bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of novel germanium‐containing poly(p‐phenylenevinylene) derivatives
Authors: Cho Hoon‐Je , Hwang Do‐Hoon , Lee Jong‐Don , Cho Nam‐Sung , Lee Sang‐Kyu , Lee Jonghee , Jung Young Kwan , Shim Hong‐Ku
Published: December 2007

Novel blue‐emitting germanium‐containing poly(p‐phenylenevinylene) (PPV) derivatives with well‐defined conjugation lengths were synthesized via Wittig‐condensation polymerizations. The polymers can be color‐tuned by the introduction of various chromophores into the PPV‐based polymer backbones. The photoluminescence (PL) spectra of the polymers, GePVK (containing carbazole moieties), GeMEH (containing dialkoxybenzene moieties), and GePTH (containing phenothiazine moieties), were found to exhibit blue, greenish blue, and green emissions, respectively. GePTH produces more red‐shifted emission than GeMEH and GEPVK, resulting in green emission, and the solution and solid state PL spectra of GePVK consist of almost blue emission. The electroluminescence spectra of GeMEH and GePTH contain yellowy green and yellow colors, respectively. Interestingly, GePVK exhibits white emission with CIE coordinates of (0.33, 0.37) due to electroplex emission in the light‐emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 979–988, 2008
Synthesis and characterization of highly fluorescent polythiophene derivatives containing polystyrene sidearms
Authors: Shen Jie , Tsuchiya Kousuke , Ogino Kenji
Published: December 2007

In this study, macroinitiators with different content of atom‐transfer radical polymerization (ATRP) functional group on polythiophene backbone were first prepared by the copolymerization of 3‐[1‐ethyl‐2‐(2‐bromopropionate)]thiophene and 3‐hexylthiophene with various feed ratio. Then poly [3‐hexyl‐2,5‐thienylene‐co‐3‐[1‐ ethyl‐2‐(2‐[poly(styrene)]propionate)]‐2,5‐thienylene] (PTTBr‐PS) with different graft density were obtained by ATRP of styrene from these macroinitiators in anisole. The degree of polymerization of PS sidearm (DPPS) was controlled by polymerization time. The structures of obtained graft copolymers were characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC). Introduction of the PS sidearms onto the backbone of polythiophene was an attempt to trap the polythiophene backbone in a “solution‐like” conformation, thus inhibit the packing of polythiophene backbone and result in the improvement of fluorescent property in solid state. This was verified by the UV–vis and fluorescence analyses. Besides, it was also found that the optical property of PTTBr‐PS graft copolymer was dominated by its graft density and independent on the degree of polymerization of its PS sidearm. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1003–1013, 2008
Insecticidal activity of menthol derivatives against mosquitoes
Authors: Samarasekera Radhika , Weerasinghe Indira S , Hemalal KD Patrick
Published: December 2007

BACKGROUND: The insecticidal activity of essential oil of Mentha piperita L. emend. Huds. against local mosquitoes as disease vectors was recognized and found to be due to the presence of menthol, which is the major aroma compound of the oil. The minor compounds of the oil, i.e. menthone, β‐caryophyllene, menthyl acetate, limonene, α‐pinene and pulegone, showed either less or no activity against the mosquitoes tested. L‐Menthol derivatives were synthesized and their knockdown effect and mortality were evaluated against local mosquitoes of Culex quinquefasciatus Say, Aedes aegypti L. and Anopheles tessellatus Theobald as disease vectors. This is the first report of mosquitocidal activity of menthol and its derivatives against Cx. quinquefasciatus, Ae. aegypti and An. tessellatus.

RESULTS: Derivative synthesis followed by structure–activity relationship studies identified several derivatives, i.e. menthyl chloroacetate, menthyl dichloroacetate, menthyl cinnamate, menthone glyceryl acetal, thymol, α‐terpineol and mugetanol, with enhanced mosquitocidal activity against Cx. quinquefasciatus, Ae. aegypti and An. tessellatus relative to the parent compound L‐menthone.

CONCLUSION: In ester derivatives of L‐menthol the optimum activity is dependent on the size and shape of the ester group and the presence of chlorine atoms in the ester group. In structurally related derivatives of L‐menthol the optimum activity is dependent on the aromaticity, the degree of unsaturation, the position of the hydroxy group and the type of functional group. Copyright © 2007 Society of Chemical Industry
On convex parameterization of robust control design for minimizing (conditional) performance at risk
Authors: Wang Qian
Published: December 2007

This paper introducesperformance at riskandconditional performance at riskas design metrics for the formulation of robust control design. These two metrics are used to characterize the high percentile or tail distribution of a performance specification when system uncertain parameters are random variables described by statistical distributions. The probabilistic robust control design is then formulated as a minimization problem with respect to the (conditional)performance at riskor as a constrained problem in terms of them. Performance specifications in terms of the high percentile or tail distribution are more stringent than that are defined in terms of the average (mean) value, which are often used in current literature for probabilistic robust control. Furthermore, the convexity of theconditional performance at riskdoes not have particular requirements on the underlying distribution of uncertain parameters; thus, convex optimization can be applied to the probabilistic robust control with respect to uncertain parameters with general distributions. The proposed probabilistic robust approach is applied to search solutions to linear matrix inequality containing random parametric uncertainties as well as to design a stabilizing controller for polynomial vector fields subject to random parametric uncertainties. Copyright © 2007 John Wiley & Sons, Ltd.
Historical Review of Surgical Simulation—A Personal Perspective
Authors: Satava Richard M.
Published: December 2007

