bluuebunny/crossref_metadata_2025 huggingface dataset:
An examination of the 3‐factor model and structural invariance across racial/ethnic groups for the FACIT‐Sp: a report from the American Cancer Society's Study of Cancer Survivors‐II (SCS‐II)
Authors: Murphy Patricia E. , Canada Andrea L. , Fitchett George , Stein Kevin , Portier Kenneth , Crammer Corinne , Peterman Amy H.
Published: April 2009

Objectives: Recent confirmatory factor analysis (CFA) of the Functional Assessment of Chronic Illness Therapy—Spiritual Well‐Being (FACIT‐Sp) Scale in a sample of predominantly white women demonstrated that three factors, Meaning, Peace, and Faith, represented a psychometric improvement over the original 2‐factor model. The present study tested these findings in a more diverse sample, assessed the stability of the model across racial/ethnic groups, and tested the contribution of a new item.

Methods: In a study by the American Cancer Society, 8805 cancer survivors provided responses on the FACIT‐Sp, which we tested using CFA.

Results: A 3‐factor model provided a better fit to the data than the 2‐factor model in the sample as a whole and in the racial/ethnic subgroups (Δχ2, p<0.001, for all comparisons), but was not invariant across the groups. The model with equal parameters for racial/ethnic groups was a poorer fit to the data than a model that allowed these parameters to vary (Δχ2(81)=2440.54, p<0.001), suggesting that items and their associated constructs might be understood differently across racial/ethnic groups. The new item improved the model fit and loaded on the Faith factor.

Conclusions: The 3‐factor model is likely to provide more specific information for studies in the field. In the construction of scales for use with diverse samples, researchers need to pay greater attention to racial/ethnic differences in interpretation of items. Copyright © 2009 John Wiley & Sons, Ltd.
The role of acculturation in life satisfaction among Hispanic cancer survivors: results of the American Cancer Society's study of cancer survivors
Authors: Stephens Cristina , Stein Kevin , Landrine Hope
Published: April 2009

Objective: We sought to identify the role of acculturation in the life satisfaction of Hispanic cancer survivors.

Methods: We compared life satisfaction among the high‐ vs low‐acculturated Hispanics who participated in a national, cross‐sectional study of quality of life among cancer survivors.

Results: Despite fewer socio‐economic resources, low‐acculturated Hispanic survivors had higher life satisfaction (Beta=5.08, p<0.05). This relationship was mediated by higher levels of social support and spirituality found among low‐acculturated survivors, with spirituality being the strongest predictor (Beta=0.379, p<0.001).

Conclusions: Acculturation may provide opportunities for improved socio‐economic status often necessary for adequate functioning in the host culture. However, it may also result in a departure from traditional cultural values, which in turn may negatively impact life satisfaction during cancer survivorship. Copyright © 2009 John Wiley & Sons, Ltd.
Structural and functional characterization of a putative polysaccharide deacetylase of the human parasite Encephalitozoon cuniculi
Authors: Urch Jonathan E. , Hurtado‐Guerrero Ramon , Brosson Damien , Liu Zhanliang , Eijsink Vincent G. H. , Texier Catherine , van Aalten Daan M. F.
Published: April 2009

The microsporidian Encephalitozoon cuniculi is an intracellular eukaryotic parasite considered to be an emerging opportunistic human pathogen. The infectious stage of this parasite is a unicellular spore that is surrounded by a chitin containing endospore layer and an external proteinaceous exospore. A putative chitin deacetylase (ECU11_0510) localizes to the interface between the plasma membrane and the endospore. Chitin deacetylases are family 4 carbohydrate esterases in the CAZY classification, and several bacterial members of this family are involved in evading lysis by host glycosidases, through partial de‐N‐acetylation of cell wall peptidoglycan. Similarly, ECU11_0510 could be important for E. cuniculi survival in the host, by protecting the chitin layer from hydrolysis by human chitinases. Here, we describe the biochemical, structural, and glycan binding properties of the protein. Enzymatic analyses showed that the putative deacetylase is unable to deacetylate chitooligosaccharides or crystalline β‐chitin. Furthermore, carbohydrate microarray analysis revealed that the protein bound neither chitooligosaccharides nor any of a wide range of other glycans or chitin. The high resolution crystal structure revealed dramatic rearrangements in the positions of catalytic and substrate binding residues, which explain the loss of deacetylase activity, adding to the unusual structural plasticity observed in other members of this esterase family. Thus, it appears that the ECU11_0510 protein is not a carbohydrate deacetylase and may fulfill an as yet undiscovered role in the E. cuniculi parasite.
Prostate‐specific membrane antigen retargeted measles virotherapy for the treatment of prostate cancer
Authors: Liu Chunsheng , Hasegawa Kosei , Russell Stephen J. , Sadelain Michel , Peng Kah‐Whye
Published: April 2009

BACKGROUND

Live attenuated vaccine strain of measles virus (MV) has promising antitumor activity and is undergoing clinical testing in three different phase I cancer trials. The virus uses one of two receptors, CD46 which is ubiquitously expressed on all nucleated cells or CD150 which is expressed on immune cells, to infect cells. To minimize potential toxicity due to indiscriminate infection of normal cells, we have generated a fully retargeted MV that infects cells exclusively through the prostate‐specific membrane antigen (PSMA) receptor, which is overexpressed on prostate cancer cells and tumor neovasculature.

