bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and fracture behavior of semicrystalline polymer–clay nanocomposites
Authors: Vu Hong‐Nga , Vermogen Alexandre , Gauthier Catherine , Masenelli‐Varlot Karine , Cavaillé Jean‐Yves
Published: July 2008

The relationships between the microstructure and the fracture behavior of three polymer/clay nanocomposites were studied. Two different polymer matrices were chosen, namely polyamide‐6 and polyethylene (compatibilized with PE‐g‐MA or PE‐g‐PEo), to reach very different clay dispersion states. The microstructure was characterized in terms of polymer crystallinity, orientation of the polymer crystalline lamellae, clay dispersion state, and orientation of the clay tactoids. The mechanical behavior was characterized by tensile tests. The essential work of fracture (EWF) concept was used to determine the fracture behavior of the nanocomposites. Both tensile and EWF tests were performed in two perpendicular directions, namely longitudinal and transversal. It is shown that the fracture behaviors of the matrices mainly depend on the polymer crystalline lamellae orientation. For the nanocomposites, the relationships between the matrix orientation, the clay dispersion states, the values of the EWF parameters (we and βwp), and their anisotropy are discussed. The results show that the lower the average clay tactoid thickness, the lower is the decrease of fracture performance for the nanocomposite and the more consumed energy as longer the path of the crack. Besides, a linear dependence of the anisotropy of the EWF parameters of the nanocomposites on the average clay aspect ratio is found. The more exfoliated the structure is, the less pronounced the anisotropy of the EWF parameters. Interestingly, it is thought that the average clay aspect ratio is the parameter representing the clay dispersion state that governs the fracture anisotropy of the nanocomposites (as the elastic properties determined by tensile tests). © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1820–1836, 2008
Social‐cognitive aspects of underserved Latinas preparing to undergo genetic cancer risk assessment for hereditary breast and ovarian cancer
Authors: Lagos Veronica I. , Perez Martin A. , Ricker Charité N. , Blazer Kathleen R. , Santiago Nydia M. , Feldman Nancy , Viveros Lori , Weitzel Jeffrey N.
Published: July 2008

Objectives: As Latinos are a growing ethnic group in the United States, it is important to understand the socio‐cultural factors that may be associated with cancer screening and prevention in this population. The socio‐cultural factors that may affect preparedness to undergo genetic cancer risk assessment (GCRA) deserve particular attention. The pre‐GCRA period can provide insight into variables that may influence how medically underserved Latinas, with limited health resources and access, understand hereditary cancer information and subsequently implement cancer risk management recommendations. This study explores social, cognitive and cultural variables in Latinas prior to undergoing GCRA.

Methods: The study sample consisted of low‐income, underserved Latinas referred for GCRA because of a personal and/or family history of breast or ovarian cancer. Acculturation, cancer‐specific fatalism, self‐efficacy and social support were assessed prior to GCRA.

Results: Fifty Latinas (mean age=40.1±7.7) completed instruments; 86% had invasive cancer, 78% spoke primarily Spanish and 61% were of Mexican ancestry. Low levels of acculturation (n=50, mean=9.0±5.8) and cancer‐specific fatalism (n=43, mean=5.6±3.2), but relatively high self‐efficacy (n=49, mean=40.9±7.8) and social support (n=49, mean=37.3±8.7) were reported. Cancer‐specific fatalism and self‐efficacy were inversely correlated (r=−0.47, p=0.002). Those over age 38 at the time of cancer diagnosis reported higher acculturation (mean=11.4±7.2, p=0.02) and social support (mean=40.5±1.2, p=0.05).

Conclusions: These findings suggest that medically underserved Latinas may already possess some of the necessary skills to successfully approach the GCRA process, but that special attention should be given to cultural factors. Copyright © 2008 John Wiley Sons, Ltd.
Discrimination of Penicillium isolates by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry fingerprinting
Authors: Hettick Justin M. , Green Brett J. , Buskirk Amanda D. , Kashon Michael L. , Slaven James E. , Janotka Erika , Blachere Francoise M. , Schmechel Detlef , Beezhold Donald H.
Published: July 2008

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) was used to generate highly reproducible mass spectral ‘fingerprints’ for twelve Penicillium species. Prior to MALDI‐TOF MS analysis, eight replicate cultures of each Penicillium species were subjected to three one‐minute bead‐beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contained abundant peaks in the range of m/z 5000–20 000, and allowed unambiguous discrimination between species. In addition, a biomarker common to all Penicillium mass spectra was observed at m/z 13 900. Discriminant analysis using the MALDI‐TOF MS data yielded classification error rates of 0% (i.e. 100% correct identification), indicating that MALDI‐TOF MS data may be a useful diagnostic tool for the objective identification of Penicillium species of environmental and clinical importance. Published in 2008 by John Wiley & Sons, Ltd.
ExponentialH∞filtering for switched linear systems with interval time‐varying delay
Authors: Wang Dong , Wang Wei , Shi Peng
Published: July 2008