Although simulation is relatively new to surgical education, there is a long history in many other disciplines, such as military, aviation, and nuclear power plant operations, among others. In the late 1980s these technologies began to be adapted to the surgical world, along with the new technology of virtual reality. This is a review of the introduction of manikins, computers, and virtual reality into education and training for surgical skills. Two concomitant revolutions occurred: objective assessment of surgical skills and converting training from the apprenticeship model to one of criterion‐based training. A personal perspective on these developments adds information not previously published.
NEONATAL MORTALITY IN THE EMPOWERED ACTION GROUP STATES OF INDIA: TRENDS AND DETERMINANTS
Authors: AROKIASAMY PERIANAYAGAM , GAUTAM ABHISHEK
Published: December 2007

In India, the eight socioeconomically backward states of Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Orissa, Rajasthan, Uttaranchal and Uttar Pradesh, referred to as the Empowered Action Group (EAG) states, lag behind in the demographic transition and have the highest infant mortality rates in the country. Neonatal mortality constitutes about 60% of the total infant mortality in India and is highest in the EAG states. This study assesses the levels and trends in neonatal mortality in the EAG states and examines the impact of bio-demographic compared with health care determinants on neonatal mortality. Data from India’s Sample Registration System (SRS) and National Family and Health Survey (NFHS-2, 1998–99) are used. Cox proportional hazard models are applied to estimate adjusted neonatal mortality rates by health care, bio-demographic and socioeconomic determinants. Variations in neonatal mortality by these determinants suggest that universal coverage of all pregnant women with full antenatal care, providing assistance at delivery and postnatal care including emergency care are critical inputs for achieving a reduction in neonatal mortality. Health interventions are also required that focus on curtailing the high risk of neonatal deaths arising from the mothers’ younger age at childbirth, low birth weight of children and higher order births with short birth intervals.
PATHWAYS INTO CHILDLESSNESS: EVIDENCE OF GENDERED LIFE COURSE DYNAMICS
Authors: KEIZER RENSKE , DYKSTRA PEARL A. , JANSEN MIRANDA D.
Published: December 2007

Using data from the first wave of the Netherlands Kinship Panel Study (NKPS) for 2867 women and 2195 men aged 40 to 79, this study examines to what extent educational, employment and marital pathways shape the likelihood of remaining childless, and whether these pathways are gendered. The findings indicate that women and men have distinctive pathways into childlessness. Educational attainment increases the likelihood of remaining childless among women only. A stable career increases the likelihood of remaining childless among women, but it increases the likelihood of entering fatherhood. Years without a partner is positively associated with childlessness among both women and men. Not having had a partnership and having had multiple partnerships are strong determinants of childlessness, especially among men.
OBJECTIVISM AND RELATIONAL GOOD
Authors: Rosati Connie S.
Published: December 2007

In his critique of egoism as a doctrine of ends, G. E. Moore famously challenges the idea that something can be “good for” someone. Donald Regan has recently revived and developed the Moorean challenge, making explicit its implications for the very idea of individual welfare. If the Moorean is right, there is no distinct, normative propertygood for, and so no plausible objectivism about ethics could be welfarist. In this essay, I undertake to address the Moorean challenge, clarifying our theoretical alternatives so that we may better decide what to admit into our moral ontology and better assess what may be at stake in whether objectivists treatgoodorgood for(or neither) as fundamental. I compare the Moorean and welfarist pictures of value, providing an account of the form and function ofgood for. According to this account “good for” expresses a distinctrelational valuethat has its source in the value of persons. Good for value is thus a form of extrinsic value that provides agent-neutral reasons for action, and it plays a pervasive normative role in regulating child rearing, guiding individual life choices, and shaping social policy formation.
Temporal resolution and temporal transfer properties: Gabaergic and cholinergic mechanisms
Authors: BEHREND KONSTANTIN , BENKNER BORIS , MORA-FERRER CARLOS
Published: December 2007

Temporal resolution is a basic property of the visual system and critically depends upon retinal temporal coding properties which are also of importance for directional coding. Whether the temporal coding properties for directional coding derive form inherent properties or critically depend upon the temporal coding mechanisms is unclear. Here, the influence of acetylcholine and GABA upon photopic temporal coding was investigated in goldfish, using flicker stimuli, in a behavioral and an electrophysiological (ERG) approach. The goldfish temporal resolution ability decreased from more than 90% correct choices at 20 Hz flicker frequency to about 65% at 45 Hz flicker frequency with a flicker fusion frequency of approximately 39 Hz. Blockade of GABAa-receptors reduced the flicker fusion frequency to about 23 Hz, not affecting temporal resolution below 20 Hz flicker frequency. Partial blockade of nicotinic acetylcholine receptors reduced the flicker fusion frequency slightly and lowered the temporal resolution ability in the 25–30 Hz range. Blockade of muscarinic acetylcholine receptors had a smaller effect than the partial blockade of nicotinic acetylcholine receptors. In ERG-recordings, blocking GABAa-receptors increased the a- and b-wave amplitude, induced a delay, an increase and a slow fall-off of the d-wave. Blocking GABAc-receptors had little effect. Blocking GABAa- or GABAa/c-receptors changed the temporal resolution, when expressed as a linear filter, from a 3rd degree filter with resonance to a low order low-pass filter with a low upper limit frequency. The temporal transfer properties were barely changed by blocking either nicotinic or muscarinic acteylcholine receptors, although ERG-components increased in amplitude to varying degrees. The behavioral and electrophysiological data indicate the important role of GABA for temporal processing but little involvement of the cholinergic system. It is proposed that the interaction of the GABAergic amacrine cell network and bipolar cells determines the gain of the retinal temporal coding in the upper frequency range.
Eine sozialpsychologische Analyse zur Reduzierung sozialer Diskriminierung von Menschen mit Migrationshintergrund
Authors: Sassenberg Kai , Fehr Jennifer , Hansen Nina , Matschke Christina , Woltin Karl-Andrew
Published: December 2007

