bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction charge detector with multiple sensing stages
Authors: Gamero-Castaño Manuel
Published: April 2007

An induction charge detector yields the net charge and the time of flight of a particle. The unique ability to independently measure these two parameters sets apart this rather simple detection technique. The main shortcoming of this instrument is its high charge detection limit, resulting from the intrinsic noise of the detector electronics and the low signal associated with the charge to measure. The goal of the present work is to lower the detection limit of this detector. This article describes an induction charge detector whose main novelty is a sequence of aligned cylindrical electrodes for measuring the charge of a particle n times. In a time domain analysis, this feature reduces both the detection limit and the standard error of the charge measurement by factors of 2 and n. More importantly, sensing stages could be added to arbitrarily lower the detection limit in a frequency domain analysis.
Surface segregation and surface tension of polydisperse polymer melts
Authors: Minnikanti Venkatachala S. , Qian Zhenyu , Archer Lynden A.
Published: April 2007

The effect of polydispersity on surface segregation of a lower molecular weight polymer component in a higher molecular weight linear polymer melt host is investigated theoretically. We show that the integrated surface excess zM of a polymer component of molecular weight M satisfies a simple relation zM=2Ue(M∕Mw−1)φM, where Mw is the weight averaged molecular weight, φM is the polymer volume fraction, and Ue is the attraction of polymer chain ends to the surface. Ue is principally of entropic origin, but also reflects any energetic preference of chain ends to the surface. We further show that the surface tension γM of a polydisperse melt of high molar mass components depends on the number average degree of polymerization Mn as, γM=γ∞+2UeρbRT∕Mn. The parameter γ∞ is the asymptotic surface tension of an infinitely long polymer of the same chemistry, ρb is the bulk density of the polymer, R is the universal gas constant, and T is the temperature. The predicted γM compare favorably with surface tension values obtained from self-consistent field theory simulations that include equation of state effects, which account for changes in polymer density with molecular weight. We also compare the predicted surface tension with available experimental data.
Extraordinarily wide-view and high-transmittance vertically aligned liquid crystal displays
Authors: Lin Chi-Huang
Published: April 2007

A compensation method that uses uniaxial films is developed for widening the viewing angle of the high-transmittance multidomain vertical-alignment liquid crystal display (MVA-LCD). Based on this design, the high-transmittance MVA-LCD is predicted to have a complete 80° viewing cone for contrast ratio (CR)>100:1. Experimental results indicate that the real high-transmittance MVA-LCD panel has a viewing angle more than the entire 80° viewing cone for CR>30:1. Potential application as a mobile display is emphasized.
Rapid production of ultralong amorphous ceramic nanofibers by laser spinning
Authors: Quintero F. , Mann A. B. , Pou J. , Lusquiños F. , Riveiro A.
Published: April 2007

Amorphous nanofibers of several centimeters in length can be grown in microseconds during laser cutting of ceramics if a supersonic gas jet is used to clear the cut edge. Such rapid growth is not achievable with vapor phase or solution based methods. Instead, the growth mechanism involves elongation of very small volumes of molten ceramic by frictional drag action of the gas jet. Analysis of the elongation process shows that rapid elongation and cooling are essential to prevent surface tension causing spheroid formation. Using a modified geometry, the process can be adapted to produce near-continuous nanofibers with tailored compositions.
Electronic spectra of jet-cooled calix[4]arene and its van der Waals clusters: Encapsulation of a neutral atom in a molecular bowl
Authors: Ebata Takayuki , Hodono Yuki , Ito Takafumi , Inokuchi Yoshiya
Published: April 2007

The encapsulation of neutral guest has been studied for calix[4]arene (C4A) by forming van der Waals clusters with Ar and Ne in supersonic jets. The electronic transitions of these clusters suggest that the first Ar (Ne) is encapsulated inside the C4A cavity, while the next atoms are bound outside.
Individuals in foraging groups may use vocal cues when assessing their need for anti-predator vigilance
Authors: Radford Andrew N , Ridley Amanda R
Published: April 2007

