheng Wei 
Published: March 2006

AbstractThis paper deals with the gain‐scheduled H∞ filtering problem for a class of parameter‐varying systems. A sufficient condition for the existence of a gain‐scheduled filter, which guarantees the asymptotic stability with an H∞ noise attenuation level bound for the filtering error system, is given in terms of a finite number of linear matrix inequalities (LMIs). The filter is designed to be parameter‐varying and have a nonlinear fractional transformation structure. A numerical example is presented to demonstrate the application of the proposed method. Copyright © 2006 John Wiley & Sons, Ltd.
Energizing the island community: a review of policy standpoints for energy in small island states and territories
Authors: Stuart E. Kathy 
Published: March 2006

AbstractSmall island states and island territories of larger countries tend to have ample renewable energy potential from sun, wind, waves, biomass and other sources. Nevertheless, they rely heavily on fossil fuels to generate electricity. Fluctuations in fossil fuel prices may impact significantly upon small island economies. This paper aims to help researchers and decision‐makers better understand the unique features of small islands in relation to the power industry. The paper identifies public policy influencing production of electricity and limitations to energy policy reform in small islands. A range of conventional and renewable energy options available to small island policy‐makers is presented using anecdotal evidence. It is argued that small islands need to build upon their energy resource potentials and by this exert more control over their energy futures. The paper concludes by recommending holistic strategies that small islands can use to enhance their long‐term energy security and sustainability. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Teaching nature of science explicitly in a first‐grade internship setting
Authors: Akerson Valarie L. , Volrich Morgan L. 
Published: March 2006

AbstractThis case study focused on a preservice teachers' (Morgan) efforts to explicitly emphasize nature of science (NOS) elements in her first‐grade internship classroom. The study assessed the change in first grade students' views of the inferential, tentative, and creative NOS as a result of the explicit instruction. Morgan held appropriate views of NOS, had the intention and motivation to teach NOS, and had a supporting experience explicitly emphasizing NOS embedded in physics content to peer college students. Data sources included weekly classroom observations of explicit NOS science lessons taught by Morgan, interview of Morgan to determine that her views of NOS were informed and that she would have the NOS content knowledge to teach in line with recommended reforms, and interviews of the first‐grade students pre‐ and postinstruction to determine the influence of Morgan's instruction on their views of observation and inference, the tentative NOS, and the creative and imaginative NOS. Data were analyzed to determine (a) the approaches Morgan used to emphasize NOS in her instruction, and (b) students' views of NOS pre‐ and postinstruction to track change in their views. It was found that Morgan was able to explicitly emphasize NOS using three teacher‐designed methods, and that the influence on student views of the inferential, tentative, and creative NOS was positive. Implications for teacher development are provided. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 377–394, 2006
Adenylyl cyclase signaling mechanisms of relaxin and insulin action: Similarities and differences
Authors: Pertseva Marianna , Shpakov Alexander , Kuznetsova Ludmila , Plesneva Svetlana , Omeljaniuk Evgeniya 
Published: March 2006

AbstractThe adenylyl cyclase signaling mechanism (ACSM) of relaxin H2 action was discovered and deciphered in mammalian muscles. A study of signaling blocks involved in ACSM of relaxin in comparison with that of insulin previously detected showed a close similarity throughout the post‐receptor signaling chain of both hormones. The inhibitory action of tyrosine kinase blockers on the hormone AC activating effect indicates that the relaxin receptor involved in ACSM is likely to be of the tyrosine kinase type. However, a recent discovery of a relaxin receptor with serpentine architecture leaves open the question concerning the existence of receptor of the tyrosine kinase type. The structural‐functional organization of the ACSM due to the action of relaxin—shown here for the first time—can be presented as the following signaling sequence: relaxin receptor ⇒ Gi protein (βγ‐dimer) ⇒ phosphatidylinositol 3‐kinase ⇒ protein kinase Cζ ⇒ Gs protein ⇒ adenylyl cyclase. According to our hypothesis, the regulatory action of the insulin superfamily peptides on cell processes (proliferation, apoptosis, and metabolism) is mediated via ACSM.
Stabilization of hypoxia inducible factor rather than modulation of collagen metabolism improves cardiac function after acute myocardial infarction in rats
Authors: Philipp Sebastian , Jürgensen Jan Steffen , Fielitz Jens , Bernhardt Wanja M. , Weidemann Alexander , Schiche Astrid , Pilz Bernhard , Dietz Rainer , Regitz‐Zagrosek Vera , Eckardt Kai‐Uwe , Willenbrock Roland 
Published: March 2006