METHODS

A single‐chain antibody (scFv) specific for the extracellular domain of PSMA (J591) was inserted as a C‐terminal extension on the MV attachment protein. Specificity of infection by the PSMA targeted virus was evaluated in parallel with the parental MV and a control virus which binds to CD38, a myeloma antigen. Antitumor activity of the PSMA retargeted virus was tested in both LNCaP and PC3‐PSMA tumor xenograft models, with and without low dose external beam radiation.

RESULTS

Replication of the PSMA targeted virus was comparable to the parental MV. The PSMA scFv efficiently redirected virus infection and cytopathic killing exclusively to PSMA positive prostate cancer cells and not PSMA negative cells. There was an additive effect on cell killing from radiation treatment and virotherapy. The PSMA virus induced tumor regression of LNCaP and PC3‐PSMA tumor xenografts. Extensive areas of MV infection and apoptosis were seen in virus treated tumors.

CONCLUSIONS

The PSMA retargeted virus warrants further investigation as a virotherapy agent. Prostate 69:1128–1141, 2009. © 2009 Wiley‐Liss, Inc.
Biochemical mechanisms of methoxyfenozide resistance in the cotton leafworm Spodoptera littoralis
Authors: Mosallanejad Hadi , Smagghe Guy
Published: April 2009

BACKGROUND: Methoxyfenozide is a lepidopteran‐specific insecticide that belongs to a new group of insecticides, the non‐steroidal ecdysteroid agonists, also called moulting accelerating compounds (MACs). To investigate the risk of resistance and possible mechanisms conferring resistance to methoxyfenozide, the authors selected in the laboratory for a resistant strain of the cotton leafworm Spodoptera littoralis (Boisd.), which is a representative lepidopteran model and an important pest in cotton and vegetables worldwide, with a high risk for resistance development.

RESULTS: After selection with methoxyfenozide during 13 generations, toxicity data showed that the selected strain developed fivefold resistance to methoxyfenozide in comparison with the susceptible strain. Measurement of the detoxification enzymes demonstrated that the monooxygenase (MO) activity was 2.1 times higher in the selected strain, whereas there was no change for esterases and glutathione‐S‐transferases. When the inhibitors piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and diethyl maleate were tested as synergists, the respective synergistic ratios were 0.97, 0.96 and 1.0 for the susceptible strain, and 2.2, 0.96 and 1.1 for the resistant strain. The significant synergistic effect by PBO concurs with the increased MO activity in the selected strain.

CONCLUSION: Taken overall, the present study supports the importance of MO‐mediated metabolism in resistance to methoxyfenozide, directing tactics to fight against resistance development for this novel group of insecticides. Copyright © 2009 Society of Chemical Industry
An analysis of the persistence and potency of film‐coated seed protectant as influenced by various storage parameters
Authors: Jacob Sherry Rachel , Arunkumar MB , Gopal Madhuban , Srivastava Chitra , Sinha SN
Published: April 2009

BACKGROUND:An efficient delivery system for seed‐protectant chemicals is needed in light of several disadvantages of conventional seed treatment methods. This study evaluates the efficacy of film‐coat application in maintaining the persistence and potency of imidacloprid onLycopersicon esculentum(L.) Mill. seeds after simultaneous storage under ambient and regulated environment in paper and aluminium packages.

RESULTS:High‐performance liquid chromatography (HPLC) revealed 0.135 mg kg−1of herbage material to be the threshold value beyond which absolute control was obtained, and with film coating the latter was achieved even with half‐dosage seed treatment, irrespective of the storage condition. The technique provided early protection to the crop and also nullified the deleterious effects of ambient storage on the persistence and potency of the pesticide.

CONCLUSION:Film coating enabled superior pesticide dosage as well as higher biological efficacy to be achieved. Hence, in addition to being an ecofriendly alternative, the technique would be a more economically viable option for storage of treated seeds. Copyright © 2009 Society of Chemical Industry
Influence of surfactants on the leaching of bentazone in a sandy loam soil
Authors: Hua Rimao , Spliid Niels H , Heinrichson Kirsten , Laursen Bente
Published: April 2009

BACKGROUND: Surfactants are very often used for more efficient pesticide spraying, but knowledge about their influence on the leaching potential for pesticides is very limited. In the present study, the leaching of the herbicide bentazone [3‐isopropyl‐1H‐2, 1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide] was measured in columns with sandy loam soil with or without the addition of a non‐ionic surfactant, octylphenol ethylene oxide condensate (Triton X‐100, Triton), and an anionic surfactant, sodium dodecylbenzenesulfonate (SDBS), and in the presence of both surfactants (SDBS + Triton).