Zusammenfassung: Migration hat die deutsche Gesellschaft verändert. In jüngster Zeit wird dies auch auf politischer Ebene verstärkt diskutiert. Wenngleich die Integration von Menschen mit Migrationshintergrund angestrebt wird, so sind sie dennoch häufig sozialer Diskriminierung ausgesetzt, die einer erfolgreichen Integration entgegensteht. Ausgehend vom sozial-kognitiven Ansatz und dem Ansatz der sozialen Identität gibt der vorliegende Beitrag einen Überblick zum Stand der Forschung bezüglich der Faktoren, die zu sozialer Diskriminierung beitragen bzw. ihr entgegenwirken. Dieser Überblick dient in Folge als Grundlage für die Ableitung von Empfehlungen bezüglich der Gestaltung politischer und gesellschaftlicher Prozesse mit dem Ziel, durch die Reduzierung sozialer Diskriminierung einen Beitrag zur erfolgreichen gesellschaftlichen Integration von Menschen mit Migrationshintergrund zu leisten. Die resultierenden Empfehlungen werden abschließend integriert und diskutiert. Die Praxisrelevanz, aber auch die diesbezüglichen Grenzen sozialpsychologischer Forschung werden ebenfalls dargestellt.
Die Messung von Werten mit dem “Portraits Value Questionnaire”
Authors: Schmidt Peter , Bamberg Sebastian , Davidov Eldad , Herrmann Johannes , Schwartz Shalom H.
Published: December 2007

Zusammenfassung: In zwei Stichproben wird eine deutschsprachige 40-Item Version des “Portraits Value Questionnaire” (PVQ) validiert; in einer dritten Stichprobe (European Social Survey) wird eine verkürzte Version mit 21 Items dieses Werteinventars validiert. Bei dem PVQ handelt es sich um ein von Shalom Schwartz neu entwickeltes Instrument zur Überprüfung seiner Theorie grundlegender menschlicher Werte. Die Aufgabenstellung des PVQ unterscheidet sich konzeptionell deutlich von der des bisher verwendeten Standardinstrumentes “Schwartz Value Survey” (SVS). Das neue Instrument ist besonders für Probanden mit mittlerer und niedriger Schulbildung geeignet. Unsere Ergebnisse belegen die instrumentenunabhängige Validität der von Schwartz postulierten Wertetheorie. Der Vergleich mit dem SVS belegt die konvergente und diskriminante Validität der mit dem PVQ gemessenen zehn Wertetypen. Auch die vorhergesagten Beziehungen der Wertetypen mit zwei externen Konstrukten belegen die Konstruktvalidität des PVQ. In einer konfirmatorischen Faktorenanalyse wird die postulierte Zahl der unterschiedlichen Werte nicht bestätigt, da neun statt zehn Werte als empirisch angemessen erscheinen. Eine externe Validierung mit den Daten des repräsentativen European Social Survey in Deutschland durch eine konfirmatorische Faktorenanalyse (jedoch nur mit 21 Items) hat die Schwartz'sche Werteskala weitgehend bestätigt, allerdings mussten sechs der zehn Wertetypen zu dreien zusammengefasst werden.
Dynamics and deposits generated by the Kos Plateau Tuff eruption: Controls of basal particle loss on pyroclastic flow transport
Authors: Dufek Josef , Bergantz George W.
Published: December 2007

The explosive eruption of voluminous silicic magmas often produces widespread and massive deposits formed from pyroclastic density currents. While these punctuated events dramatically alter the landscape and have potential climate‐altering impact, our understanding of the internal structure and transport dynamics of these eruptions is hampered by a lack of direct observations. We utilize the natural boundary conditions encountered by the eruption of the Kos Plateau Tuff to probe its internal structure as well as constrain the neotectonic activity in the region and eruption duration of this moderate to large (>60 km3) event. At the time of the eruption, 161 ka, the lower sea level in the Mediterranean may have resulted in flows that traversed mostly land to the north of the eruptive vent, while flows to the south may have encountered an expanse of water. Steep topography and overwater transport can impede the transport of the dense basal portions of the flow where particles make multiple or sustained contact with the bed. We use an Eulerian‐Eulerian‐Lagrangian computational approach coupled with overwater and overland boundary conditions, including topography, to determine the role of bed load versus suspended load in the transport of these flows. We find that a ring vent structure and eruptive fluxes greater than ∼2 × 106 m3/s are required for the spatial distribution of the KPT. The maximum grain size and deposit locations of the first voluminous ignimbrite unit (D) can be explained by suspended flow to the south, consistent with overwater transport, and bed load and suspended load transport to the north, consistent with overland transport. However, the maximum lithic size for the largest and last ignimbrite unit (E) requires some bed load transport in all directions. We propose that the boundary conditions were significantly altered during the course of the eruption, through either the in‐filling of a shallow sea to the south or the development of a thick pumice raft to aid saltation. On the basis of the inferred eruptive flux, we estimate that the duration of the eruption climax, in which most of the material was erupted, likely only lasted from a few hours to a day.
A Study of the Survival Factors of Free Flap in Older Diabetic Patients
Authors: Lee Yoon Jung , Kim J.-Young
Published: December 2007

