bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retroviral Pseudotypes
Authors: Temperton Nigel J , Wright Edward 
Published: March 2009

Abstract

Retroviral pseudotypes are a main research and diagnostic tool of basic and clinical scientists facilitating the detailed study of individual viral genes, receptors and highly pathogenic viruses, without the need to handle live virus. Their use as gene therapy vectors is widely documented, but their other uses are less well known. The switching of envelope proteins expressed on the surface enables them to be used as surrogate viruses in neutralization/antiviral assays and for the study of cell–virus receptor interactions. However, they have recently been used as vaccine immunogens, expressing the antigen either on the pseudotype surface or as the transfer gene for stable or transient expression. Only now is their full potential being realized.

Key concepts

Students will learn:

What are retroviral pseudotypes.

How they are constructed.

The common elements that comprise a retroviral pseudotype.

How retroviral pseudotypes can be used to deliver genes.

How they can be used as tools for the study of viral attachment, entry and receptor identification.

About using pseudotypes as surrogate viruses in neutralization assays.

The use of pseudotypes to study antiviral potency and resistance.

How pseudotypes can be used as experimental vaccines.
Delay‐dependent H∞ control of linear discrete‐time systems with time‐varying delay via switched system approach
Authors: Hu Ke , Yuan Jingqi 
Published: March 2009

AbstractThis paper deals with the problem of H∞ control of linear discrete‐time systems with time‐varying delay. In order to highlight the relations between all combinations of delayed states, a general Lyapunov–Krasovskii functional is introduced, from which the relation between the switched system transformation and the classical Lyapunov–Krasovskii method is established. The basic idea is to formulate the original time‐delay systems as switched systems with arbitrary switching. Therefore, the stability and the H∞ performance problems can be reduced to the corresponding problems of such switched systems. This fact bridges two distinct research fields. Finally, numerical examples are given to illustrate the effectiveness of the method and its advantage over existing results. Copyright © 2009 John Wiley & Sons, Ltd.
Sliding mode control for a class of uncertain nonlinear system based on disturbance observer
Authors: Chen Mou , Chen Wen‐Hua 
Published: March 2009

AbstractIn this paper, a sliding mode control (SMC) scheme is proposed for a class of nonlinear systems based on disturbance observers. For a nonlinear system, the disturbance that cannot be directly measured is estimated using a nonlinear disturbance observer. By choosing an appropriate nonlinear gain function, the disturbance observer can well approximate the unknown disturbance. Based on the output of the disturbance observer, an SMC scheme is presented for the nonlinear system, and the stability of the closed‐loop system is established using Lyapunov method. Finally, two simulation examples are presented to illustrate the features and the effectiveness of the proposed disturbance‐observer‐based SMC scheme. Copyright © 2009 John Wiley & Sons, Ltd.
Adaptive neural network output feedback stabilization of nonlinear non‐minimum phase systems
Authors: Hoseini S. M. , Farrokhi M. , Koshkouei A. J. 
Published: March 2009

AbstractThis paper presents an adaptive output feedback stabilization method based on neural networks (NNs) for nonlinear non‐minimum phase systems. The proposed controller comprises a linear, a neuro‐adaptive, and an adaptive robustifying parts. The NN is designed to approximate the matched uncertainties of the system. The inputs of the NN are the tapped delays of the system input–output signals. In addition, an appropriate reference signal is proposed to compensate the unmatched uncertainties inherent in the internal system dynamics. The adaptation laws for the NN weights and adaptive gains are obtained using Lyapunov's direct method. These adaptation laws employ a linear observer of system dynamics that is realizable. The ultimate boundedness of the error signals are analytically shown using Lyapunov's method. The effectiveness of the proposed scheme is shown by applying to a translation oscillator rotational actuator model. Copyright © 2009 John Wiley & Sons, Ltd.
Identification of the inertia matrix of a rotating body based on errors‐in‐variables models
Authors: Jun Byung‐Eul , Bernstein Dennis S. , McClamroch N. Harris 
Published: March 2009