Many studies of social species have reported variation in the anti-predator vigilance behaviour of foraging individuals depending on the presence and relative position of other group members. However, little attention has focused on how foragers assess these variables. It is commonly assumed that they do so visually, but many social species produce frequent calls while foraging, and these ‘close’ calls might provide valuable spatial information. Here, we show that foraging pied babblers (Turdoides bicolor) are less vigilant when in larger groups, in the centre of a group and in closer proximity to another group member. We then show that foragers are less vigilant during playbacks of close calling by more individuals and individuals on either side of them when compared with calls of fewer individuals and calls on one side of them. These results suggest that foragers can use vocal cues to gain information on group size and their spatial position within a group. Future studies of anti-predator vigilance should consider the relative importance of both visual and vocal monitoring of group members.
Minimum mass vascular networks in multifunctional materials
Authors: Williams H.R , Trask R.S , Weaver P.M , Bond I.P
Published: April 2007

A biomimetic analysis is presented in which an expression for the optimum vessel diameter for the design of minimum mass branching or vascular networks in engineering applications is derived. Agreement with constructal theory is shown. A simple design case is illustrated and application to more complex cases with branching networks of several generations discussed. The analysis is also extended into the turbulent flow regime, giving an optimization tool with considerable utility in the design of fluid distribution systems. The distribution of vessel lengths in different generations was also found to be a useful design variable. Integrating a network into a structure is also discussed. Where it is necessary to adopt a non-optimum vessel diameter for structural integration, it has been shown that small deviations from the minimum mass optimum can be tolerated, but large variations could be expected to produce a punitive and rapidly increasing mass penalty.
Spectral properties of trinomial trees
Authors: Mijatović Aleksandar
Published: April 2007

In this paper, we prove that the probability kernel of a random walk on a trinomial tree converges to the density of a Brownian motion with drift at the rateO(h4), wherehis the distance between the nodes of the tree. We also show that this convergence estimate is optimal in which the density of the random walk cannot converge at a faster rate. The proof is based on an application of spectral theory to the transition density of the random walk. This yields an integral representation of the discrete probability kernel that allows us to determine the convergence rate.
Habitat-specific adaptation of immune responses of stickleback (Gasterosteus aculeatus) lake and river ecotypes
Authors: Scharsack Jörn P , Kalbe Martin , Harrod Chris , Rauch Gisep
Published: April 2007

Freshwater populations of three-spined sticklebacks (Gasterosteus aculeatus) in northern Germany are found as distinct lake and river ecotypes. Adaptation to habitat-specific parasites might influence immune capabilities of stickleback ecotypes. Here, naive laboratory-bred sticklebacks from lake and river populations were exposed reciprocally to parasite environments in a lake and a river habitat. Sticklebacks exposed to lake conditions were infected with higher numbers of parasite species when compared with the river. River sticklebacks in the lake had higher parasite loads than lake sticklebacks in the same habitat. Respiratory burst, granulocyte counts and lymphocyte proliferation of head kidney leucocytes were increased in river sticklebacks exposed to lake when compared with river conditions. Although river sticklebacks exposed to lake conditions showed elevated activation of their immune system, parasites could not be diminished as effectively as by lake sticklebacks in their native habitat. River sticklebacks seem to have reduced their immune-competence potential due to lower parasite diversity in rivers.
Diverse molecular data demonstrate that commercially available medicinal leeches are notHirudo medicinalis
Authors: Siddall Mark E , Trontelj Peter , Utevsky Serge Y , Nkamany Mary , Macdonald Kenneth S
Published: April 2007

The European medicinal leech is one of vanishingly few animal species with direct application in modern medicine. In addition to the therapeutic potential held by many protease inhibitors purified from leech saliva, and notwithstanding the historical association with quackery,Hirudo medicinalishas been approved by the United States Food and Drug Administration as a prescription medical device. Accurate annotation of bioactive compounds relies on precise species determination. Interpretations of developmental and neurophysiological characteristics also presuppose uniformity within a model species used in laboratory settings. Here, we show, with mitochondrial sequences and nuclear microsatellites, that there are at least three species of European medicinal leech, and that leeches marketed asH. medicinalisare actuallyHirudo verbana. Beyond the obvious need for reconsideration of decades of biomedical research on this widely used model organism, these findings impact regulatory statutes and raise concerns for the conservation status of European medicinal leeches.
Histone modifications around individual BDNF gene promoters in prefrontal cortex are associated with extinction of conditioned fear
Authors: Bredy Timothy W. , Wu Hao , Crego Cortney , Zellhoefer Jessica , Sun Yi E. , Barad Mark
Published: April 2007