AbstractProlyl hydroxylase domain‐containing enzymes (PHD) hydroxylate a proline residue that controls the degradation of hypoxia inducible factor (HIF). Hypoxia inhibits this hydroxylation thus increasing HIF levels. HIF is upregulated in ischemic tissues, growing tumors and in nonischemic, mechanically stressed myocardium. Pharmacological inhibition of prolyl 4‐hydroxylase (P4‐H) stabilizes HIF‐protein in vitro and may modulate collagen turnover. The aims of this study were to investigate whether inhibition of P4‐H protects myocardium against ischemia, and whether the observed effects are related to modulation of collagen metabolism or due to the stabilization of HIF.Methods:Rats were treated with a specific P4‐H inhibitor (P4‐HI) or vehicle starting 2 days before induction of myocardial infarction (MI). Rats were investigated 7 or 30 days after MI. Induction of HIF‐1α and −2α was visualized by immunohistochemistry. Expression of growth factors (connective tissue growth factor, Osteopontin) and mRNA expression and protein levels of Collagen I and III as well as HIF‐2α were measured.Results:P4‐HI augments HIF in the myocardium as early as 24 h after treatment. P4‐HI did not alter the MI‐induced enhanced expression of growth factors and collagen. Treatment with P4‐HI significantly reduced heart and lung weight, improved left ventricular contractility, prevented left ventricular enlargement and improved left ventricular ejection fraction without affecting infarct size after 30 days.Conclusions:Specific inhibition of the P4‐H improved cardiac function without affecting the infarct size after experimental myocardial infarction in rats. Stabilization of HIF rather than inhibition of collagen maturation by P4‐HI may prevent cardiac remodeling after MI.
Influence of cardiac‐resynchronization therapy on heart rate and blood pressure variability: 1‐year follow‐up
Authors: Piccirillo Gianfranco , Magrí Damiano , di Carlo Silvia , De Laurentis Tiziana , Torrini Alessia , Matera Sabrina , Magnanti Marzia , Bernardi Leda , Barillà Franco , Quaglione Raffaele , Ettorre Evaristo , Marigliano Vincenzo 
Published: March 2006

AbstractBackground:Several studies have shown that cardiac‐resynchronization therapy (CRT) improves haemodynamic function, cardiac symptoms, and heart rate variability (HRV) and reduces the risk of mortality and sudden death in subjects with chronic heart failure (CHF). In subjects with CHF, power spectral values for the low‐frequency (LF) component of RR variability ≥13 ms2, are associated with an increased risk of sudden death.Aims and methods:To assess whether spectral indexes obtained by power spectral analysis of HRV and systolic blood pressure (SBP) variability could predict malignant ventricular arrhythmias in patients with severe CHF treated with an implantable cardioverter–defibrillator (ICD) alone or with ICD+CRT. In addition, changes in non‐invasive spectral indices using short‐term power spectral analysis of HRV and SBP variability during controlled breathing in 15 patients with CHF treated with an ICD alone and 16 patients receiving ICD+CRT, were assessed pre‐treatment and at 1 year.Results:Arrhythmias necessitating an appropriate ICD shock were more frequent in subjects who had low LF power. CRT improved all spectral components, including LF power.Conclusions:Low LF power values predict an increased risk of malignant ventricular arrhythmias; after 1 year of CRT most non‐spectral and spectral data, including LF power, improved. Whether these improvements lead to better long‐term survival in patients with CHF remains unclear.
Holocene environmental change and vegetation contraction in the Sonoran Desert
Authors: McAuliffe Joseph R. , McDonald Eric V. 
Published: March 2006