AbstractThis paper proposes a procedure for identifying the inertia matrix of a rotating body. The procedure based on Euler's equation governing rotational motion assumes errors‐in‐variables models in which all measurements, torque as well as angular velocities, are corrupted by noises. In order for consistent estimation, we introduce an extended linear regression model by augmenting the regressors with constants and the parameters with noise‐contributed terms. A transformation, based on low‐pass filtering, of the extended model cancels out angular acceleration terms in the regressors. Applying the method of least correlation to the model identifies the elements of the inertia matrix. Analysis shows that the estimates converge to the true parameters as the number of samples increases to infinity. Monte Carlo simulations demonstrate the performance of the algorithm and support the analytical consistency. Copyright © 2009 John Wiley & Sons, Ltd.
Reversible and High‐Capacity Nanostructured Electrode Materials for Li‐Ion Batteries
Authors: Kim Min Gyu , Cho Jaephil 
Published: March 2009

AbstractReversible nanostructured electrode materials are at the center of research relating to rechargeable lithium batteries, which require high power, high capacity, and high safety. The higher capacities and higher rate capabilities for the nanostructured electrode materials than for the bulk counterparts can be attributed to the higher surface area, which reduces the overpotential and allows faster reaction kinetics at the electrode surface. These electrochemical enhancements can lead to versatile potential applications of the batteries and can provide breakthroughs for the currently limited power suppliers of mobile electronics. This Feature Article describes recent research advances on nanostructured cathode and anode materials, such as metals, metal oxides, metal phosphides and LiCoO2, LiNi1–xMxO2 with zero‐, one‐, two‐, and three‐dimensional morphologies.
Soluble endoglin modulates aberrant cerebral vascular remodeling
Authors: Chen Yongmei , Hao Qi , Kim Helen , Su Hua , Letarte Michelle , Karumanchi S. Ananth , Lawton Michael T. , Barbaro Nicholas M. , Yang Guo‐Yuan , Young William L. 
Published: March 2009

AbstractObjectiveBrain arteriovenous malformations (AVMs) are an important cause of neurological morbidity in young adults. The pathophysiology of these lesions is poorly understood. A soluble form of endoglin (sEng) has been shown to cause endothelial dysfunction and induce preeclampsia. We tested if sEng would be elevated in brain AVM tissues relative to epilepsy brain tissues, and also investigated whether sEng overexpression via gene transfer in the mouse brain would induce vascular dysplasia and associated changes in downstream signaling pathways.MethodsExpression levels of sEng in surgical specimens were determined by Western blot assay and enzyme‐linked immunosorbent assay. Vascular dysplasia, levels of matrix metalloproteinase (MMP), and oxidative stress were determined by immunohistochemistry and gelatin zymography.ResultsBrain AVMs (n = 33) had higher mean sEng levels (245 ± 175 vs 100 ± 60, % of control, p = 0.04) compared with controls (n = 8), as determined by Western blot. In contrast, membrane‐bound Eng was not significantly different (108 ± 79 vs 100 ± 63, % of control, p = 0.95). sEng gene transduction in the mouse brain induced abnormal vascular structures. It also increased MMP activity by 490 ± 30% (MMP‐9) and 220 ± 30% (MMP‐2), and oxidants by 260 ± 20% (4‐hydroxy‐2‐nonenal) at 2 weeks after injection, suggesting that MMPs and oxidative radicals may mediate sEng‐induced pathological vascular remodeling.InterpretationThe results suggest that elevated sEng may play a role in the generation of sporadic brain AVMs. Our findings may provide new targets for therapeutic intervention for patients with brain AVMs. Ann Neurol 2009;66:19–27
Inhibitory actions of the gamma‐aminobutyric acid in pediatric Sturge‐Weber syndrome
Authors: Tyzio Roman , Khalilov Ilgam , Represa Alfonso , Crepel Valerie , Zilberter Yuri , Rheims Sylvain , Aniksztejn Laurent , Cossart Rosa , Nardou Romain , Mukhtarov Marat , Minlebaev Marat , Epsztein Jérôme , Milh Mathieu , Becq Helene , Jorquera Isabel , Bulteau Christine , Fohlen Martine , Oliver Viviana , Dulac Olivier , Dorfmüller Georg , Delalande Olivier , Ben‐Ari Yehezkel , Khazipov Roustem 
Published: March 2009