This paper deals with the problem of exponentialH∞filtering for a class of continuous‐time switched linear system with interval time‐varying delay. The time delay under consideration includes two cases: one is that the time delay is differentiable and bounded with a constant delay‐derivative bound, whereas the other is that the time delay is continuous and bounded. Switched linear filters are designed to ensure that the filtering error systems under switching signal with average dwell time are exponentially stable with a prescribedH∞noise attenuation level. Based on the free‐weighting matrix approach and the average dwell technology, delay‐dependent sufficient conditions for the existence of such a filter are derived and formulated in terms of linear matrix inequalities (LMIs). By solving that corresponding LMIs, the desired filter parameterized matrices and the minimal average dwell time are obtained. Finally, two numerical examples are presented to demonstrate the effectiveness of the developed results. Copyright © 2008 John Wiley & Sons, Ltd.
Fault‐tolerant control synthesis for a class of nonlinear systems: Sum of squares optimization approach
Authors: Ma Hong‐Jun , Yang Guang‐Hong
Published: July 2008

This paper studies the fault‐tolerant control (FTC) problem for nonlinear systems, with guaranteed cost orH∞performance objective in the presence of actuator faults. The faulty mode is built as a multi‐model framework of the typical aberration in actuator effectiveness. The novelty of this paper is that the effect of the nonlinear terms is described as an index in order to transform the FTC design problem into a semi‐definite programming. The proposed optimization approach is to find zero optimum for this index. Combined with other performance indexes, the conceived multi‐objective optimization problem is solved by using sum of squares method in a reliable and efficient manner. Numerical examples are included to verify the applicability of this new approach for the nonlinear FTC synthesis. Copyright © 2008 John Wiley & Sons, Ltd.
Robust adaptive control for a class of uncertain strict‐feedback nonlinear systems
Authors: Hong F. , Ge S. S. , Ren B. , Lee T. H.
Published: July 2008

In this paper, robust adaptive control is presented for a class of perturbed strict‐feedback nonlinear systems with both completely unknown control coefficients and parametric uncertainties. The proposed design method does not require the a priori knowledge of the signs of the unknown control coefficients. For the first time, the key technical Lemma is proven when the Nussbaum function is chosen by N(ζ)=ζ2cos(ζ), based on which the proposed robust adaptive scheme can guarantee the global uniform ultimate boundedness of the closed‐loop system signals. Simulation results show the validity of the proposed scheme. Copyright © 2008 John Wiley & Sons, Ltd.
H∞ control for discrete‐time Markovian jump linear systems with partly unknown transition probabilities
Authors: Zhang Lixian , Boukas El‐Kébir
Published: July 2008

In this paper, the problem of H∞ control for a class of discrete‐time Markovian jump linear system with partly unknown transition probabilities is investigated. The class of systems under consideration is more general, which covers the systems with completely known and completely unknown transition probabilities as two special cases. Moreover, in contrast to the uncertain transition probabilities studied recently, the concept of partly unknown transition probabilities proposed in this paper does not require any knowledge of the unknown elements. The H∞ controllers to be designed include state feedback and dynamic output feedback, since the latter covers the static one. The sufficient conditions for the existence of the desired controllers are derived within the matrix inequalities framework, and a cone complementary linearization algorithm is exploited to solve the latent equation constraints in the output‐feedback control case. Two numerical examples are provided to show the validness and potential of the developed theoretical results. Copyright © 2008 John Wiley & Sons, Ltd.
LMI approach to reliable guaranteed cost control with multiple criteria constraints: The actuator faults case
Authors: Zhang Dengfeng , Su Hongye , Pan Shuwen , Chu Jian , Wang Zhiquan
Published: July 2008

Based on the multi‐objective optimization strategy and linear matrix inequality approach, the problem of reliable guaranteed cost control with multiple criteria constraints is investigated for a class of uncertain discrete‐time systems subject to actuator faults. A fault model in actuators, which considers outage or partial degradation in independent actuators, is adopted. The quadratic stability is proved to be independent of the disturbance and the upper bound of a quadratic cost index is improved. The reliable feedback controller is designed to minimize the upper bound of the quadratic cost index, place all the closed‐loop poles in a specified disk, constrain theH∞norm level of the disturbance attenuation into a given range and guarantee the magnitudes of control inputs less than the given bound, as well. Thus, the resulting closed‐loop system can provide satisfactory stability, transient behavior, disturbance rejection level and optimized upper bound of the quadratic cost performance despite possible actuator faults. Copyright © 2008 John Wiley & Sons, Ltd.
Non‐diagonal MIMO QFT controller design reformulation
Authors: Garcia‐Sanz Mario , Eguinoa Irene , Bennani Samir
Published: July 2008

This paper presents a reformulation of the full‐matrix quantitative feedback theory (QFT) robust control methodology for multiple‐input–multiple‐output (MIMO) plants with uncertainty. The new methodology includes a generalization of previous non‐diagonal MIMO QFT techniques; avoiding former hypotheses of diagonal dominance; simplifying the calculations for the off‐diagonal elements, and then the method itself; reformulating the classical matrix definition of MIMO specifications by designing a new set of loop‐by‐loop QFT bounds on the Nichols Chart, which establish necessary and sufficient conditions; giving explicit expressions to share the load among the loops of the MIMO system to achieve the matrix specifications; and all for stability, reference tracking, disturbance rejection at plant input and output, and noise attenuation problems. The new methodology is applied to the design of a MIMO controller for a spacecraft flying in formation in a low Earth orbit. Copyright © 2008 John Wiley & Sons, Ltd.
Spiritual development and camp experiences
Authors: Henderson Karla A. , Bialeschki M. Deborah
Published: July 2008