Extinction of conditioned fear is an important model both of inhibitory learning and of behavior therapy for human anxiety disorders. Like other forms of learning, extinction learning is long-lasting and depends on regulated gene expression. Epigenetic mechanisms make an important contribution to persistent changes in gene expression; therefore, in these studies, we have investigated whether epigenetic regulation of gene expression contributes to fear extinction. Since brain-derived neurotrophic factor (BDNF) is crucial for synaptic plasticity and for the maintenance of long-term memory, we examined histone modifications around two BDNF gene promoters after extinction of cued fear, as potential targets of learning-induced epigenetic regulation of gene expression. Valproic acid (VPA), used for some time as an anticonvulsant and a mood stabilizer, modulates the expression of BDNF, and is a histone deacetylase (HDAC) inhibitor. Here, we report that extinction of conditioned fear is accompanied by a significant increase in histone H4 acetylation around the BDNF P4 gene promoter and increases in BDNF exon I and IV mRNA expression in prefrontal cortex, that VPA enhances long-term memory for extinction because of its HDAC inhibitor effects, and that VPA potentiates the effect of weak extinction training on histone H4 acetylation around both the BDNF P1 and P4 gene promoters and on BDNF exon IV mRNA expression. These results suggest a relationship between histone H4 modification, epigenetic regulation of BDNF gene expression, and long-term memory for extinction of conditioned fear. In addition, they suggest that HDAC inhibitors may become a useful pharmacological adjunct to psychotherapy for human anxiety disorders.
Does a sexually selected trait represent a burden in locomotion?
Authors: Kruesi K. , Alcaraz G.
Published: April 2007

This study tested the hypothesis that in Montezuma swordtail Xiphophorus montezumae, bearers of longer swords would face higher costs in terms of swimming speed than males with shorter swords, as a result of differences in total body length when natural swords were present. Variation in natural sword length, however, did not appear to be correlated with the cost in terms of critical swimming speed, Ucrit. On the other hand, the mean Ucrit of males with the sword excised was 21% higher than that when natural sword was present. This study suggests that the sword of Montezuma swordtail represents a disadvantage in terms of swimming performance regardless of the differences in sword length.
The tale of the bad stepfather: male three‐spined sticklebacks Gasterosteus aculeatus L. recognize foreign eggs in their manipulated nest by egg cues alone
Authors: Frommen J. G. , Brendler C. , Bakker T. C. M.
Published: April 2007

The ability to discriminate between own and foreign eggs was investigated in brood‐caring male three‐spined sticklebacks Gasterosteus aculeatus. Males totally cannibalized clutches that contained both foreign and their own eggs significantly more often than sham‐manipulated control clutches that only contained their own eggs. These results show that caring males are able to recognize the presence of foreign eggs by egg cues alone.
Seasonal changes in ionoregulatory variables of the glass eel Anguilla anguilla following estuarine entry: comparison with resident elvers
Authors: Wilson J. M , Reis‐Santos P. , Fonseca A.‐V. , Antunes J. C. , Bouça P. D. , Coimbra J.
Published: April 2007

In the present study, glass eels Anguilla anguilla in the Minho River estuary (41·5° N, 8·5° W) decreased in size (standard length, LS and mass, M) from the beginning (autumn) to the end of the sampling season (summer). On the other hand elvers increased in LS and M from spring to summer and were significantly larger than glass eels in paired comparisons. Branchial Na+/K+‐ATPase and vacuolar (V‐type) proton ATPase (in vitro activities), two important ion transporting pumps, did not show significant seasonal changes in either glass eels or elvers although in glass eels Na+/K+‐ATPase (activity) expression was significantly higher than in elvers. In a single month comparison Na+/K+‐ATPase branchial mRNA expression was also higher in glass eels as was the protein level expression of both Na+/K+‐ATPase and NKCC (Na+:K+:2Cl− co‐transporter). Immunofluorescence microscopy indicated apical CFTR Cl− channel labelling in Na+/K+‐ATPase positive chloride cell in glass eels which was absent in elvers. Whole body sodium concentration and percentage water did not show significant seasonal differences in either glass eels or elvers although there were significant differences between these two groups during some months.
Evaluating performance costs of sexually selected traits
Authors: OUFIERO C. E. , GARLAND T.
Published: April 2007

Aspects of locomotor performance are thought to be important in a variety of natural contexts, including foraging and escaping from predators. The role of locomotor abilities in sexual selection is less well documented, but is probably of wide importance.