AbstractObjectiveThe mechanisms of epileptogenesis in Sturge‐Weber syndrome (SWS) are unknown. We explored the properties of neurons from human pediatric SWS cortex in vitro and tested in particular whether gamma‐aminobutyric acid (GABA) excites neurons in SWS cortex, as has been suggested for various types of epilepsies.MethodsPatch‐clamp and field potential recordings and dynamic biphoton imaging were used to analyze cortical tissue samples obtained from four 6‐ to 14‐month‐old pediatric SWS patients during surgery.ResultsNeurons in SWS cortex were characterized by a relatively depolarized resting membrane potential, as was estimated from cell‐attached recordings of N‐methyl‐D‐aspartate channels. Many cells spontaneously fired action potentials at a rate proportional to the level of neuronal depolarization. The reversal potential for GABA‐activated currents, assessed by cell‐attached single channel recordings, was close to the resting membrane potential. All spontaneously firing neurons recorded in cell‐attached mode or imaged with biphoton microscopy were inhibited by GABA. Spontaneous epileptiform activity in the form of recurrent population bursts was suppressed by glutamate receptor antagonists, the GABA(A) receptor agonist isoguvacine, and the positive allosteric GABA(A) modulator diazepam. Blockade of GABA(A) receptors aggravated spontaneous epileptiform activity. The NKCC1 antagonist bumetanide had little effect on epileptiform activity.InterpretationSWS cortical neurons have a relatively depolarized resting membrane potential and spontaneously fire action potentials that may contribute to increased network excitability. In contrast to previous data depicting excitatory and proconvulsive actions of GABA in certain pediatric and adult epilepsies, GABA plays mainly an inhibitory and anticonvulsive role in SWS pediatric cortex. Ann Neurol 2009;66:209–218
Effect of chorioamnionitis on brain development and injury in premature newborns
Authors: Chau Vann , Poskitt Kenneth J. , McFadden Deborah E. , Bowen‐Roberts Tim , Synnes Anne , Brant Rollin , Sargent Michael A. , Soulikias Wendy , Miller Steven P. 
Published: March 2009

AbstractObjectiveThe association of chorioamnionitis and noncystic white matter injury, a common brain injury in premature newborns, remains controversial. Our objectives were to determine the association of chorioamnionitis and postnatal risk factors with white matter injury, and the effects of chorioamnionitis on early brain development, using advanced magnetic resonance imaging.MethodsNinety‐two preterm newborns (24–32 weeks gestation) were studied at a median age of 31.9 weeks and again at 40.3 weeks gestation. Histopathological chorioamnionitis and white matter injury were scored using validated systems. Measures of brain metabolism (N‐acetylaspartate/choline and lactate/choline) on magnetic resonance spectroscopy, and microstructure (average diffusivity and fractional anisotropy) on diffusion tensor imaging were calculated from predefined brain regions.ResultsThirty‐one (34%) newborns were exposed to histopathological chorioamnionitis, and 26 (28%) had white matter injury. Histopathological chorioamnionitis was not associated with an increased risk of white matter injury (relative risk: 1.2; p = 0.6). Newborns with postnatal infections and hypotension requiring therapy were at higher risk of white matter injury (p < 0.03). Adjusting for gestational age at scan and regions of interest, histopathological chorioamnionitis did not significantly affect brain metabolic and microstructural development (p > 0.1). In contrast, white matter injury was associated with lower N‐acetylaspartate/choline (−8.9%; p = 0.009) and lower white matter fractional anisotropy (−11.9%; p = 0.01).InterpretationHistopathological chorioamnionitis does not appear to be associated with an increased risk of white matter injury on magnetic resonance imaging or with abnormalities of brain development. In contrast, postnatal infections and hypotension are associated with an increased risk of white matter injury in the premature newborn. Ann Neurol 2009;66:155–164
A simulated auto‐thermal membrane reformer process for a PEM fuel cell micro cogeneration unit
Authors: Ersöz Atilla 
Published: March 2009

AbstractThere are several methods of producing hydrogen‐rich gas from fossil resources such as natural gas or naphtha, for example, steam reforming, partial oxidation and auto‐thermal reforming. In this paper, an integrated ATR membrane reactor system was simulated. The effect of operating parameters on the product distribution, fuel cell hydrogen utilization and the net electric efficiency of the overall system were discussed. The overall system was integrated with a 1‐kWe PEM fuel cell. The ASPEN‐HYSIS 3.2 software has been utilized for the simulations and calculations of the fuel processing reactions. Natural gas fuel has been used as feedstock and applied to the simulated flow‐sheet model. It was desired to produce hydrogen‐rich gas with a low CO formation using an autothermal membrane reformer. A very low CO content with higher content of hydrogen was provided by the membrane reformer, eliminating the use of the conventional preferential oxidation (PrOx) reactor. Different combinations of TATR, S/C, O2/C ratios and UH2 have been parametrically studied. Fuel processing efficiency and net electrical efficiency of all selected operating conditions have been calculated as well. Results indicate that the system parameters are very critical for the appropriate operation of the residential cogeneration system with ATR membrane unit. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Membrane bioreactors: overview of the effects of module geometry on mixing energy
Authors: Wang Yuan , Brannock Matthew , Leslie Greg 
Published: March 2009