We investigated the reconstruction of feet in older diabetic patients, assessing the factors that affect the survival of transplantation tissue and successful transplantation with a prospective survey. From October 2004 to December 2005, the patients, who underwent reconstruction of diabetic feet with an anterolateral thigh perforator free flap, were all over 55 years old at the time of operation. We performed hematologic, hemodynamic, diabetic, bacteriologic, and radiological tests prior to the surgery, evaluating the condition of blood vessels at the donor site and the recipient site and the condition of transplantation tissues. After the surgery, we determined the survival or death of transplantation tissue. Fifteen of 16 patients were evaluated. In one case, transplantation failed, and in four cases, partial graft tissue-necrosis occurred. All assayed terms of the patients and the chart were similar except for peak blood flow velocity (PBFV), which was measured by Doppler ultrasonography at the artery recipient site. The PBFV in failed patients was 20 cm/s. In cases of delayed wound-healing, the PBFV was 30 cm/s. All patients with PBFVs over 40 cm/s had successful results. So using free flap transplantation to remedy diabetic foot ulcers can produce excellent or good results, especially in patients with PBFVs over 40 cm/s at the recipient artery.
A Framework for Visualization and Exploration of Events
Authors: Beard Kate , Deese Heather , Pettigrew Neal R.
Published: December 2007

The expanding deployment of sensor systems that capture location, time, and multiple thematic variables is increasing the need for exploratory spatio-temporal data analysis tools. Geographic information systems (GIS) and time series analysis tools support exploration of spatial and temporal patterns respectively and independently, but tools for the exploration of both dimensions within a single system are relatively rare. The contribution of this research is a framework for the visualization and exploration of spatial, temporal, and thematic dimensions of sensor-based data. The unit of analysis is an event, a spatio-temporal data type extracted from sensor data. The conceptual framework suggests an approach for design layout that can be flexibly modified to explore spatial and temporal trends, temporal relationships among events, periodic temporal patterns, the timing of irregularly repeating events, event–event relationships in terms of thematic attributes, and event patterns at different spatial and temporal granularities. Flexible assignment of spatial, temporal, and thematic categories to a set of graphical interface elements that can be easily rearranged provides exploratory power as well as a generalizable design layout structure. The framework is illustrated with events extracted from Gulf of Maine Ocean Observing System data but the approach has broad application to other domains and applications in which time, space, and attributes need to be considered in conjunction.
Transmembrane domains of the syndecan family of growth factor coreceptors display a hierarchy of homotypic and heterotypic interactions
Authors: Dews Ian C. , MacKenzie Kevin R.
Published: December 2007

The single-pass transmembrane domains (TMDs) of the syndecan family of cell surface adhesion molecules have been implicated in functional protein–protein interactions. Although each paralog contains a conserved GxxxG dimerization motif, we show here that the syndecan-1 TMD dimerizes weakly, the syndecan-3 and syndecan-4 TMDs each dimerize strongly, and the syndecan-2 TMD dimerizes very strongly. These markedly different levels of self-association suggest that paralog TMDs play different roles in directing functional interactions of each full-length syndecan family member. We further show that each syndecan TMD forms detergent-resistant heteromeric complexes with other paralogs, and that these interactions exhibit selectivity. Although heteromeric interactions among full-length syndecan paralogs have not been reported, we argue that the distinct hierarchy of protein–protein interactions mediated by the syndecan TMDs may give rise to considerable complexity in syndecan function. The demonstration that TMD homodimerization and heterodimerization can be mediated by GxxxG motifs and modulated by sequence context has implications for the signaling mechanisms of other cell surface receptors, including the integrins and the erbB family.
The Poverty of Transition: From Industrial District to Poor Neighbourhood in the City of Nanjing, China
Authors: Fulong Wu
Published: December 2007

This paper aims to understand the formation of poor neighbourhoods through examining the transformation of a suburban industrial district into a poverty neighbourhood in the city of Nanjing. The notion of a poverty of transition is developed to show how such a transformation occurs in the aftermath of state-led industrialisation. It is argued that, rather than simply being attributable to marketisation, the driving-forces include a set of institutional changes that work together to pave the way for the development of poor neighbourhoods: deindustrialisation drives industrial workers and the self-employed at the margin into a poverty trap; self-exploited and hardworking rural migrants, not covered by official welfare support, are becoming the working poor; housing privatisation serves to convert low-income households into homeowners of low-capitalised assets; the new minimum living standard regime contains the poor and maintains the stability of poverty neighbourhoods.
Emergent Local Initiative and the City: The Case of Neighbourhood Associations of the Better-off Classes in Post-1990 Urban Turkey
Authors: Erman Tahire , Coşkun-Yιldar Meliha
Published: December 2007