Sexual selection may exaggerate traits beyond their optimum with respect to biomechanical or physiological function, thus imposing ‘costs’ of various types. Locomotor performance, in conjunction with its lower‐level determinants and its behavioural and ecological consequences, constitutes an ideal set of phenotypes with which to study such costs.

Organisms may possess traits that compensate for the negative effects of sexually selected traits on performance abilities. Ignoring these may lead to erroneous conclusions about the cost of a putatively sexually selected trait. At the same time, ignoring the effects of sexual selection on functionally important traits may lead us to underestimate their functional significance.

Many properties of organisms are affected by, or at least correlate with, overall body size, so this must be considered in any study of adaptation or sexual selection. For interspecific or interpopulation comparative studies, phylogeny must also be considered in statistical analyses.

We present a hypothetical data set that illustrates the perils of ignoring potential compensatory mechanisms when studying the costs of a sexually selected trait. We also discuss different ways of studying costs, including analyses of a single sex and of the differences between the sexes.
Predicting grazing damage by white‐fronted geese under different regimes of agricultural management and the physiological consequences for the geese
Authors: AMANO TATSUYA , USHIYAMA KATSUMI , FUJITA GO , HIGUCHI HIROYOSHI
Published: April 2007

One of the most common human–wildlife conflicts is damage by wildlife to agricultural crops. In order to propose cost‐effective measures to address wildlife damage and also to manage pest animals that are of conservation interest, both the effects of wildlife on agricultural crop yield and the effects of mitigation measures on wildlife must be evaluated.

In this study, we applied a behaviour‐based model to the conflict between agricultural production and white‐fronted geese Anser albifrons causing damage to wheat crops around Lake Miyajimanuma in northern Japan. The model is spatially explicit, individual‐ and physiology based, and therefore tracks the day‐to‐day spatial distribution of geese and the physiological dynamics of fat deposition by each goose throughout the staging period.

In our simulations, the establishment of alternative feeding areas (AFAs) for the geese was predicted to be cost‐effective for alleviating wheat damage if the number of AFAs and the amount of alternative food supplied was balanced carefully. However, even with the most cost‐effective combination, a reduction of up to 23% in heavily damaged areas was the best outcome that could be achieved.

Alternatively, locating wheat fields further away from the roost site and also encouraging farmers to leave rice grain remains, the main food resource for the geese, could greatly reduce wheat damage without a detrimental impact on the geese (measured in terms of fat deposition) over a wide range of simulated population sizes.

Synthesis and applications. The suggested combination of mitigation measures (relocation of wheat fields and inhibition of rice‐reducing agricultural practices) should qualify to be tested in practice for alleviating agriculture–geese conflicts in the study area. This study demonstrates that behaviour‐based models can be applied successfully to agriculture–wildlife conflicts, allowing us to evaluate the effects of mitigation measures by quantitative predictions. Behaviour‐based models can be applied to most cases of agriculture–wildlife conflicts involving adaptive foraging behaviour of animals.
Potential ecological and epidemiological factors affecting the persistence of classical swine fever in wild boarSus scrofapopulations
Authors: KRAMER‐SCHADT S. , FERNÁNDEZ N. , THULKE H.‐H.
Published: April 2007

Classical swine fever has increased in economic importance since it has become endemic in some wild boarSus scrofapopulations in Europe. The mechanism of disease persistence is still not well understood, and several aspects of both the ecology of boar and the virus are claimed to be responsible for disease persistence.

We review literature on the spread and persistence of the disease in free‐ranging wild boar. We determine whether the available knowledge can explain the observed patterns via mechanistic processes and their interactions, and assemble knowledge in a conceptual model.

We speculate that the most important factor explaining disease persistence is an alteration in disease outcome, resulting in individual courses with prolonged infectiousness or a sustained reproductive population through immunity. This effect is reinforced by high wild boar numbers either within sites or scattered over larger areas.