RESULTS: The mobility of bentazone (B) increased in the following order: B + Triton (slowest) < B + SDBS + Triton < B < B + SDBS (fastest). When Triton X‐100 was applied to the soil together with bentazone, the leaching of bentazone in the soil decreased significantly compared with leaching of bentazone without the addition of surfactant. SDBS and Triton X‐100 neutralised their influence on the leaching speed of bentazone in the soil columns when both surfactants were applied with bentazone.

CONCLUSION: From the study it can be concluded that, depending on their properties, surfactants can enhance or reduce the mobility of bentazone. By choosing a non‐ionic surfactant, bentazone mobility can be reduced, giving time for degradation and thereby reducing the risk of groundwater pollution. Copyright © 2009 Society of Chemical Industry
Effective anisotropy field in anisotropic nanostructured ferromagnetic materials
Authors: Yao Q. , Liu W. , Zhang Z. D.
Published: April 2009

A theoretical model has been set up to investigate analytically the effective anisotropy field of the single‐phase and anisotropic nanostructured ferromagnetic materials with uniaxial magnetocrystalline anisotropy. It is revealed that the effective anisotropy field decreases with the grain alignment by the increased deviation of the magnetization from the easy‐axis in the transition region and the enhanced suppressing effect of the intergrain exchange coupling on the anisotropy. It is suggested that magnetic properties such as the soft magnetic properties could be improved by controlling the crystallographic orientation and the intergrain or interlayer exchange coupling. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Half‐metallic ferromagnetism of MnSn compound
Authors: Wang Pei‐ji , Kao Hong , Zhang Chang‐wen , Dong Jian‐min , Zhou Zhong‐xiang
Published: April 2009

The electronic and magnetic properties of MnSn with various crystal structures are investigated by using full‐potential linearized augmented plane‐wave method within density‐functional theory. The results show that both zinc‐blende and wurtzite structure are half‐metallic with a magnetic moment 3.0μB per formula unit, whereas the NaCl and NiAs structures are of typical metallic character. The half‐metallicity is also found to be robust with respect to the lattice compression and is maintained up to the lattice constant contraction of 8% and 9% for ZB and WZ structures, respectively. Due to the robustness of half‐metallicity with respect to the lattice change and being compatible with the semiconductors, the half‐metallic ferromagnets, when realized experimentally, would be useful in spintronic and other applications. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of control charts with m‐of‐m runs rules
Authors: Lim Tae‐Jin , Cho Moonsoo
Published: April 2009

This paper investigates economic–statistical properties of the X̄ charts supplemented with m‐of‐m runs rules. An out‐of‐control condition for the chart is either a point beyond a control limit or a run of m‐of‐m successive points beyond a warning limit. The sampling process is modeled by a Markov chain with 2m states. The steady‐state probability for each state and the average run length (ARL) from each state of the Markov chain are derived in explicit formulas. Then the stationary average run length (SALR) is derived so as to develop an economic–statistical model. Using this model, the design parameters are optimized by minimizing the cost function with constraints on the average time to signal (ATS). The X̄ chart supplemented with m‐of‐m runs rules is compared with the Shewhart X̄ chart in terms of the SARL and the cost function. Sensitivity of the design parameters with respect to the cost function is also analyzed. General guidelines for implementing the X̄ chart with m‐of‐m runs rules are presented from those observations. It should be emphasized that supplementing run rules may provide feasible and efficient solutions even if the sample size is limited, while the Shewhart X̄ chart may not. Copyright © 2009 John Wiley & Sons, Ltd.
Theoretical and applicative properties of the correlation and G‐particle‐hole matrices
Authors: Valdemoro C. , Alcoba D. R. , Tel L. M. , Pérez‐Romero E.
Published: April 2009

We have recently (Valdemoro et al., Sixth International Congress of the International Society for Theoretical Chemical Physics, 2008; Alcoba et al., Int J Quantum Chem, in press) reported the form of the G‐particle‐hole hypervirial equation, which can be identified with the anti‐Hermitian part of the correlation contracted Schrödinger equation (Alcoba, Phys Rev A, 2002, 65, 032519), as a tool to obtain the second‐order reduced density matrix of an N‐electron system without previous knowledge of the wave‐function. The results which have been obtained when solving the G‐particle‐hole hypervirial equation with an iterative method also described in (Valdemoro et al., Sixth International Congress of the International Society for Theoretical Chemical Physics, 2008; Alcoba et al., Int J Quantum Chem, in press) have been highly accurate. The convergence of these test calculations has been very smooth, though rather slow. One of the factors which determines the performance of the method is the accuracy with which the 3‐order correlation matrices (3‐CM) involved in the calculations are approximated. It is, therefore, necessary to optimize to the utmost the construction algorithms of these 3‐order matrices in terms of the 2‐CM. In this article, the main theoretical features of the p‐CM are described. Also, some aspects of the correlation contracted Schrödinger equation and of the G‐particle‐hole hypervirial equation are revisited. A new theorem, concerning the sufficiency of the hypervirial of the 3‐order correlation operator to guarantee a correspondence between its solution and that of the Schrödinger equation, and some preliminary results concerning the constructing algorithms of the 3‐CM in terms of the 2‐CM, are reported in the second part of this article. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
The electronically excited states of RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine): Vertical excitations
Authors: Borges Itamar , Aquino Adélia J. A. , Barbatti Mario , Lischka Hans
Published: April 2009