This article investigates the voluntary local organisations of the better-off classes in the Turkish urban context. Based on empirical research conducted with four neighbourhood associations (NAs), information is provided regarding their process of establishment, leadership, autonomy, goals and projects, resources and obstacles, which points to the significance of context. The research demonstrates that Turkish NAs differ from those in the West in terms of their commitment to ideological as much as pragmatic issues. In their response to the 'Islamist' versus 'secularist' polarisation in society, they seek to create their own localities as the places of secular and cosmopolitan people; and in their response to the increasingly unregulated and poorly serviced city, they struggle to create orderly localities protected from unlawful rent-seeking practices and equipped with adequate amenities. The NAs may be regarded as civic initiatives that empower the locality. Yet, by doing so, they may cause uneven development in urban space.
Urbanisation, Urban Concentration and Economic Development
Authors: Bertinelli Luisito , Strobl Eric
Published: December 2007

The paper investigates how urban primacy affects economic growth across countries. Using semi-parametric estimation techniques on a cross-country panel for the years 1960—90, an increasing relationship is unearthed between urban primacy and growth. This result holds even when limiting the sample to the developing country group, thus moderating previous findings on the existence of an optimal level of urban primacy, by suggesting that if such an optimal level exists, the range of values of urban primacy for which it is reached is fairly wide.
A Novel Site of Action for α-SNAP in the SNARE Conformational Cycle Controlling Membrane Fusion
Authors: Barszczewski Marcin , Chua John J. , Stein Alexander , Winter Ulrike , Heintzmann Rainer , Zilly Felipe E. , Fasshauer Dirk , Lang Thorsten , Jahn Reinhard
Published: December 2007

Regulated exocytosis in neurons and neuroendocrine cells requires the formation of a stable soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex consisting of synaptobrevin-2/vesicle-associated membrane protein 2, synaptosome-associated protein of 25 kDa (SNAP-25), and syntaxin 1. This complex is subsequently disassembled by the concerted action of α-SNAP and the ATPases associated with different cellular activities-ATPase N-ethylmaleimide-sensitive factor (NSF). We report that NSF inhibition causes accumulation of α-SNAP in clusters on plasma membranes. Clustering is mediated by the binding of α-SNAP to uncomplexed syntaxin, because cleavage of syntaxin with botulinum neurotoxin C1 or competition by using antibodies against syntaxin SNARE motif abolishes clustering. Binding of α-SNAP potently inhibits Ca2+-dependent exocytosis of secretory granules and SNARE-mediated liposome fusion. Membrane clustering and inhibition of both exocytosis and liposome fusion are counteracted by NSF but not when an α-SNAP mutant defective in NSF activation is used. We conclude that α-SNAP inhibits exocytosis by binding to the syntaxin SNARE motif and in turn prevents SNARE assembly, revealing an unexpected site of action for α-SNAP in the SNARE cycle that drives exocytotic membrane fusion.
Ballistic dispersion in temperature gradient focusing
Authors: Huber David E , Santiago Juan G
Published: December 2007

Molecular dispersion is caused by both molecular diffusion and non-uniform bulk fluid motion. While the Taylor–Aris dispersion regime is the most familiar regime in microfluidic systems, an oft-overlooked regime is that of purely kinematic (or ballistic) dispersion. In most microfluidic systems, this dispersion regime is transient and quickly gives way to Taylor–Aris dispersion. In electrophoretic focusing methods such as temperature gradient focusing (TGF), however, the characteristic time scales for dispersion are fixed, and focused peaks may never reach the Taylor limit. In this situation, generalized Taylor dispersion analysis is not applicable. A heuristic model is developed here which accounts for both molecular diffusion and advective dispersion across all dispersion regimes, from pure diffusion to Taylor dispersion to pure advection. This model is compared to results from TGF experiments and accurately captures both the initial decrease and subsequent increase in peak widths as electric field strength increases. The results of this combined analytical and experimental study provide a useful tool for estimation of dispersion and optimization of TGF systems.
Adaptive developmental plasticity in growing nestlings: sibling competition induces differential gape growth
Authors: Gil Diego , Bulmer Elena , Celis Patricia , López-Rull Isabel
Published: December 2007

Sibling competition has been shown to affect overall growth rates in birds. However, growth consists on the coordinated development of a multitude of structures, and there is ample scope for developmental plasticity and trade-offs among these structures. We would expect that the growth of structures that are used in sibling competition, such as the gape of altricial nestlings, should be prioritized under intense competition. We conducted an experiment in the spotless starling (Sturnus unicolor), cross-fostering nestlings to nests with different levels of sibling competition. We predicted that nestlings subjected to higher levels of sibling competition should develop larger gapes than control birds. We found that, halfway through the nestling period, overall size (a composite index of mass, wing, tarsus and bill) was reduced in nests with intense sibling competition, whereas gape width remained unaffected. At the end of the nestling period, experimental nestlings had wider gapes than controls. Additionally, a correlative study showed that nestling gape width increased when feeding conditions worsened and overall size decreased. These patterns could either be due to increased growth of gape flanges or to delayed reabsorption of this structure. Our results show that birds can invest differentially in the development of organs during growth, and that the growth of organs used in sibling competition is prioritized over structural growth.
Running, swimming and diving modifies neuroprotecting globins in the mammalian brain
Authors: Williams Terrie M , Zavanelli Mary , Miller Melissa A , Goldbeck Robert A , Morledge Michael , Casper Dave , Pabst D. Ann , McLellan William , Cantin Lucas P , Kliger David S
Published: December 2007