We highlight the sparse knowledge of disease transmission between wild boar. We derive management suggestions for different phases of an outbreak based on the conceptual model and advocate the use of model‐based investigations to test alternative management options.
Early responses associated with chronic pathology in murine schistosomiasis
Authors: CÊTRE‐SOSSAH C. B. , MONTESANO M. A. , FREEMAN G. L. , WILLARD M. T. , COLLEY D. G. , SECOR W. E.
Published: April 2007

Inbred male CBA/J mice infected with Schistosoma mansoni develop either hypersplenomegaly syndrome (HSS) or moderate splenomegaly syndrome (MSS) by 20 weeks of infection. Pathologically and immunologically, MSS and HSS closely parallel the intestinal and hepatosplenic clinical forms of schistosomiasis in humans, respectively. By 6 weeks after infection, mice that eventually will become MSS develop T cell‐stimulatory, cross‐reactive idiotypes (CRI) while HSS mice never produce CRI. Because presence of CRI is useful to predict degree of chronic pathology, we used this measure to investigate what other early immunological events occurred in animals destined to develop severe morbidity. At 8 weeks of infection, there was a strong inverse correlation between CRI and splenomegaly, egg counts, and liver hydroxyproline. Similarly, phorbol myristate acetate (PMA)‐ and ionomycin‐stimulated intracellular cytokine expression of IL‐4, IL‐5, and GM‐CSF in splenic CD4+ T cells was inversely correlated with serum CRI and directly correlated with spleen size. In contrast, spleen cell intracellular TNF‐α and peritoneal cell production of nitric oxide demonstrated positive correlations with CRI and inverse correlations with measures of morbidity. Surprisingly, IL‐10 and IFN‐γ were not correlated with CRI levels. These studies link chronic pathology to certain immunological responses during the acute phase of schistosomiasis.
Effect of extending the platelet storage time on platelet utilization: predictions from a mathematical model of prophylactic platelet support
Authors: Pereira A. , Sanz C.
Published: April 2007

summary Bacterial culturing (BCU) or photochemical treatment (PCT) of platelet (PLT) concentrates may permit extending the storage time to 7 days at the cost of decreased viability of transfused PLTs. This study was aimed at predicting the impact this may have on the routine management of patients on prophylactic PLT support.

The method included a mathematical model that represents the dynamics of prophylactic PLT support with standard, BCU or PCT PLTs. Data on posttransfusion PLT kinetics and the effect of PCT or storage time on PLT recovery and survival were obtained from published studies.

Variables that influenced the level of PLT usage were the proportion of transfusions supplied with PLT on the last day of shelf‐life, the use of PCT and the assumed degree of synergy between clinical factors of PLT consumption and either PCT or storage time. In the reference‐case scenario, extending the PLT shelf‐life to 7 days by BCU or PCT increased by 9 and 19%, respectively, the number of PLT transfusions per patient‐year. In the worst‐case scenario, these figures rose to 27 and 38%, respectively. Despite more intensive PLT usage, in most scenarios, the time that patients spent at PLT counts <10 × 109 L−1 increased.

Extending the shelf‐life of PLT products will increase PLT usage. Such increase may be disproportionately larger for patients with complex conditions if there is a synergic interaction between storage time or PCT and clinical factors of PLT consumption, an issue that is worth further clinical research.
Role of anti‐human leucocyte antigen class II alloantibody and monocytes in development of transfusion‐related acute lung injury
Authors: Nishimura M. , Hashimoto S. , Takanashi M. , Okazaki H. , Satake M. , Nakajima K.
Published: April 2007

summary Recently, evidence implicating the roles of the anti‐human leucocyte antigen (HLA) class II antibody in the development of transfusion‐related acute lung injury (TRALI), which is one of the most serious possible side effects of transfusion, has been accumulating. The aim of this study is to clarify the roles of the anti‐HLA DR alloantibody in TRALI development. Cultured human lung microvascular endothelial (LME) cells were incubated with either HLA‐DR15‐positive or HLA‐DR15‐negative monocytes together with serum from a single multiparous donor previously implicated in a clinical case of TRALI and known to contain anti‐HLA DR15 antibody. Production of soluble leukotriene B4 (LTB4) was measured in the supernatant and found to be markedly increased in the presence of HLA‐DR15‐positive monocytes but not with the HLA‐DR15‐negative monocytes or in the absence of LME cells. The vascular cell adhesion molecule‐1 expression in LME cells and leucocyte‐function‐associated molecule‐1 (LFA‐1) expression in HLA‐DR15‐positive monocytes were notably enhanced after combined culture of LME cells, HLA‐DR15‐positive monocytes and TRALI‐inducing anti‐HLA DR15 antibody‐positive serum. In conclusion, anti‐HLA DR alloantibodies may be implicated in LME dysfunction that leads to TRALI, in a monocyte‐dependent manner.
Processing of stored packed red blood cells using autotransfusion devices decreases potassium and microaggregates: a prospective, randomized, single‐blinded in vitro study
Authors: Westphal‐Varghese B. , Erren M. , Westphal M. , Van Aken H. , Ertmer C. , Lange M. , Booke M.
Published: April 2007