Camps have long addressed multiple components of young people's development, including spiritual development. In particular, transcendental communion with nature and the outdoors may provide one pathway for young people's spiritual development.
Spiritual development with marginalized youth: A status report
Authors: Wilson Melanie , Nicholson Kristal S.
Published: July 2008

Efforts to clarify the appropriate uses of spirituality programming with marginalized youth are under way. Some researchers suggest that such programs should consider spiritual exploration and growth as a core part of treatment, involve youth voluntarily and as decision makers, and align programming with youth's cultural experiences.
An Unusual Presentation of Acute Calcific Tendinitis in the Hand
Authors: Harris Albert R. , McNamara Terrence R. , Brault Jeffrey S. , Rizzo Marco
Published: July 2008

Acute calcific tendinitis (ACT) is a relatively uncommon disorder of the hand and wrist. ACT is a well-known condition of the shoulder, but it often goes unrecognized when occurring in the hand or wrist. The overall lack of familiarity along with the non-specific symptoms associated with ACT frequently leads to misdiagnosis or delay in diagnosis. We report a case of acute calcific tendinitis occurring in the carpal tunnel which is a rare presentation.
Common factors in international securitized real estate markets
Authors: Liow Kim Hiang , Webb James R.
Published: July 2008

This study investigates the presence of common factors in the securitized real estate markets of the Untied States (US), United Kingdom (UK), Hong Kong (HK), and Singapore (SG). Using a combination of factor analysis and canonical correlation analysis on 10‐year monthly return data for 142 real estate securities in the four markets, more common risk factors among real estate securities within a country than across countries are detected. In addition, there is at least one common securitized real estate market factor that is moderately correlated with the world real estate market, and to a lesser extent, with the world stock market. However, the degree of linkage across the four securitized real estate markets is much weaker than the strong linkages present across the four economies. It further appears that the extent to which correlations are found in international securitized real estate markets might largely be due to the increasing integrated nature of the world real economy, rather than a result of the globalization of financial markets. The results are preliminary, but indicative, and suggest that more studies exploring how common factors, together with the local market portfolio, could help explain the return‐generating process of securitized real estate.
Kinematic and thermal constraints on the reactivation of the Outer Hebrides Fault Zone, NW Scotland
Authors: SZULC A. G. , ALSOP G. I. , OLIVER G. J. H.
Published: July 2008

The Outer Hebrides Fault Zone is a major easterly dipping reactivated shear zone which displaces Lewisian gneiss of the Laurentian craton, NW Scotland. Despite a number of detailed field studies, the fault zone remains poorly understood with regard to both its age of inception and precise conditions of reactivation. The island of Scalpay in the northern portion of the Outer Hebrides Fault Zone provides exceptional exposures through a variety of reactivated fault rock types and therefore represents an ideal location to investigate fault zone evolution via fluid inclusion studies of syn-tectonic quartz veins. This fluid inclusion study constrains reactivation temperatures more precisely than hitherto possible with top-to-the-NW ductile thrusting occurring at 500 ± 30°C. Subsequent phyllonitization is associated with oblique sinistral top-to-the-NE strike-slip at 230 ± 20°C, followed by a discrete system of top-to-the-NE/SE extensional detachments at 150 ± 20°C. Other recent fluid inclusion studies in the southern portion of the Outer Hebrides Fault Zone constrain phyllonitization associated with top-to-the-E displacement to 370 ± 20°C, with subsequent top-to-the-NE extensional detachments operating at 150–210°C. Thus, late-stage extensional detachment systems record consistent conditions of reactivation along the strike length of the Outer Hebrides Fault Zone. However, our results also clearly emphasize that conditions of earlier fault zone reactivation and phyllonitization were highly heterogeneous between the northern and southern portions, thus suggesting a spatial and temporal variation in the deformation and/or fluid flux system.
Star Academy as Arab Political Satire
Authors: Kraidy Marwan M.
Published: July 2008

The previous excerpt is taken from a column by Syrian journalist Hakam al-Baba, published in the London-based Pan-Arab newspaper al-Quds al-ʿArabi. Al-Baba, a middle-aged Syrian journalist known for his biting sarcasm, has written some of the most perceptive critiques of Syrian and Arab media, including a famous 2005 article in the Syrian daily Tishreen, in which he relates his experience of harassment by the mukhābarāt. In the excerpted column, al-Baba uses the raging Pan-Arab controversies over reality TV for a critique of Arab political dependence on the United States.
RAPCAL code: A flexible package to compute radiative properties for optically thin and thick low and high-Z plasmas in a wide range of density and temperature
Authors: Rodríguez R. , Florido R. , Gil J.M. , Rubiano J.G. , Martel P. , Mínguez E.
Published: July 2008