The vulnerability of the human brain to injury following just a few minutes of oxygen deprivation with submergence contrasts markedly with diving mammals, such as Weddell seals (Leptonychotes weddellii), which can remain underwater for more than 90 min while exhibiting no neurological or behavioural impairment. This response occurs despite exposure to blood oxygen levels concomitant with human unconsciousness. To determine whether such aquatic lifestyles result in unique adaptations for avoiding ischaemic–hypoxic neural damage, we measured the presence of circulating (haemoglobin) and resident (neuroglobin and cytoglobin) oxygen-carrying globins in the cerebral cortex of 16 mammalian species considered terrestrial, swimming or diving specialists. Here we report a striking difference in globin levels depending on activity lifestyle. A nearly 9.5-fold range in haemoglobin concentration (0.17–1.62 g Hb 100 g brain wet wt−1) occurred between terrestrial and deep-diving mammals; a threefold range in resident globins was evident between terrestrial and swimming specialists. Together, these two globin groups provide complementary mechanisms for facilitating oxygen transfer into neural tissues and the potential for protection against reactive oxygen and nitrogen groups. This enables marine mammals to maintain sensory and locomotor neural functions during prolonged submergence, and suggests new avenues for averting oxygen-mediated neural injury in the mammalian brain.
Implementation of Periodicity Ratio in Analyzing Nonlinear Dynamic Systems: A Comparison With Lyapunov Exponent
Authors: Dai Liming , Wang Guoqing
Published: December 2007

The present research intends to investigate the characteristics of the periodicity ratio and its implementation in analyzing the nonlinear behavior of dynamic systems governed by second-order differential equations. Numerical analyses on the nonlinear dynamic systems with employment of the periodicity ratio for diagnosing chaotic, regular, and irregular behaviors of dynamic systems are performed. To characterize the approach with periodicity ratio in distinguishing different behaviors of the nonlinear dynamic systems, a comparison of periodicity ratio with the widely used Lyapunov exponent in numerically assessing the responses of nonlinear dynamic systems is presented.
Differentiation of C2D Macrophage Cells after Adoptive Transfer
Authors: Potts Betsey E. , Hart Marcia L. , Snyder Laura L. , Boyle Dan , Mosier Derek A. , Chapes Stephen K.
Published: December 2007

C2D macrophage cells protect immunocompromised mice from experimentally induced pneumonias after intraperitoneal (i.p.) adoptive transfer. These macrophage cells are immature and display minimal activity in vitro. Therefore, we wanted to understand how adoptive transfer affected these cells. We believe that the in vivo environment affects the phenotypic and functional characteristics of macrophages that help maintain the physiological integrity of the host. To test this hypothesis, we characterized the trafficking patterns and cellular changes of the established macrophage C2D cell line after adoptive transfer. We examined phenotypic changes of the C2D macrophage cells in vivo with and without stimulation with gamma interferon (IFN-γ). After in vivo i.p. adoptive transfer, C2D macrophage cells trafficked to the lungs, spleen, lymph nodes, and bone marrow of recipient mice. The cells were detected for as long as 2 months, and the cells expressed increased levels of CD11b, c-fms, and F4/80 on their surface, becoming more differentiated macrophages compared to cells maintained in vitro. Upon in vivo stimulation with IFN-γ, c-fms levels decreased while Gr-1 levels increased compared to in vivo, unstimulated, phosphate-buffered saline-injected controls. These responses were independent of the genetic backgrounds of the recipient mice. These data support the hypothesis and indicate that C2D macrophage cells respond to in vivo signals that are absent during in vitro culture.
Sequential Analysis of
Anaplasma phagocytophilum msp2
Transcription in Murine and Equine Models of Human Granulocytic Anaplasmosis
Authors: Scorpio Diana G. , Leutenegger Christian , Berger Jeannine , Barat Nicole , Madigan John E. , Dumler J. Stephen
Published: December 2007

Anaplasma phagocytophilum
causes human granulocytic anaplasmosis by inducing immunopathologic responses. Its immunodominant Msp2 protein is encoded by a family of >100 paralogs. Msp2 (
msp2
) expression modulates in the absence of immune pressure, and prolonged in vitro passage modulates in vivo virulence. Because programmed MSP2 expression occurs in
Anaplasma marginale
, we hypothesized a similar event in
A. phagocytophilum
in vivo, with specific Msp2 expression triggering immunopathologic injury or clinical manifestations of disease. We examined
msp2
transcripts in 11 B6 mice and 6 horses inoculated with low- or high-passage
A. phagocytophilum
Webster strain. Blood was sequentially obtained through 3 weeks postinfection for
msp2
reverse transcription-PCR. Horses were additionally assessed for clinical manifestations, seroconversion, complete blood count, blood chemistry, and cytokine gene transcription. In both species, there was no consistent emergence of
msp2
transcripts, and all 22
msp2
variants were detected in both passage groups. Clinical severity was much higher for high-passage-infected than for low-passage-infected horses, preceded by higher levels of blood gamma interferon transcription on day 7. Antibody was first detected on day 7, and all horses seroconverted by day 22, with a trend toward lower antibody titers in low-passage-infected animals. Leukocyte and platelet counts were similar between experimental groups except on day 13, when low-passage-infected animals had more profound thrombocytopenia. These findings corroborate studies with mice, where
msp2
diversity did not explain differences in hepatic histopathology, but differ from the paradigm of low-passage
A. phagocytophilum
causing more significant clinical illness. Alteration in transcription of
msp2
has no bearing on clinical disease in horses, suggesting the existence of a separate proinflammatory component differentially expressed with changing in vitro passage.
Distribution of Conjugative-Plasmid-Mediated 16S rRNA Methylase Genes among Amikacin-Resistant
Enterobacteriaceae
Isolates Collected in 1995 to 1998 and 2001 to 2006 at a University Hospital in South Korea and Identification of Conjugative Plasmids Mediating Dissemination of 16S rRNA Methylase
Authors: Kang Hee Young , Kim Ki Young , Kim Jungmin , Lee Je Chul , Lee Yoo Chul , Cho Dong Taek , Seol Sung Yong
Published: December 2007