summary The aim of the study was to compare the potential of autotransfusion devices to reduce non‐infectious complications related to transfusion of long‐stored packed red blood cells (PRBC; n= 57), such as changes in electrolytes, blood cells and the load of free microaggregates. Following a baseline measurement, a blood pool of three PRBC was divided into three equal volumes and washed with either the Haemonetics Cell Saver™ (HCS) or the continuous autotransfusion system (C.A.T.S™), using the quality (CATSquality) and emergency (CATSemergency) mode. After the washing procedure, measurements for electrolytes, blood cells and free microaggregates were repeated (n= 19 each). Compared with baseline, the investigated autotransfusion devices reduced the median load of potassium (baseline: 52 mEq L−1; HCS: 4 mEq L−1; CATSquality: 4 mEq L−1; CATSemergency: 17 mEq L−1; each P < 0·001), restored a physiologic electrolyte balance and significantly decreased the load of leucocytes, glucose and protein. Whereas the quantity of microaggregates was not reduced by HCS, CATSemergency decreased the load of cell fragments below 7·8 μm (P < 0·05 vs. baseline). Using CATSquality decreased the load of cell fragments not only to a diameter below 7·8 μm (P < 0·001 vs. baseline) but also of microaggregates between 7·8 and 17·6 μm (P < 0·05 vs. baseline). In situations where long‐stored PRBC have to be transfused, the procedure described here may be feasible to reduce clinically relevant side effects, i.e. hyperkalaemia and microvascular obstruction secondary to free cell fragments. This approach could be especially useful in patients undergoing massive transfusion and/or suffering from renal failure.
Successful control of Scedosporium prolificans septic arthritis and probable osteomyelitis without radical surgery in a long‐term renal transplant recipient
Authors: Li J.Y.Z. , Yong T.Y. , Grove D.I. , Coates P.T.H.
Published: April 2007

Abstract: Scedosporium species are increasingly isolated from immunocompromised and immunocompetent patients. Scedosporium infections are generally resistant to multiple antifungals, and Scedosporium prolificans is particularly resistant to all single antifungal agents currently in use with in vitro testing. We report here a long‐term renal transplant recipient who developed isolated S. prolificans septic monoarthritis and probable osteomyelitis. The infection was successfully treated with a combination of voriconazole and terbinafine in addition to joint washout but did not require radical surgery. This combination has been shown to have synergistic in vitro effect, and anecdotal in vivo success has also been reported recently. We also review the clinical presentation, treatment, and outcome of S. prolificans infection in patients with solid organ transplantation.
Ludwik Zamenhof: a colleague of rare distinction
Authors: Littlewood Kenneth R
Published: April 2007

Abstract

Ludwik Zamenhof trained as an ophthalmologist in Vienna at the end of the 19th century. He is best known as the originator of Esperanto and devoted his life to the ideals of secular humanism and ethnic tolerance. Few individuals left a nobler legacy, yet in a tragic irony when the Nazis invaded Poland in World War Two his family were singled out for persecution.
CD40 promotion of amyloid beta production occurs via the NF‐κB pathway
Authors: Ait‐Ghezala Ghania , Volmar Claude‐Henry , Frieling Jeremy , Paris Daniel , Tweed Miles , Bakshi Pancham , Mullan Michael
Published: April 2007