The RDX molecule, hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine, is a key component for several energetic materials, which have important practical applications as explosives. A systematic study of the electronic excited states of RDX in gas phase using time‐dependent density functional theory (TDDFT), algebraic diagrammatic construction through second order method [ADC (2)], and resolution of the identity coupled‐cluster singles and doubles method (RI‐CC2) was carried out. Transition energies and optical oscillator strengths were computed for a maximum of 40 transitions. RI‐CC2 and ADC (2) predict a spectrum shaped by three intense π‐π* transitions, two with charge transfer and one with localized character. TDDFT fails in the description of the charge transfer states. The low‐energy band of the experimental UV spectrum of RDX is assigned to the first charge transfer state. Two alternative assignments of the high‐energy band are proposed. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Inverse problems in quantum chemistry
Authors: Karwowski Jacek
Published: April 2009

Inverse problems constitute a branch of applied mathematics with well‐developed methodology and formalism. A broad family of tasks met in theoretical physics, in civil and mechanical engineering, as well as in various branches of medical and biological sciences has been formulated as specific implementations of the general theory of inverse problems. In this article, it is pointed out that a number of approaches met in quantum chemistry can (and should) be classified as inverse problems. Consequently, the methodology used in these approaches may be enriched by applying ideas and theorems developed within the general field of inverse problems. Several examples, including the RKR method for the construction of potential energy curves, determining parameter values in semiempirical methods, and finding external potentials for which the pertinent Schrödinger equation is exactly solvable, are discussed in detail. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Hydrogen and silyl bridges in group 13 and 14 atom containing molecules
Authors: Petrov Klára Tarcsay , Veszprémi Tamás
Published: April 2009

Group 13 and group 14 atom containing small hydrides were investigated by quantum chemical methods to characterize their possible nonclassical bridged isomers. A robust set of methods were used like NBO analysis, topological analysis of ELF, AIM theory, several bond indices (Mayer bond order, fuzzy atoms bond order, Wiberg bond index, atom–atom overlap weighted NAO bond order), and geometry. The hydrogen bridges can be interpreted by 2 electron – 3 center bonds in NBO analysis, trisynaptic X1‐Hb‐X2valence cores in ELF, and two X‐Hbbond critical points in AIM theory. The bond orders of the X‐Hbbonds are always around half of that in a classical bond, and the sum of the bond orders for the two bridging bonds is always around one. Bonding interaction between the pillar X1‐X2atoms exists in several cases, suggested by NBO analysis, ELF, the geometry and the bond orders. In the AIM picture, however, the X1‐X2pillar bond or one of the X‐Hbbridging bond is missing. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Improving reptation quantum Monte Carlo
Authors: Yuen Wai Kong , Oblinsky Daniel G. , Giacometti Robert D. , Rothstein Stuart M.
Published: April 2009

The reptation quantum Monte Carlo (RQMC) algorithm of Baroni and Moroni (Phys Rev Lett, 1999, 82, 4745) is a recent and promising development. In this approach, one generates a large number of reptiles: sets of electron configurations arising from consecutive drift‐diffusion moves. Within the fixed‐node approximation, one extracts estimates of the exact energy from reptiles' heads and tails (their first and last configurations of electrons, respectively), and estimates expectation values for operators that do not commute with the Hamiltonian, from their middle configurations. An advantage over conceptually equivalent algorithms is that each estimate is free from population control bias. The time‐step bias, however, may accumulate, adversely affecting one's ability to accurately estimate physical properties of atoms and molecules. For this purpose we propose an alternative algorithm, “head‐tail adjusted” reptation quantum Monte Carlo, engineered to remedy this deficiency, while still simulating the target distribution for RQMC. The effectiveness of our approach is demonstrated by an application to ground‐state LiH. We estimate the fixed‐node energy with improved reliability, without adversely affecting the quality of other, nonenergy‐related properties' estimates. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
The role of basis set superposition error in water addition reactions to Ln(III) cations
Authors: Kvamme Brandon , Wander Matthew C. F. , Clark Aurora E.
Published: April 2009

Our goal in this work was to characterize the importance of basis set superposition error (BSSE) in the reaction energetics of water addition to highly charged metal ions that exhibit strong ion‐dipole interactions with water. The gas phase water addition reactions, M(H2O) + H2O → M(H2O) [M = La(III), Lu(III); N = 0–8] have been studied, with a particular emphasis on a posteriori methods for calculating BSSE and its constituent energetic components as a function of M(H2O) cluster size and water basis set. Because of accumulation of BSSE within the subclusters in the reaction series, the successive reaction counterpoise method for determining the BSSE correction interaction energies is advocated. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Mechanism of hydrogen activation by frustrated Lewis pairs: A molecular orbital approach
Authors: Hamza Andrea , Stirling András , András Rokob Tibor , Pápai Imre
Published: April 2009