AbstractMembranes used in municipal membrane bioreactor (MBR) plants can be configured as flat sheet (FS) membranes or hollow fibre (HF) membranes. The HFs can be mounted either horizontally or vertically. The membranes can be immersed in their own vessel or within the aerobic vessel. These various configurations combine to give a unique reactor design. Current methods of design assume the mixing characteristics (e.g. each reactor vessel is completely mixed); hence the energy necessary to achieve complete mixing cannot be optimised. This paper presents an overview of mixing studies undertaken by the authors' research group on pilot‐ and full‐scale MBRs through residence time distribution (RTD) analysis and computational fluid dynamics (CFD) modelling. The drawbacks of current technique for the sizing of MBRs (e.g. compartmental modelling) are highlighted. The use of CFD as a design tool to evaluate the mixing and energy of MBRs with different configurations (e.g. HF vs FS, inside submerged vs outside submerged) is presented. The MBR CFD model was validated using field‐measured RTD data and compared with compartmental model. Results from mixing studies suggest that HF membranes are more energy efficient in terms of creating completely mixed conditions than the FS membranes. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Transport characteristics of L‐citrulline in renal apical membrane of proximal tubular cells
Authors: Mitsuoka Keisuke , Shirasaka Yoshiyuki , Fukushi Akimasa , Sato Masanobu , Nakamura Toshimichi , Nakanishi Takeo , Tamai Ikumi 
Published: March 2009

AbstractL‐Citrulline has diagnostic potential for renal function, because its plasma concentration increases with the progression of renal failure. Although L‐citrulline extracted by glomerular filtration in kidney is mostly reabsorbed, the mechanism involved is not clearly understood. The present study was designed to characterize L‐citrulline transport across the apical membranes of renal epithelial tubular cells, using primary‐cultured rat renal proximal tubular cells, as well as the human kidney proximal tubular cell line HK‐2. L‐Citrulline was transported in a Na+‐dependent manner from the apical side of both cell types cultured on permeable supports with a microporous membrane. Kinetic analysis indicated that the transport involves two distinct Na+‐dependent saturable systems and one Na+‐independent saturable system in HK‐2 cells. The uptake was competitively inhibited by neutral and cationic, but not anionic amino acids. Relatively large cationic and anionic compounds inhibited the uptake, but smaller ones did not. In HK‐2 cells, mRNA expression of SLC6A19 and SLC7A9, which encode B0AT1 and b0,+AT, respectively, was detected by RT‐PCR. In addition, L‐citrulline transport was significantly decreased in HK‐2 cells in which either SLC6A19 or SLC7A9 was silenced. Hence, these results suggest that amino acid transporters B0AT1 and b0,+AT are involved in the reabsorption of L‐citrulline in the kidney, at least in part, by mediating the apical membrane transport of L‐citrulline in renal tubule cells. Copyright © 2009 John Wiley & Sons, Ltd.
Boundaries of Britishness in British Indian and Pakistani young adults
Authors: Vadher Kiren , Barrett Martyn 
Published: March 2009

AbstractThis study explored what it means to be British from the perspective of young British Indian and Pakistani adults. Fifteen respondents were interviewed using a semi‐structured schedule in order to explore their self‐descriptions and self‐categorizations, how different contexts influence their identifications as British and as Indian/Pakistani, their sense of patriotism, and their perceptions of racism, discrimination and multiculturalism. Grounded theory methodology was used to analyse the interviews. The respondents' identifications and the role of context, threat and racism were studied in detail, and a model of how these individuals defined the boundaries of Britishness, and how they positioned themselves in relationship to these boundaries, was derived from the data. Six boundaries of Britishness were identified, these being the racial, civic/state, instrumental, historical, lifestyle and multicultural boundaries. Participants used these boundaries flexibly, drawing on different boundaries depending on the particular context in which Britishness was discussed. The implications of these multiple boundaries for the conceptualization of national identification are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Environmental representations of local communities' spokespersons in protected areas
Authors: Hovardas Tasos , Korfiatis Konstantinos J. , Pantis John D. 
Published: March 2009