Radiative properties are fundamental for plasma diagnostics and hydro-simulations. For this reason, there is a high interest in their determination and they are a current topic of investigation both in astrophysics and inertial fusion confinement research. In this work a flexible computation package for calculating radiative properties for low and high Z optically thin and thick plasmas, both under local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions, named RAPCAL is presented. This code has been developed with the aim of providing accurate radiative properties for low and medium Z plasmas within the context of detailed level accounting approach and for heavy elements under the detailed configuration accounting approach. In order to show the capabilities of the code, there are presented calculations of some radiative properties for carbon, aluminum, krypton and xenon plasmas under local thermodynamic and non-local thermodynamic equilibrium conditions.
Aspect‐related microclimatic influences on slope forms and processes, northeastern Arizona
Authors: Burnett Benjamin N. , Meyer Grant A. , McFadden Leslie D.
Published: July 2008

Climate is a major control on geomorphology, yet the effects of aspect‐related differences in microclimate have been little studied. We examined several 60–100‐m‐deep canyons in semiarid northeastern Arizona, where rock type and structure are essentially constant, but where field data and a high‐resolution digital elevation model reveal consistent morphologic and microclimatic differences between asymmetric north‐ and south‐facing sideslopes. Cliffs account for 29% of the vertical relief of south‐facing slopes but only 2.5% of north‐facing slopes. Excluding cliffs, south‐facing slopes are 1–3° steeper than north‐facing slopes and have significantly less weathered bedrock. We monitored air, surface and subsurface temperatures and soil moisture at 0.5‐h intervals at four locations over 1 year. South‐facing slopes were 1.4–5.6°C warmer and soil moisture tension at 10‐cm‐depth averages at least 78 kPa lower (drier) than on north‐facing slopes. The dominant rock type in the study area, Morrison formation sandstone, weathers primarily by clay hydration. These sandstones form disaggregated mantles where weathering exceeds erosion but also maintain steep slopes and cliffs where little weathered. South‐facing slopes were too dry during most of the instrumented year for significant clay expansion, whereas the north‐facing bedrock slope was moist all year. Cliff growth thus occurs preferentially on warmer and drier slopes, where weathering is reduced. Small north‐facing cliffs (typically <3 m) could have formed during the Holocene but cliffs up to 70 m high on southerly aspects require more time to form and likely persisted or expanded under cooler and wetter late Pleistocene climates.
Modeling energy dissipation and hydraulic jump regime responses to channel nonuniformity at river steps
Authors: Wyrick Joshua R. , Pasternack Gregory B.
Published: July 2008

The river step is an important driver for geomorphic evolution in bedrock rivers, but the effect that variations in channel geometry upstream and downstream of a river step have on hydraulic jump regime and energy dissipation has not previously been investigated. The associated hydraulic jump is inherent to a river step and its regime is a primary control on step morphodynamics. In turn, the hydraulic jump regime is controlled by several variables as detailed in a new conceptual framework herein. Also in this study, a parsimonious semianalytical numerical model of step hydraulics is developed to quantify energy dissipation and delineate hydraulic jump regimes, accounting for discharge, jump submergence, and nonuniform channel geometry through a step. Despite remaining limitations in step theory, the model simulates how natural steps respond to a wide range of conditions. The model shows that hydraulic jump regime and energy dissipation exhibit greater sensitivity to channel nonuniformity as discharge increases and/or step height decreases. Also, channel conditions that create greater jump submergence lead to decreased energy dissipation, regardless of the discharge regime. The model also reinforces the common observation about gully erosion that downstream channel widening enhances upstream knickpoint migration. The new algorithm may be used to aid river engineering involving steps and could be useful for landscape evolution modeling.
Coeval high‐pressure metamorphism, thrusting, strike‐slip, and extensional shearing in the Tauern Window, Eastern Alps
Authors: Glodny Johannes , Ring Uwe , Kühn Alexander
Published: July 2008

Recent findings for a young (31.5 ± 0.7 Ma) age of high‐pressure metamorphism at ∼90 km depths in the Eclogite Zone of the Tauern Window, Eastern Alps, prompt the question about the timing of the structural development of the Tauern Window and its relation to high‐pressure metamorphism. We show that all major structures in the Tauern Window, resulting from strong N‐S lithospheric shortening and simultaneous minor E‐W extension, began developing coevally with high‐pressure metamorphism in the Eclogite Zone. Large‐scale strike‐slip shear zones started to form at ∼32–30 Ma and facilitated the spatial accommodation of simultaneous shortening and extension. At least some of the strike‐slip and extensional shear zones operated into the Middle Miocene, either continuously or intermittently, with pronounced activity at ∼21–15 Ma. The considerable exhumation of the Eclogite Zone from ∼90 km depths into the middle crust, and the tectonic development of its framework occurred within only 1–2 Ma after eclogitization. This is evidenced by almost identical ages for eclogite facies metamorphism and for the development of the major structures that bound the Eclogite Zone under blueschist‐ and greenschist facies metamorphic conditions. We discuss a tectonic model in which considerable transpressional shortening and thickening took place in the present central‐southern part of the Tauern Window. We propose that the Tauern Window nucleated here and that most of the regional deformation at ∼32–30 Ma is today found at the periphery of the window and in the adjacent Austroalpine units. Afterward, transpression continued, the window grew to the E, W, and N, and deformation progressed to those parts of the window. Ductile deformation in the present‐day surface level ceased at ∼15 Ma.
Tuberculosis: a balanced diet of lipids and carbohydrates
Authors: Bhowruth Veemal , Alderwick Luke J. , Brown Alistair K. , Bhatt Apoorva , Besra Gurdyal S.
Published: July 2008