The distribution of conjugative-plasmid-mediated 16S rRNA methylase genes among amikacin-resistant
Enterobacteriaceae
collected between 1995 and 1998 and between 2001 and 2006 at a university hospital in South Korea was examined, and conjugative plasmids carrying the 16S rRNA methylase genes were characterized by PCR-based replicon typing and by determination of their antimicrobial resistance pattern. Among the 7,127 isolates, 463 isolates showed a high level of resistance to amikacin, and 218 of the 463 isolates transferred amikacin resistance by conjugation. Among the 218 isolates,
armA
was detected in 153 isolates (88
Klebsiella pneumoniae
, 28
Escherichia coli
, 19
Enterobacter cloacae
, and 6
Serratia marcescens
isolates and 12 isolates of other organisms), and
rmtB
was detected in 51 isolates (32
K. pneumoniae
isolates, 18
E. coli
isolates, and 1
Citrobacter freundii
isolate). The first appearance of
armA
was in 1997. The
armA
gene was carried by conjugative plasmids of replicon groups IncL/M, IncFIIAs, IncF, IncA/C, IncHI2, and Inc(unidentified) in 38, 20, 7, 9, 4, and 75 strains, respectively. The
rmtB
gene was carried by conjugative plasmids of groups IncA/C, IncF, and IncI1-Iγ in 43 strains, 7 strains, and 1 strain, respectively. Transconjugants that received the IncL/M plasmid carrying
armA
or the IncA/C plasmid carrying
rmtB
showed an additional resistance to cefotaxime. Transconjugants that received the IncFIIA plasmid or Inc(unidentified) plasmid carrying the
armA
gene showed an additional resistance to cefoxitin and a high MIC
50
(0.25 mg/liter) of ciprofloxacin. In conclusion, this study demonstrated that the dissemination of 16S rRNA methylase genes among the
Enterobacteriaceae
is mediated by conjugative plasmids of various incompatibility groups that confer resistance to multiple drugs, including aminoglycosides, extended-spectrum β-lactams, and/or quinolones.
Multiplex PCR That Can Distinguish between Immunologically Cross- Reactive Serovar 3, 6, and 8Actinobacillus pleuropneumoniaeStrains
Authors: Zhou L. , Jones S. C. P. , Angen Ø. , Bossé J. T. , Nash J. H. E. , Frey J. , Zhou R. , Chen H. C. , Kroll J. S. , Rycroft A. N. , Langford P. R.
Published: December 2007

We describe a highly sensitive and specific multiplex PCR, based on capsular loci and the species specificapxIVgene, that unequivocally differentiates serovar 3, 6, and 8Actinobacillus pleuropneumoniaestrains that are cross-reactive in conventional immunological tests.
Virus-Specific T-Cell Immunity Correlates with Control of GB Virus B Infection in Marmosets
Authors: Woollard David J. , Haqshenas Gholamreza , Dong Xuebin , Pratt Bridget F. , Kent Stephen J. , Gowans Eric J.
Published: December 2007

GB virus B (GBV-B) is a hepatotropic virus that is closely related to hepatitis C virus (HCV). GBV-B causes acute hepatitis in infected marmosets and tamarins and is therefore a useful small-animal model for the study of HCV. We investigated virus-specific T-cell responses in marmosets infected with GBV-B. Gamma interferon (IFN-γ) enzyme-linked immunospot (ELISPOT) assay responses in the peripheral blood of two marmosets were assessed throughout the course of GBV-B infection. These T-cell responses were directed against the GBV-B nonstructural proteins 3 (NS3), 4A (NS4A), and 5B (NS5B), and their appearance was temporally associated with clearance of viremia. These marmosets were then rechallenged with GBV-B at least 3 months after clearance of the primary infection to determine if the animals were protected from reinfection. There was no detectable viremia following reinfection, although a sharp increase in T-cell responses against GBV-B proteins was observed. Epitope mapping of T-cell responses to GBV-B was performed with liver and blood samples from both marmosets after rechallenge with GBV-B. Three shared, immunodominant T-cell epitopes within NS3 were identified in animals with multiple common major histocompatibility complex class I alleles. IFN-γ ELISPOT responses were also detected in the livers of two marmosets that had resolved a primary GBV-B infection. These responses were high in frequency and were directed against epitopes within GBV-B NS3, NS4A, and NS5B proteins. These results indicate that virus-specific T-cell responses are detectable in the liver and blood of GBV-B-infected marmosets and that the clearance of GBV-B is associated with the appearance of these responses.
CD4 T Cells Contribute to Virus Control and Pathology following Central Nervous System Infection with Neurotropic Mouse Hepatitis Virus
Authors: Stohlman Stephen A. , Hinton David R. , Parra Beatriz , Atkinson Roscoe , Bergmann Cornelia C.
Published: December 2007