A detailed molecular orbital treatment of the heterolytic hydrogen splitting by bulky Lewis acid‐base pairs is presented. The frontier molecular orbitals of the proposed reactive intermediate are shown to be preorganized but otherwise practically identical to those of the free acid and base molecules. The concerted interaction of the Lewis centers with hydrogen leading to the polarization and, ultimately, to the cleavage of the HH bond is examined, and the bridge role of hydrogen molecule in the electron transfer is pointed out. The formation of the new covalent bonds is monitored by bond order and natural localized molecular orbital calculations, and found to be synchronous. The stability of the product is interpreted on the basis of favorable orbital interactions. A comparison of various hydrogen activation mechanisms emphasizes the common donation/back‐donation motifs and the different ways of making them feasible. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Interaction of monovalent cations with acetonitrile
Authors: Černušák Ivan , Aranyosiová Monika , Vollárová Ol'Ga , Velič Dušan , Kirdajová Ol'Ga , Benko Ján
Published: April 2009

Solvation of monovalent cations (Me+) of alkali metalsNa+, K+, Rb+, and Cs+, coinage metalsCu+, Ag+, Au+, and p‐block elements Ga+, In+, and Tl+ with acetonitrile was studied by means of ab initio calculations and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). The intermolecular interactions in the complexes Me+···CH3CN were investigated using the coupled clusters theory including single, double, and noniterative triple substitutions (CCSD(T)) in conjunction with the Pol and Pol‐dk basis sets. The binding energies of these donor‐acceptor complexes were estimated; taking into account the basis set superposition error, zero‐point vibrations, correlation contribution, and scalar relativistic corrections. The theoretical ΔG0298 K values based on CCSD(T)/Pol and/or CCSD(T)/Pol‐dk binding energies correlated well with experimental transfer Gibbs energies (from water to acetonitrile) for the series of cations. In the case of Au monocation, relativistic correction turned out to be extremely important. Composition of the complex of Ag+ and Na+ with acetonitrile was determined by using SIMS supporting both theoretical and experimental transfer Gibbs energies. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Collision detection and untangling for surgical robotic manipulators
Authors: Morvan Tangui , Martinsen Magnar , Reimers Martin , Samset Eigil , Elle Ole Jakob
Published: April 2009

Background

Robotic‐assisted minimally invasive surgery provides several advantages over traditional surgery; however, it also has several drawbacks, such as possible collisions between the robotic arms and a limited field of view.

Methods

A generic method for tracking the configuration of a surgical manipulator in real time is presented. It is coupled with a collision detection and dynamic simulation algorithm, allowing the operator to detect collisions between robotic arms before they happen and presenting the best possible untangling direction to get out of collisions.

Results

Our algorithm successfully tracks the configuration of the Zeus® surgical system and accurately detects possible collisions in real time. A pilot study on our system proved its efficiency in reducing the duration and severity of collisions, at the price of longer completion times.

Conclusion

Our system helps alleviate the collision problem by reducing the time in collision. Copyright © 2009 John Wiley & Sons, Ltd.
A laboratory training and evaluation technique for computer‐aided oral implant surgery
Authors: Widmann Gerlig , Stoffner Rudolf , Keiler Martin , Zangerl Antoinette , Widmann Roland , Puelacher Wolfgang , Bale Reto
Published: April 2009

Background

Navigated oral implant surgery requires knowledge and skills in computed tomography (CT) imaging, three‐dimensional (3D) planning, and use of surgical navigation systems. To improve teaching and training, a laboratory training and evaluation technique has been developed.

Methods

The technique uses a surgical navigation system, a dental dummy and anonymous data of previously treated patients, including duplicated dental stone casts, individualized registration mouthpieces and CT scans. Training consists of definition of the prosthetic goal, 3D planning and navigated model surgery. For evaluation, a post‐surgical CT of the drilled dental stone casts is fused with the original planning CT.

Results

Each step of navigated implant surgery can be simulated and trained. Post‐surgical evaluation includes Euclidean distance, normal distance, angular deviations and damage to critical anatomical structures, such as nerves and sinuses.