In spite of effective antibiotics to treat TB (tuberculosis) since the early 1960s, we enter the new millennium with TB currently the leading cause of death from a single infectious agent, killing more than 3 million people worldwide each year. Thus an understanding of drug-resistance mechanisms, the immunobiology of cell wall components to elucidate host–pathogen interactions and the discovery of new drug targets are now required for the treatment of TB. Above the plasma membrane is a classical chemotype IV peptidoglycan to which is attached the macromolecular structure, mycolyl-arabinogalactan via a unique diglycosylphosphoryl bridge. The present review discusses the assembly of the mAGP (mycolyl-arabinogalactan–peptidoglycan) complex and the site of action of EMB (ethambutol), bringing forward a new era in TB research and focus for new drugs to combat multidrug-resistant TB.
Interaction of the TFIIB zinc ribbon with RNA polymerase II
Authors: Elsby Laura M. , Roberts Stefan G.E.
Published: July 2008

Transcription by RNA polymerase II requires the assembly of the general transcription factors at the promoter to form a pre-initiation complex. The general transcription factor TF (transcription factor) IIB plays a central role in the assembly of the pre-initiation complex, providing a bridge between promoter-bound TFIID and RNA polymerase II/TFIIF. We have characterized a series of TFIIB mutants in their ability to support transcription and recruit RNA polymerase II to the promoter. Our analyses identify several residues within the TFIIB zinc ribbon that are required for RNA polymerase II assembly. Using the structural models of TFIIB, we describe the interface between the TFIIB zinc ribbon region and RNA polymerase II.
Switching genes on and off in haemopoiesis
Authors: Garrick David , De Gobbi Marco , Lynch Magnus , Higgs Douglas R.
Published: July 2008

At present, the molecular mechanisms by which stem cells commit to and differentiate towards specific lineages are poorly characterized, and will need to be better understood before stem cells can be exploited fully in experimental and clinical settings. Transcriptional regulation, the ability to turn genes on and off, lies at the heart of these processes of lineage commitment and specification. We have focused on fully understanding how these decisions are made at a single mammalian gene locus, the α-globin genes, which become up-regulated in a tissue- and developmental-stage specific manner during haemopoiesis. The studies summarized in the present article have revealed that complete regulation of this gene cluster involves not only activating mechanisms in expressing erythroid cells, but also repressing mechanisms, involving the Polycomb complex and histone deacetylases which are present in non-erythroid tissues. Taken together, these observations provide a well-characterized model of how gene expression is fully regulated during the transition from stem cells through lineage commitment and terminal differentiation.
The role of the Wilms' tumour-suppressor protein WT1 in apoptosis
Authors: Hartkamp Jörg , Roberts Stefan G.E.
Published: July 2008

The Wilms' tumour-suppressor gene (WT1), encodes a zinc-finger transcription factor that is critical for the development of several organs, including the kidneys, gonads and spleen. Despite its identification as a tumour suppressor that plays a crucial role in the formation of a paediatric malignancy of the kidneys (Wilms' tumour), it has also emerged as an oncogenic factor influencing proliferation and apoptosis in a large variety of adult cancers. This review focuses on new insights into WT1's role in early development and its potential oncogenic role in adult cancer.
The reversal of epigenetic silencing of the EBV genome is regulated by viral bZIP protein
Authors: Karlsson Questa H. , Schelcher Celine , Verrall Elizabeth , Petosa Carlo , Sinclair Alison J.
Published: July 2008

EBV (Epstein–Barr virus) alternates between latency and lytic replication. During latency, the viral genome is largely silenced by host-driven methylation of CpG motifs and in the switch to the lytic cycle this epigenetic silencing is overturned. A key event is the activation of the viral protein Zta with three ZREs (Zta-response elements) from the BRLF1 promoter (referred to as Rp). Two of these ZREs contain CpG motifs and are methylated in the latent genome. Biochemical analyses and molecular modelling of Zta bound to methylated RpZRE3 indicate the precise contacts made between a serine and a cysteine residue of Zta with methyl cytosines. A single point mutant of Zta, C189S, is defective in binding to the methylated ZREs both in vitro and in vivo. This was used to probe the functional relevance of the interaction. ZtaC189S was not able to activate Rp in a B-cell line, demonstrating the relevance of the interaction with methylated ZREs. This demonstrates that Zta plays a role in overturning the epigenetic control of viral latency.
Ribosomal acrobatics in post-transcriptional control
Authors: Gilbert Robert J.C. , Brierley Ian , McCarthy John E.G.
Published: July 2008

High-resolution structures have given an extremely detailed view of aspects of ribosomes, including some near-functional states. Here, we review the importance of cryo-electron microscopy, among other techniques, in giving an understanding of the higher dynamics of the ribosome accompanying active recruitment of mRNA to the small subunit and translocation of tRNAs. Recent data show that careful use of a variety of different techniques is necessary for a proper understanding of the basis of function in systems such as the ribosome.
Computational approaches to study transcriptional regulation
Authors: Babu M. Madan
Published: July 2008