Replication of the neurotropic mouse hepatitis virus strain JHM (JHMV) is controlled primarily by CD8+T-cell effectors utilizing gamma interferon (IFN-γ) and perforin-mediated cytotoxicity. CD4+T cells provide an auxiliary function(s) for CD8+T-cell survival; however, their direct contribution to control of virus replication and pathology is unclear. To examine a direct role of CD4+T cells in viral clearance and pathology, pathogenesis was compared in mice deficient in both perforin and IFN-γ that were selectively reconstituted for these functions via transfer of virus-specific memory CD4+T cells. CD4+T cells from immunized wild-type, perforin-deficient, and IFN-γ-deficient donors all initially reduced virus replication. However, prolonged viral control by IFN-γ-competent donors suggested that IFN-γ is important for sustained virus control. Local release of IFN-γ was evident by up-regulation of class II molecules on microglia in recipients of IFN-γ producing CD4+T cells. CD4+T-cell-mediated antiviral activity correlated with diminished clinical symptoms, pathology, and demyelination. Both wild-type donor CD90.1 and recipient CD90.2 CD4+T cells trafficked into the central nervous system (CNS) parenchyma and localized to infected white matter, correlating with decreased numbers of virus-infected oligodendrocytes in the CNS. These data support a direct, if limited, antiviral role for CD4+T cells early during acute JHMV encephalomyelitis. Although the antiviral effector mechanism is initially independent of IFN-γ secretion, sustained control of CNS virus replication by CD4+T cells requires IFN-γ.
Ty3 Nucleocapsid Controls Localization of Particle Assembly
Authors: Larsen Liza S. Z. , Beliakova-Bethell Nadejda , Bilanchone Virginia , Zhang Min , Lamsa Anne , DaSilva Rhonda , Hatfield G. Wesley , Nagashima Kunio , Sandmeyer Suzanne
Published: December 2007

Expression of the budding yeast retrotransposon Ty3 results in production of viruslike particles (VLPs) and retrotransposition. The Ty3 major structural protein, Gag3, similar to retrovirus Gag, is processed into capsid, spacer, and nucleocapsid (NC) during VLP maturation. The 57-amino-acid Ty3 NC protein has 17 basic amino acids and contains one copy of the CX
2
CX
4
HX
4
C zinc-binding motif found in retrovirus NC proteins. Ty3 RNA, protein, and VLPs accumulate in clusters associated with RNA processing bodies (P bodies). This study investigated the role of the NC domain in Ty3-P body clustering and VLP assembly. Fifteen Ty3 NC Ala substitution and deletion mutants were examined using transposition, immunoblot, RNA protection, cDNA synthesis, and multimerization assays. Localization of Ty3 proteins and VLPs was characterized microscopically. Substitutions of each of the conserved residues of the zinc-binding motif resulted in the loss of Ty3 RNA packaging. Substitution of the first two of four conserved residues in this motif caused the loss of Ty3 RNA and protein clustering with P bodies and disrupted particle formation. NC was shown to be a mediator of formation of Ty3 RNA foci and association of Ty3 RNA and protein with P bodies. Mutations that disrupted these NC functions resulted in various degrees of Gag3 nuclear localization and a spectrum of different particle states. Our findings are consistent with the model that Ty3 assembly is associated with P-body components. We hypothesize that the NC domain acts as a molecular switch to control Gag3 conformational states that affect both assembly and localization.
Fusogenicity of Jaagsiekte Sheep Retrovirus Envelope Protein Is Dependent on Low pH and Is Enhanced by Cytoplasmic Tail Truncations
Authors: Côté Marceline , Zheng Yi-Min , Albritton Lorraine M. , Liu Shan-Lu
Published: December 2007

Jaagsiekte sheep retrovirus (JSRV) envelope (
Env
) is an active oncogene responsible for neoplastic transformation in animals and cultured cells. In this study, we used syncytium induction and fluorescence-based cell fusion assays to investigate JSRV Env fusion and its modulation by the cytoplasmic tail (CT). We found that JSRV Env induced syncytia in cells overexpressing the receptor for JSRV and that a low pH was required for this process to occur. Fusion kinetics studies revealed that cell-cell fusion by JSRV Env at neutral pH was poor, taking up to a day, in sharp contrast to fusion at low pH, which peaked within 2 min following a low-pH trigger. Deletion of the C-terminal 7 or 16 amino acids of the JSRV Env CT had no or little effect on fusion, yet additional truncation toward the membrane-spanning domain, resulting in mutants retaining as little as 1 amino acid of the CT, led to progressively increased syncytium formation at neutral pH that was further enhanced by low-pH treatment. Notably, the severely truncated mutants showed elevated levels of surface subunits in culture medium, suggesting that the CT truncations resulted in conformational changes in the ectodomain of Env that impaired surface subunit associations. Taken together, this study reveals for the first time that the fusion activity of the JSRV Env protein is dependent on a low pH and is modulated by the CT, whose truncation overcomes, at least partially, the low-pH requirement for fusion and enhances Env fusion activity and kinetics.