AbstractDespite the popularization of the environmental discourse, rural environmental belief‐systems should not be viewed as homogenous. Focusing on the largest protected area in Greece, we examined heterogeneity in local environmental views. Local spokespersons elicited word associations to two stimulus terms, namely, ‘environmentalists’ and ‘protected area’. Based on association categories for both terms, we identified two sample segments. ‘Naturalists’ appealed to a naturalistic image, which shaped the core compartment of their representations. On the other hand, ‘skeptics’ provided both environmentalist claims and critical accounts. Our findings revealed that the environmental discourse was widely diffused among local spokespersons. Issues of power and participation in decision‐making processes within protected areas are discussed. For instance, dimensions of power and legitimacy were reflected in the frequency of association categories and their allocation among sample segments. Specifically, environmentalist accounts were overtly expressed by both ‘naturalists’ and skeptics, while a more socially, politically and critically inclined view was revealed by a small percentage of associations that were all elicited by ‘skeptics’. We conclude that appreciating the heterogeneity of rural environmental views can reinforce the democratic mandate in environmental policy‐making. Copyright © 2009 John Wiley & Sons, Ltd.
Detection of Biologically Important Anions in Aqueous Media by Dicationic Azaborines Bearing Ammonio or Phosphonio Groups
Authors: Agou Tomohiro , Sekine Masaki , Kobayashi Junji , Kawashima Takayuki 
Published: March 2009

AbstractNot common sense, but specific: Dicationic azaborines bearing ammonio or phosphonio groups showed enhanced Lewis acidity as well as improved water solubility. Complexation between the azaborines and fluoride or cyanide ions was observed in aqueous media (see figure; DMSO= dimethyl sulfoxide).magnified imageNew cationic triarylboranes bearing ammonio or phosphonio groups on the periphery were synthesized from a common intermediate, a dibromodibenzoazaborine. These cationic molecules are soluble in highly polar organic solvents as well as water, and they exhibit strong light absorption and photoluminescence emission in water. Complexation of the cationic azaborines with fluoride and cyanide ions in aqueous media proceeded and could be monitored by NMR, UV/Vis, and fluorescence spectroscopy.
On the Reaction of Glycerol Dehydratase with But‐3‐ene‐1,2‐diol
Authors: Sandala Gregory M. , Kovačević Borislav , Barić Danijela , Smith David M. , Radom Leo 
Published: March 2009

AbstractIntriguing inactivation: Calculations suggest that the ability of relatively high‐energy radical intermediates to inactivate glycerol dehydratase (GDH) may reflect a general and hitherto unidentified inactivation mechanism in the reaction of coenzyme B12‐dependent enzymes and 3‐unsaturated 1,2‐diols (see scheme; AdoCbl: adenosylcobalamin or coenzyme B12).magnified imageHigh‐level conventional ab initio and density functional theory (DFT) calculations have been performed to examine the fate of the native substrate glycerol (1) and its analogue but‐3‐ene‐1,2‐diol (7) in the coenzyme B12‐dependent enzyme glycerol dehydratase (GDH). Experimental studies find that 7 irreversibly inactivates GDH, though the mechanism for the inactivation remains unknown. Interestingly, the EPR data suggest that the spin density for an observed radical is located in the vicinity of the C1 atom, which has been interpreted to indicate termination of the pathway at the substrate‐derived radical 8. Our calculations show that if analogue 7 were to follow a similar mechanistic pathway to that followed by 1, then the reaction would be unlikely to stop at 8 but would rather proceed to the highly stabilized product‐related radical 9. However, the EPR characteristics of 9 would not be consistent with the observed EPR data. Calculations involving an initial H‐atom abstraction from the C2 position of 7 identify alternative radicals that might account for the EPR data, though they are of relatively high energy. A proposal that could explain the experimental observations is that the enzyme binds 7 in such a manner as to prevent the efficient transformation of 8. Recent work with the related enzyme diol dehydratase suggests that a common, but as yet unexplained, inactivation mechanism may be operative for both enzymes. Finally, we note the good overall performance of the MPWB1K, BMK, M05‐2X, and B2‐PLYP DFT procedures for these reactions, with the BMK method producing the best results.