In recent years, a number of technical and experimental advances have allowed us to obtain an unprecedented amount of information about living systems on a genomic scale. Although the complete genomes of many organisms are available due to the progress made in sequencing technology, the challenge to understand how the individual genes are regulated within the cell remains. Here, I provide an overview of current computational methods to investigate transcriptional regulation. I will first discuss how representing protein–DNA interactions as a network provides us with a conceptual framework to understand the organization of regulatory interactions in an organism. I will then describe methods to predict transcription factors and cis-regulatory elements using information such as sequence, structure and evolutionary conservation. Finally, I will discuss approaches to infer genome-scale transcriptional regulatory networks using experimentally characterized interactions from model organisms and by reverse-engineering regulatory interactions that makes use of gene expression data and genomewide location data. The methods summarized here can be exploited to discover previously uncharacterized transcriptional pathways in organisms whose genome sequence is known. In addition, such a framework and approach can be invaluable to investigate transcriptional regulation in complex microbial communities such as the human gut flora or populations of emerging pathogens. Apart from these medical applications, the concepts and methods discussed can be used to understand the combinatorial logic of transcriptional regulation and can be exploited in biotechnological applications, such as in synthetic biology experiments aimed at engineering regulatory circuits for various purposes.
The shock of the old: hydrodynamics for the masses
Authors: Scott David J.
Published: July 2008

Hydrodynamic techniques such as analytical ultracentrifugation can provide key information about subunit stoichiometry and interaction strengths of protein–nucleic acid interactions. Analysis is complicated by (i) the need for low concentrations in order to observe both free and bound species and (ii) thermodynamic non-ideality. With the introduction of fluorescence optics, we are able to obtain data at lower concentrations, and improved understanding of the statistical thermodynamics of macromolecular solutions has allowed non-ideality to be accurately assigned. With these developments, it is possible now to assay protein–nucleic acid interactions at concentrations typically used in molecular biology assays.
Practical Strategies: Nourishing Liquid Diet
Authors: Emley Sharon J. , Gluch Lynda , Casper Mary
Published: July 2008

The aging population is increasingly subject to dementia. All types and etiologies of dementia result in impaired memory, personality changes, and loss of cognitive function. Success with oral intake is often affected as dementia progresses. The individual with dementia may have issues with self-feeding, recognizing food, maintaining attention, persistence of action, or apraxia—all of which affect the ability to chew and swallow safely and effectively (Advisory Panel on Alzheimer's Disease, 1993). The patient's ability to maintain adequate nutritional status through eating by mouth may be lost as dementia progresses (Chouinard et al., 1998).

Caregivers and professionals may find themselves in a practical dilemma—how to provide nutritional intake and allow the patient to continue to eat by mouth safely and successfully while also overcoming the complicating factors present with dementia. In our organization, our dietitians developed an approach that offers a nutritional alternative to tube feeding—the nourishing liquid diet.
ASHA 2007 Zemlin Memorial Award Lecture: The Neural Control of Speech
Authors: Guenther Frank H.
Published: July 2008

Speech production involves coordinated processing in many regions of the brain. To better understand these processes, our research team has designed, tested, and refined a neural network model whose components correspond to brain regions involved in speech. Babbling and imitation phases are used to train neural mappings between phonological, articulatory, auditory, and somatosensory representations. After learning, the model can produce combinations of the sounds it has learned by commanding movements of an articulatory synthesizer. Computer simulations of the model account for a wide range of experimental findings, including data on acquisition of speaking skills, articulatory kinematics, and brain activity during speech. The model is also being used to investigate speech motor disorders, such as stuttering, apraxia of speech, and ataxic dysarthria. These projects compare the effects of damage to particular regions of the model to the kinematics, acoustics, or brain activation patterns of speakers with similar damage. Finally, insights from the model are being used to guide the design of a brain-computer interface for providing prosthetic speech to profoundly paralyzed individuals.
Management of Adults With Tracheostomy Across the Continuum of Care
Authors: Tippett Donna C.
Published: July 2008

In this article, intervention for adults with tracheostomy and ventilator dependency specific to acute inpatient, rehabilitation, and outpatient settings is described. During the acute hospitalization, restoration of communication is paramount. Candidacy for different communication options is explored. Patients and families are introduced to the role of the speech-language pathologist and begin to become informed about tracheostomy. Education is provided about the effects of tracheostomy on speaking, prognosis for improvement of speech, and the need for post acute therapy. The emphasis of speech-language pathology intervention in the post acute setting, particularly in the rehabilitation setting, is maximizing independence. Specific goals include restoring oral communication during all waking hours; refining ventilator-supported speech production; facilitating independence with cuff deflation/inflation; and fostering autonomous application and care of speaking valves. The goals of outpatient intervention are to promote carryover, monitor, and re-evaluate clinical status as needed and foster return to school and employment, resumption of recreational activities, and reintegration into home and family.
Bradykinin Degradation and Relation to Myocyte Contractility
Authors: Krombach R. Stephen , McElmuray James H. , Gay David M. , Clair Mark J. , Mukherjee Rupak , Goldberg Aron T. , Baicu Simona C. , Spinale Francis G.
Published: July 2008

Background: Past studies have demonstrated that exogenous bradykinin (BK) causes vasodilation and increases coronary blood flow, effects that may be beneficial in the setting of cardiac disease states. An important pathway for BK degradation is through angiotensin-converting enzyme (ACE), which results in the formation of a degradative peptide, BK(1-7). The goal of this study was to examine the effects of BK, BK(1-7), and the potential modulation of BK by ACE inhibition on myocyte contractility.