AbstractTwo types of microtopographic features (plant scar mounds and plant scar depressions) on surfaces of barren desert pavements provide a unique record of the former presence of large perennial plants. Evidence of bioturbation by burrowing animals extends more than 1 m beneath each type of plant scar, indicating that both features originated as large bioturbation mounds. Formation of bioturbation mounds in desertscrub environments is generally restricted to areas beneath widely separated, large perennial plants. The contrasting forms of plant scars (mounds vs. depressions) represent time-dependent changes following disappearance of the large plants and eventual cessation of bioturbation. Plant scar mounds represent a geologically recent episode of plant mortality, whereas plant scar depressions represent the disappearance of plants at a considerably earlier time, possibly at the Pleistocene–Holocene transition. Contrasting spatial distributions of the two kinds of plant scars indicate that vegetation on alluvial fans has progressively contracted from a more diffuse, former vegetation cover, yielding the wide, barren pavement surfaces present today. In less arid portions of the Sonoran Desert, spatial distribution of recent plant mortality due to persistent, severe drought provides an analog of the progressive loss of plants from different parts of the landscape in the past.
Ethanol inhibits palmitoylation of G protein Gαs
Authors: Hallak Hazem , Rubin Raphael 
Published: March 2006

AbstractNeurobiological actions of ethanol have been linked to perturbations in cyclic AMP (cAMP)‐dependent signaling processes. Chronic ethanol exposure leads to desensitization of cAMP production in response to physiological ligands (heterologous desensitization). Ethanol‐induced alterations in neuronal expression of G proteins Gs and Gi have been invoked as a cause of heterologous desensitization. However, effects of ethanol on G protein expression vary considerably among different experimental protocols, various brain regions and diverse neuronal cell types. Dynamic palmitoylation of G protein α subunits is critical for membrane localization and protein–protein interactions, and represents a regulatory feature of G protein function. We studied the effect of ethanol on Gαs palmitoylation. In NG108‐15 rat neuroblastoma × glioma hybrid cells, acute exposure to pharmacologically relevant concentrations of ethanol (25–100 mm) inhibited basal and prostaglandin E1‐stimulated incorporation of palmitate into Gαs. Exposure of NG108‐15 cells to ethanol for 72 h induced a shift in Gαs to its non‐palmitoylated state, coincident with an inhibition of prostaglandin E1‐induced cAMP production. Both parameters were restored following 24 h of ethanol withdrawal. Chronic ethanol exposure also induced the depalmitoylation of Gαs in human embryonic kidney (HEK)293 cells that overexpress wild‐type Gαs and caused heterologous desensitization of adenylyl cyclase. By contrast, HEK293 cells that express a non‐palmitoylated mutant of Gαs were insensitive to heterologous desensitization after chronic ethanol exposure. In summary, the findings identify a novel effect of ethanol on post‐translational lipid modification of Gαs, and represent a mechanism by which ethanol might affect adenylyl cyclase activity.
In Search of Ethnic Entrepreneurship Opportunities in the City: A Comparative Policy Study
Authors: van Delft Hadewijch , Gorter Cees , Nijkamp Peter 
Published: March 2006

The rapidly rising inflow of foreign migrants confronts policymakers with many socio-economic problems. The negative externalities of uncontrolled immigration are well known and often hard to cope with. Recent years have seen the appearance of many policy initiatives based on self-reliance principles for ethnic groups. Against this background, ethnic entrepreneurship has become a popular strategy as it stimulates and encourages migrants to look after themselves with only limited support from the government: such policies are becoming increasingly important in many large cities. In addition to the conventional educational support and training programmes, such strategies need to implement policies aimed at self-employment. An emphasis on ethnic entrepreneurship is an attempt to exploit the economic potential and opportunities of foreign migrants, instead of focusing on the problems which minorities encounter when entering the labour market. In ethnic entrepreneurship this potential can be utilised in a creative way, especially if well-organised projects and initiatives are set up. The authors compare various assistance programmes and urban policies in several European cities, which are aimed at favouring ethnic entrepreneurship, with the aim of drawing lessons for effective labour-market policies. Their approach is to employ a systematic information base concerning self-employment strategies in the cities under investigation. A newly developed comparative statistical method for categorical information, namely, rough-set analysis, is used in order to identify critical success factors. The results suggest that utilisation of social networks is most helpful in enhancing self-employment among ethnic minorities. The authors offer some lessons for the establishment of sociocultural and ethnic networks, for strategies for improving training and education, and for improving access to facilities and financial resources.
Characterization of the Plant-Specific BREVIS RADIX Gene Family Reveals Limited Genetic Redundancy Despite High Sequence Conservation
Authors: Briggs Georgette C. , Mouchel Céline F. , Hardtke Christian S. 
Published: March 2006