Conclusions

The presented technique allows for successful laboratory training and evaluation of computer‐aided oral implant surgery. Copyright © 2009 John Wiley & Sons, Ltd.
Human cytomegalovirus targets different subsets of antigen‐presenting cells with pathological consequences for host immunity: implications for immunosuppression, chronic inflammation and autoimmunity
Authors: Varani Stefania , Frascaroli Giada , Landini Maria Paola , Söderberg‐Nauclér Cecilia
Published: April 2009

Human cytomegalovirus (HCMV) infection is a major cause of morbidity and mortality in patients with an impaired immune system. The virus itself can cause transitory but significant immunosuppression in immunocompetent as well as immunocompromised infected individuals. Besides immunosuppression, HCMV‐infected patients often develop other signs of immune dysfunction, such as autoimmune phenomena. Signs of active viral infection have also been identified in inflammatory lesions in a number of autoimmune diseases, highlighting the potential role of HCMV in the genesis or maintenance of such immunopathological phenomena. HCMV targets several cells of the immune system and subverts host immune functions to its own advantage. We present here an overview of the effects of HCMV infection on antigen‐presenting cells and relate in vitro data to immunopathological findings in HCMV‐infected patients. Possible mechanisms by which HCMV can induce host immunopathology will also be discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Adenovirus receptors: implications for tropism, treatment and targeting
Authors: Arnberg Niklas
Published: April 2009

Adenoviruses (Ads) are the most frequently used viral vectors in gene therapy and cancer therapy. Obstacles to successful clinical application include accumulation of vector and transduction in liver cells, coupled with poor transduction of target cells and tissues such as tumours. Many host molecules, including coagulation factor X, have been identified and suggested to serve as mediators of Ad liver tropism. This review summarises current knowledge concerning these molecules and the mechanisms used by Ads to bind to target cells, and considers the prospects of designing vectors that have been detargeted from the liver and retargeted to cells and tissues of interest in the context of gene therapy and cancer therapy. Copyright © 2009 John Wiley & Sons, Ltd.
Observer design for nonlinear discrete‐time systems: Immersion and dynamic observer error linearization techniques
Authors: Zhang Jian , Feng Gang , Xu Hongbing
Published: April 2009

This paper focuses on the observer design for nonlinear discrete‐time systems by means of nonlinear observer canonical form. At first, sufficient and necessary conditions are obtained for a class of autonomous nonlinear discrete‐time systems to be immersible into higher dimensional observer canonical form. Then a method called dynamic observer error linearization is developed. By introducing a dynamic auxiliary system, the augmented system is shown to be locally equivalent to the generalized observer form, whose nonlinear terms contain auxiliary states and output of the system. A constructive algorithm is also provided to obtain the state coordinate transformation. These results are an extension of their counterparts of nonlinear continuous‐time systems to nonlinear discrete‐time systems (Syst. Control Lett. 1986; 7:133–142; SIAM. J. Control Optim. 2003; 41:1756–1778; Int. J. Control 2004; 77:723–734; Automatica 2006; 42:321–328; IEEE Trans. Automat. Control 2007; 52:83–88; IEEE Trans. Automat. Control 2004; 49:1746–1750; Automatica 2006; 42:2195–2200; IEEE Trans. Automat. Control 1996; 41:598–603; Syst. Control Lett. 1997; 31:115–128). Copyright © 2009 John Wiley & Sons, Ltd.
Stability and stabilization of discrete‐time singular Markov jump systems with time‐varying delay
Authors: Ma Shuping , Boukas El‐Kébir , Chinniah Y.
Published: April 2009

The stochastic stability and stochastic stabilization of time‐varying delay discrete‐time singular Markov jump systems are discussed. For full and partial knowledge of transition probabilities cases, delay‐dependent linear matrix inequalities (LMIs) conditions for the systems to be regular, causal and stochastically stable are given. Sufficient conditions are proposed for the existence of state feedback controller in terms of LMIs. Finally, two numerical examples to illustrate the effectiveness of the method are given. Copyright © 2009 John Wiley & Sons, Ltd.
Alliance partners and firm performance: resource complementarity and status association
Authors: Lin Zhiang (John) , Yang Haibin , Arya Bindu
Published: April 2009

Bridging the resource‐based view and the institutional perspective, this study explores the performance consequences of firms' alliance partner selections by examining the interactions of resource complementarity and institutional associations (reflected through both societal and network status) between the firm and its partners. The integrative framework suggests that a joint consideration of resource complementarity and status effects, as well as important firm‐ and environmental‐level contingent factors, are critical for understanding the underlying mechanisms of alliance formations and their effects on firm performance. Further, our study suggests that it is necessary to consider both societal and network status as they can have distinct effects under certain conditions. Our analyses of four U.S. industries (computer, steel, pharmaceutics, crude petroleum and natural gas) over a span of 13 years largely support our framework. Copyright © 2009 John Wiley & Sons, Ltd.
Structural homophily or social asymmetry? The formation of alliances by poorly embedded firms
Authors: Ahuja Gautam , Polidoro Francisco , Mitchell Will
Published: April 2009