Methods and Results: Contractile function was examined in isolated adult porcine (n = 15) left ventricular (LV) myocyte preparations in the presence or absence of BK (10-8mol/L), BK(1-7)(10-8mol/L), and with pretreatment by ACE inhibition (benazaprilat). Myocyte velocity of shortening fell by over 15% in the presence of BK and by 8% with BK(1-7)( P < .05 vs basal). ACE inhibition blunted the negative effect of BK on myocyte velocity of shortening by over 60% ( P < .05). Furthermore, robust ACE activity coupled with significant BK degradation was demonstrated in LV-isolated myocyte preparations, and BK proteolysis was influenced by ACE inhibition.

Conclusion: These results suggest that BK has a direct effect on LV myocyte contractility, and that this effect may be mediated by proteolysis of BK at the level of the LV myocyte sarcolemma.
Effects of Lovastatin and Pravastatin on the Survival of Hamsters With Inherited Cardiomyopathy
Authors: März Winfried , Siekmeier Rüdiger , Müller Hans-Michael , Wieland Heinrich , Groß Werner , Olbrich Hans-Georg
Published: July 2008

Cardiomyopathic hamsters develop heart disease early in life, which leads to congestive heart failure and death as these hamsters age. Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been reported to reduce ubiquinone concentrations and to deteriorate myocardial function in humans and in experimental animals. HMG-CoA reductase inhibitors differ regarding their ability to penetrate extrahepatic tissues. As a consequence, lovastatin inhibits cholesterol biosynthesis at least 100-Fold more effectively than pravastatin in extrahepatic cells. We examined the effect of lovastatin and pravastatin (approximately 10 mg per kilogram of body weight and per day mixed in the diet) compared with controls on the lifespan of cardiomyopathic hamsters (BIO 8262 strain) in the heart-failure period. In male hamsters, neither lovastatin nor pravastatin significantly affected survival. In female hamsters, lovastatin reduced median survival time from 89 days (control animals) to 30 days ( P < .05); pravastatin (median survival, 115 days) had no statistically significant effect. We conclude that lovastatin, but not pravastatin, at a daily dose of 10 mg per kilogram of body weight significantly increases the mortality of cardiomyopathic hamsters. This effect may be the result of inhibition of myocardial ubiquinone supply.
Cost Analysis of Transthoracic Cardioversion of Atrial Fibrillation With and Without Ibutilide Pretreatment
Authors: Oral Hakan , Knight Bradley P. , Sticherling Christian , Kim Michael H. , Baker Robert L. , Chough Steven P. , Wasmer Kristina , Pelosi Frank , Michaud Gregory F. , Fendrick A. Mark , Adam Strickberger S. , Morady Fred
Published: July 2008

Background: Ibutilide may result in chemical cardioversion of atrial fibrillation and facilitates transthoracic cardioversion by lowering the defibrillation energy requirement. Whether routine pretreatment with ibutilide increases or decreases the cost of cardioversion is unknown. The purpose of this study was to compare the cost of outpatient transthoracic cardioversion of atrial fibrillation with and without ibutilide pretreatment.

Methods: Using a model based on published literature and hospital accounting information, a hypothetical group of 100 patients with atrial fibrillation and a left ventricular ejection fraction >0.30 underwent 2 strategies of outpatient cardioversion: transthoracic cardioversion with and without routine pretreatment with 1 mg ibutilide, and with and without involvement of an anesthesiologist for sedation. If transthoracic cardioversion was unsuccessful in patients who did not receive ibutilide, transthoracic cardioversion was repeated after administration of ibutilide.

Results: If an anesthesiologist was involved, transthoracic cardioversion with ibutilide was associated with incremental cost-savings as the efficacy of ibutilide alone in restoring sinus rhythm increased above the critical values of 20%, 27%, and 35% when the efficacy of transthoracic cardioversion alone was 60%, 80%, and 100%, respectively. In the absence of an anesthesiologist, routine pretreatment with ibutilide increased the cost of cardioversion at all success rates of transthoracic cardioversion.

Conclusions: In the presence of an anesthesiologist, whether or not routine pretreatment with ibutilide lowers the mean cost of cardioversion is determined by the success rates of chemical cardioversion with ibutilide and transthoracic cardioversion. In the absence of an anesthesiologist, ibutilide pretreatment increases the cost of cardioversion.
D-Ribose as a Supplement for Cardiac Energy Metabolism
Authors: Pauly Daniel F. , Pepine Carl J.
Published: July 2008