Abstract
To date, the function of most genes in the Arabidopsis (Arabidopsis thaliana) genome is unknown. Here we present the first analysis of the novel, plant-specific BRX (BREVIS RADIX) gene family. BRX has been identified as a modulator of root growth through a naturally occurring loss-of-function allele. The biochemical function of BRX is enigmatic, however several domains in BRX are conserved in the proteins encoded by the related BRX-like (BRXL) genes. The similarity between Arabidopsis BRXL proteins within these domains ranges from 84% to 93%. Nevertheless, analysis of brx brx-like multiple mutants indicates that functional redundancy of BRXLs is limited. This results mainly from differences in protein activity, as demonstrated by assaying the propensity of constitutively expressed BRXL cDNAs to rescue the brx phenotype. Among the genes tested, only BRXL1 can replace BRX in this assay. Nevertheless, BRXL1 does not act redundantly with BRX in vivo, presumably because it is expressed at a much lower level than BRX. BRX and BRXL1 similarity is most pronounced in a characteristic tandem repeat domain, which we named BRX domain. One copy of this domain is also present in the PRAF (PH, RCC1, and FYVE)-like family proteins. The BRX domain mediates homotypic and heterotypic interactions within and between the BRX and PRAF protein families in yeast (Saccharomyces cerevisiae), and therefore likely represents a novel protein-protein interaction domain. The importance of this domain for BRX activity in planta is underscored by our finding that expression of the C-terminal fragment of BRX, comprising the two BRX domains, is largely sufficient to rescue the brx phenotype.
Medicago truncatula Mutants Demonstrate the Role of Plant Calcium Oxalate Crystals as an Effective Defense against Chewing Insects
Authors: Korth Kenneth L. , Doege Sarah J. , Park Sang-Hyuck , Goggin Fiona L. , Wang Qin , Gomez S. Karen , Liu Guangjie , Jia Lingling , Nakata Paul A. 
Published: March 2006

Abstract
Calcium oxalate is the most abundant insoluble mineral found in plants and its crystals have been reported in more than 200 plant families. In the barrel medic Medicago truncatula Gaertn., these crystals accumulate predominantly in a sheath surrounding secondary veins of leaves. Mutants of M. truncatula with decreased levels of calcium oxalate crystals were used to assess the defensive role of this mineral against insects. Caterpillar larvae of the beet armyworm Spodoptera exigua Hübner show a clear feeding preference for tissue from calcium oxalate-defective (cod) mutant lines cod5 and cod6 in choice test comparisons with wild-type M. truncatula. Compared to their performance on mutant lines, larvae feeding on wild-type plants with abundant calcium oxalate crystals suffer significantly reduced growth and increased mortality. Induction of wound-responsive genes appears to be normal in cod5 and cod6, indicating that these lines are not deficient in induced insect defenses. Electron micrographs of insect mouthparts indicate that the prismatic crystals in M. truncatula leaves act as physical abrasives during feeding. Food utilization measurements show that, after consumption, calcium oxalate also interferes with the conversion of plant material into insect biomass during digestion. In contrast to their detrimental effects on a chewing insect, calcium oxalate crystals do not negatively affect the performance of the pea aphid Acyrthosiphon pisum Harris, a sap-feeding insect with piercing-sucking mouthparts. The results confirm a long-held hypothesis for the defensive function of these crystals and point to the potential value of genes controlling crystal formation and localization in crop plants.