Recent research shows that preexisting network structure constrains the formation of new interorganizational alliances. Firms that are poorly embedded in a network structure are less likely than richly embedded firms to form alliances, because they lack informational and reputational benefits. This study examines the types of ties that poorly embedded firms can form to overcome the constraints that their structural positions impose, in turn helping to explain how firms' actions can transform existing network structures. We argue that poorly embedded firms are more likely to participate in ties characterized by social asymmetry than in ties characterized by structural homophily. We analyze the terms of trade that socially asymmetric partners negotiate for alliance governance and discuss how such alliances influence network dynamics. To test our arguments, we use longitudinal data on the alliance activities of 97 global chemical firms from 1979 to 1991. Copyright © 2009 John Wiley & Sons, Ltd.
Improved Hybrid Solar Cells via in situ UV Polymerization
Authors: Tepavcevic Sanja , Darling Seth B. , Dimitrijevic Nada M. , Rajh Tijana , Sibener Steven J.
Published: April 2009

One approach for making inexpensive inorganic–organic hybrid photovoltaic (PV) cells is to fill highly ordered TiO2 nanotube (NT) arrays with solid organic hole conductors such as conjugated polymers. Here, a new in situ UV polymerization method for growing polythiophene (UV‐PT) inside TiO2 NTs is presented and compared to the conventional approach of infiltrating NTs with pre‐synthesized polymer. A nanotubular TiO2 substrate is immersed in a 2,5‐diiodothiophene (DIT) monomer precursor solution and then irradiated with UV light. The selective UV photodissociation of the CI bond produces monomer radicals with intact π‐ring structure that further produce longer oligothiophene/PT molecules. Complete photoluminescence quenching upon UV irradiation suggests coupling between radicals created from DIT and at the TiO2 surface via a charge transfer complex. Coupling with the TiO2 surface improves UV‐PT crystallinity and π–π stacking; flat photocurrent values show that charge recombination during hole transport through the polymer is negligible. A non‐ideal, backside‐illuminated setup under illumination of 620‐nm light yields a photocurrent density of ≈5 µA cm2—surprisingly much stronger than with comparable devices fabricated with polymer synthesized ex situ. Since in this backside architecture setup we illuminate the cell through the Ag top electrode, there is a possibility for Ag plasmon‐enhanced solar energy conversion. By using this simple in situ UV polymerization method that couples the conjugated polymer to the TiO2 surface, the absorption of sunlight can be improved and the charge carrier mobility of the photoactive layer can be enhanced.
Ionic‐Liquid‐Assisted Sonochemical Synthesis of Carbon‐Nanotube‐Based Nanohybrids: Control in the Structures and Interfacial Characteristics
Authors: Park Ho Seok , Choi Bong Gill , Yang Seong Ho , Shin Weon Ho , Kang Jeung Ku , Jung Doohwan , Hong Won Hi
Published: April 2009

A versatile, facile, and rapid synthetic method of advanced carbon nanotube (CNT)‐based nanohybrid fabrication, or the so‐called ionic‐liquid‐assisted sonochemical method (ILASM), which combines the supramolecular chemistry between ionic liquids (ILs) and CNTs with sonochemistry for the control in the size and amount of uniformly decorated nanoparticles (NPs) and interfacial engineering, is reported. The excellence in electrocatalysis of hybrid materials with well‐designed nanostructures and favorable interfaces is demonstrated by applying them to electrochemical catalysis. The synthetic method discussed in this report has an important and immediate impact not only on the design and synthesis of functional hybrid nanomaterials by supramolecular chemistry and sonochemistry but also on applications of the same into electrochemical devices such as sensors, fuel cells, solar cells, actuators, batteries, and capacitors.
Regression testing with UML software designs: A survey
Authors: Mahdian Alireza , Andrews Anneliese Amschler , Pilskalns Orest Jacob
Published: April 2009

The unified modeling language (UML) designs come in a variety of different notations. UML designs can be quite large and interactions between various notations and the models they define can be difficult to assess. During the design phase, and between successive releases of systems, designs change. The impact of such changes and the resulting effect on behavior can be non‐obvious and difficult to assess. This survey article explores techniques for such re‐evaluation that can be classified as regression testing and suggests regression testing criteria for designs. These might vary depending on testing objectives and include both selective and regenerative regression testing approaches. The article provides a concise overview of regression testing approaches related to various UML design notations including use cases, class diagrams, sequence diagrams, activity diagrams, and statecharts, as well as combinations of these models. It discusses UML‐related techniques involving cost and prioritization during selective regression testing. Finally, it evaluates these techniques with respect to inclusiveness, precision, efficiency, generality, accountability, and safety. An example is used throughout to illustrate how the techniques work. Copyright © 2009 John Wiley & Sons, Ltd.
Fractal behaviour of complex systems
Authors: Morales‐Matamoros Oswaldo , Tejeida‐Padilla Ricardo , Badillo‐Piña Isaias
Published: April 2009