Metabolic support for the heart has been an attractive concept since the pioneering work of Sodi-Pallares et al. four decades ago.* Recently, interest has increased in the use of over-the-counter supplements and naturally occurring nutriceuticals for enhancement of cardiac and skeletal muscle performance. These include amino acids such as creatine, L-carnitine, and L-arginine, as well as vitamins and cofactors such as α-tocopherol and coenzyme Q. Like these other molecules. D-ribose is a naturally occurring compound. It is the sugar moiety of ATP and has also received interest as a metabolic supplement for the heart. The general hypothesis is that under certain pathologic cardiac conditions, nucleotides (particularly ATP, ADP, and AMP) are degraded and lost from the heart. The heart's ability to resynthesize ATP is then limited by the supply of D-ribose. which is a necessary component of the adenine nucleotide structure. In support of this hypothesis, recent reports have used D-ribose to increase tolerance to myocardial ischemia. Its use in patients with stable coronary artery disease improves time to exercise-induced angina and etectrocardiographic changes. In conjunction with thallium imaging or dobutamine stress echocardiography, D-ribose supplementation has been used to enhance detection of hibernating myocardium. In this article, we review the biochemical basis for using supplemental D-ribose as metabolic support for the heart and discuss the experimental evidence for its benefit.
Effects of Cilostazol on Heart Rate and its Variation in Patients With Atrial Fibrillation Associated With Bradycardia
Authors: Toyonaga Shinji , Nakatsu Takaaki , Murakami Takashi , Kusachi Shozo , Mashima Keiichi , Tominaga Youkou , Yamane Shinichi , Uesugi Tadahisa , Kanai Hideaki , Tsuji Takao
Published: July 2008

Background: Heart-rate (HR) variability is an important predictor of mortality in patients with heart disease. We examined the effects of cilostazol, a quinolinone derivative, on HR and HR variability in patients with chronic atrial fibrillation associated with bradycardia episodes.

Patients and Methods: Thirteen patients with chronic atrial fibrillation associated with bra dycardia episodes (minimal HR <40/min and/or pauses, ie, episodes with an RR interval > 2.5 sec) received cilostazol (100 or 200 mg/day) orally for at least 2 months and 24-hour Holter electrocardiography was performed before and after the start of cilostazol administration.

Results: Minimal HR was significantly increased, by an average of 14 beats/min (bpm), at 3.3 ± 0.8 weeks (mean ± SD) after the start of cilostazol treatment. The number of pauses was significantly decreased. As a consequence, mean HR was increased by an average of 18 bpm. Maximal HR was also increased by an average of 19 bpm. The circadian variation of the HR, determined by cosine fitting, was not changed by cilostazol treatment. The time-domain HR variabilities, ie, the SD of the mean RR interval and the SD of the 5-minute mean RR intervals, were also unchanged. New York Heart Association functional class was signifi cantly improved and the plasma atrial natriuretic polypeptide level was significantly de creased after the initiation of cilostazol treatment.

Conclusion: Cilostazol improves the slow HR episodes associated with chronic atrial fibril lation and maintains the HR circadian variation and time-domain variability, indicating that cilostazol has therapeutic utility for the treatment of the slow HR associated with chronic atrial fibrillation.
Magnetic properties of GaMnAs nanodot arrays fabricated using porous alumina templates
Authors: Bennett S. P. , Menon L. , Heiman D.
Published: July 2008

Ordered arrays of GaMnAs magnetic semiconductor nanodots have been fabricated using anodic porous alumina templates as etch masks. The magnetic behavior is studied for prepared arrays with 40 nm dot diameter, 15 nm dot thickness, and 80 nm periodicity. The disklike nanodots exhibit an easy axis for fields applied in the radial direction and a hard axis in the smaller direction. In the radial direction superparamagnetism is observed with a blocking temperature of 30 K. The fabrication technique is convenient for preparing nanodot arrays of compound semiconductors that cannot be formed by self-assembly techniques.
Electron backscatter diffraction mapping of herringbone domain structures in tetragonal piezoelectrics
Authors: Farooq M. U. , Villaurrutia R. , MacLaren I. , Burnett T. L. , Comyn T. P. , Bell A. J. , Kungl H. , Hoffmann M. J.
Published: July 2008

Herringbone domain structures have been mapped using electron backscatter diffraction in two tetragonal piezoelectrics: lead zirconate titanate [Pb(Zr,Ti)O3] and bismuth ferrite–lead titanate [(PbTi)0.5(BiFe)0.5O3]. Analysis of the domain misorientations across the band junctions shows that the structures correspond very well to crystallographic models. High resolution mapping with a 20nm step size allowed the crystal rotation across one of these band junctions in lead zirconate titanate to be studied in detail and allowed an improved estimation of the peak strain at the junction, of 0.56GPa. The significance of this for crack nucleation and propagation in such materials is discussed.
Turbulent inflow conditions for large-eddy simulation based on low-order empirical model
Authors: Perret Laurent , Delville Joël , Manceau Rémi , Bonnet Jean-Paul
Published: July 2008

Generation of turbulent inflow boundary conditions is performed by interfacing an experimental database acquired by particle image velocimetry to a computational code. The proposed method ensures that the velocity fields introduced as inlet conditions in the computational code present correct one- and two-point spatial statistics and a realistic temporal dynamics. This approach is based on the use of the proper orthogonal decomposition (POD) to interpolate and extrapolate the experimental data onto the numerical mesh and to model both the temporal dynamics and the spatial organization of the flow in the inlet section. Realistic representation of the flow is achieved by extracting and modeling independently its coherent and incoherent parts. A low-order dynamical model is derived from the experimental database in order to provide the temporal evolution of the most energetic structures. The incoherent motion is modeled by employing time series of Gaussian random numbers to mimic the temporal evolution of higher order POD modes. Validation of the proposed method is provided by performing a large-eddy simulation of a turbulent plane mixing layer, which is compared to experimental results.