One of the most important properties of systems is complexity. In a simple way, we can define the complexity of a system in terms of the number of elements that it contains, the nature and number of interrelations and the number of levels of embeddedness. When a high level of complexity exists in a system, it is considered a complex system. Complex systems can be soft systems and hard systems. In hard systems, when their elements are interrelated in a non‐linear way, they are considered complex systems when they contain a great number of elements interacting in a non‐linear way. To try to understand the behaviour of this type of system diverse mathematical tools have been developed. A new scientific discipline with great impact in the analysis of the complex systems has been developed in recent years, called fractal analysis. The study of the complex systems in the framework of fractal theory has been recognized as a new scientific discipline, being sustained by advances that have been made in diverse fields ranging from physics to economics. In this paper the history and the basic concepts of the fractal analysis of complex systems are discussed briefly and an oil crude price volatility fractal analysis is provided. Copyright © 2009 John Wiley & Sons, Ltd.
Variables affecting physics achievement
Authors: Lawrenz Frances , Wood Nathan B. , Kirchhoff Allison , Kim Nam Keol , Eisenkraft Arthur
Published: April 2009

Much research has focused on student views about physics concepts, with an emphasis on the identification of alternative conceptions, and how curricula and professional development may ameliorate the situation. However, there has been little work on determining the extent of, and in separating, the student and teacher/classroom level variables that may impact student physics achievement. This study examined the effect of different student and teacher/classroom level variables on student understanding of physics concepts using hierarchical linear modeling (HLM), a regression based technique. The data were collected from 68 different teachers and 3,119 students who were using a reform curriculum, Active Physics. Teachers and students completed surveys asking about their beliefs, their classes and their personal characteristics. Students also completed a physics achievement test. The data show that students of teachers who used Active Physics for a greater portion of the year scored higher on the achievement test than did students of teachers who did not use the curriculum as much. Furthermore, the data show that the achievement gap was narrowed between boys and girls and between students with different attitudes toward physics. Additionally teachers who received inservice instruction on how to implement Active Physics narrowed the gap between students with different views of their classroom involvement. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 961–976, 2009
Identifying meta‐clusters of students' interest in science and their change with age
Authors: Baram‐Tsabari Ayelet , Yarden Anat
Published: April 2009

Nearly 6,000 science questions collected from five different web‐based, TV‐based and school‐based sources were rigorously analyzed in order to identify profiles of K‐12 students' interest in science, and how these profiles change with age. The questions were analyzed according to their topic, thinking level, motivation for and level of autonomy in raising the question, the object of interest and its magnitude, and psychological distance of the object in question from the asker. Characteristics of the asker, such as gender, grade level, and country of origin were also considered, alongside characteristics of the data source, such as language, setting (Internet, school, TV), and the potential science‐attentiveness of the users. Six meta‐clusters of children's and adolescents' interest in science were identified using cluster analysis of their self‐generated science questions. A developmental shift in interest from non‐classical to classical school science subjects was noted. Other age‐related developments, such as an increase in thinking level as reflected by the questions, a decrease in organization level and the psychological distance of the object in question with age were also explored. Advantages and shortcomings of web‐based data collection for educational research are discussed, as are the implications of the results obtained using this methodology for formal science education. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 999–1022, 2009
The effects of Common Knowledge Construction Model sequence of lessons on science achievement and relational conceptual change
Authors: Ebenezer Jazlin , Chacko Sheela , Kaya Osman Nafiz , Koya Satya Kiran , Ebenezer Devairakkam Luke
Published: April 2009

The purpose of this study was to investigate the effects of the Common Knowledge Construction Model (CKCM) lesson sequence, an intervention based both in conceptual change theory and in Phenomenography, a subset of conceptual change theory. A mixed approach was used to investigate whether this model had a significant effect on 7th grade students' science achievement and conceptual change. The Excretion Unit Achievement Test (EUAT) indicated that students (N = 33) in the experimental group achieved significantly higher scores (p < 0.001) than students in the control group (N = 35) taught by traditional teaching methods. Qualitative analysis of students' pre‐ and post‐teaching conceptions of excretion revealed (1) the addition and deletion of ideas from pre‐ to post‐teaching; (2) the change in the number of students within categories of ideas; (3) the replacement of everyday language with scientific labels; and (4) the difference in the complexity of students' responses from pre‐ to post‐teaching. These findings contribute to the literature on teaching that incorporates students' conceptions and conceptual change. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 25–46, 2010
Rethinking the introduction of particle theory: A substance‐based framework
Authors: Johnson Philip , Papageorgiou George
Published: April 2009

In response to extensive research exposing students' poor understanding of the particle theory of matter, this article argues that the conceptual framework within which the theory is introduced could be a limiting factor. The standard school particle model is characterized as operating within a “solids, liquids, and gases” framework. Drawing on an analysis of scientific ideas on matter and research into students' understanding, issues arising from the framework are identified which could contribute towards students' well known difficulties. The analysis leads to the proposal for a particle model based within the framework of the concept of a substance. Results from two exploratory studies using the substance‐based particle model with children (ages 9–10) in two contrasting elementary schools in England are then reported. After a short teaching intervention with a class in each school, individual interviews were held with a sample of 12 students from each class. Data were collected on students' understanding of substances coexisting in different room temperature states and phenomena involving changes of state and mixing. The results gave useful feedback on the specification of the model and its teaching. Overall the students' engagement with the particle ideas was encouraging and suggests a larger scale testing of the substance‐based model is merited. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47:130–150, 2010