The CD40 receptor is a member of the tumor necrosis factor (TNF) super‐family of trans‐membrane receptors. Interaction of CD40 with its ligand CD40L mediates a broad range of immune and inflammatory responses in the periphery and in the central nervous system. Recently it has been suggested that CD40/CD40L interaction is involved in amyloid precursor protein (APP) processing and Alzheimer's disease (AD)‐like pathology in transgenic mouse models of AD. We have previously shown that pharmacologically inhibiting CD40/CD40L interaction improves memory deficits in the PSAPP AD mouse model. We have also recently shown that CD40 deficiency mitigates amyloid deposition in APPsw and PSAPP mouse models. In the present report, using human embryonic kidney cells (HEK293) over‐expressing both the APPsw mutation and CD40, we demonstrate that CD40/CD40L interaction directly increases the production of APP metabolites (Aβ 1–40, Aβ 1–42, CTFs, sAPPβ and sAPPα). The results also show that CD40/CD40L interaction affects APP processing via the NF‐κB pathway. Using NFκB inhibitors and SiRNAs to silence diverse elements of the NFκB pathway, we observe a reduction in levels of both Aβ 1–40 and Aβ 1–42. Taken together, our results further suggest that CD40L stimulation may be a key component in AD pathology and that elements of the NF‐κB pathway may be suitable targets for therapeutic approaches against AD.
Forebrain mineralocorticoid receptor overexpression enhances memory, reduces anxiety and attenuates neuronal loss in cerebral ischaemia
Authors: Lai Maggie , Horsburgh Karen , Bae Sung‐Eun , Carter Roderick N. , Stenvers Dirk J. , Fowler Jill H. , Yau Joyce L. , Gomez‐Sanchez Celso E. , Holmes Megan C. , Kenyon Christopher J. , Seckl Jonathan R. , Macleod Malcolm R.
Published: April 2007

The nuclear mineralocorticoid receptor (MR), a high‐affinity receptor for glucocorticoids, is highly expressed in the hippocampus where it underpins cognitive, behavioural and neuroendocrine regulation. Increased neuronal MR expression occurs early in the response to cellular injury in vivo and in vitro and is associated with enhanced neuronal survival. To determine whether increased neuronal MR might be causal in protecting against ischaemic damage in vivo we generated a forebrain‐specific MR‐overexpressing transgenic mouse (MR‐Tg) under the control of the CamKII alpha promoter, and subjected mice to transient cerebral global ischaemia induced by bilateral common carotid artery occlusion for 20 min. We also separately assessed the effects of MR overexpression on hypothalamic–pituitary–adrenal (HPA) axis activity and cognitive and affective functions in noninjured animals. Our results showed that MR‐Tg mice had significantly reduced neuronal death following transient cerebral global ischaemia compared to wild‐type littermates. This effect was not associated with alterations in basal or poststress HPA axis function or in arterial blood pressure. MR‐Tg mice also demonstrated improved spatial memory retention, reduced anxiety and altered behavioural response to novelty. The induction of neuronal MR appears to offer a protective response which has potential therapeutic implications in cerebral ischaemia and cognitive and affective disorders.
The relationship between brain activity and peak grip force is modulated by corticospinal system integrity after subcortical stroke
Authors: Ward Nick S. , Newton Jennifer M. , Swayne Orlando B. C. , Lee Lucy , Frackowiak Richard S. J. , Thompson Alan J. , Greenwood Richard J. , Rothwell John C.
Published: April 2007

In healthy human subjects, the relative contribution of cortical regions to motor performance varies with the task parameters. Additionally, after stroke, recruitment of cortical areas during a simple motor task varies with corticospinal system integrity. We investigated whether the pattern of motor system recruitment in a task involving increasingly forceful hand grips is influenced by the degree of corticospinal system damage. Nine chronic subcortical stroke patients and nine age‐matched controls underwent functional magnetic brain imaging whilst performing repetitive isometric hand grips. Target grip forces were varied between 15% and 45% of individual maximum grip force. Corticospinal system functional integrity was assessed with transcranial magnetic stimulation. Averaged across all forces, there was more task‐related activation compared with rest in the secondary motor areas of patients with greater corticospinal system damage, confirming previous reports. However, here we were primarily interested in regional brain activation, which covaried with the amount of force generated, implying a prominent executive role in force production. We found that in control subjects and patients with lesser corticospinal system damage, signal change increased linearly with increasing force output in contralateral primary motor cortex, supplementary motor area and ipsilateral cerebellum. In contrast, in patients with greater corticospinal system damage, force‐related signal changes were seen mainly in contralesional dorsolateral premotor cortex, bilateral ventrolateral premotor cortices and contralesional cerebellum, but not ipsilesional primary motor cortex. These findings suggest that the premotor cortices might play a new and functionally relevant role in controlling force production in patients with more severe corticospinal system disruption.
Age‐related differences in the local cellular and molecular responses to injury in developing spinal cord of the opossum, Monodelphis domestica
Authors: Lane M. A. , Truettner J. S. , Brunschwig J‐P. , Gomez A. , Bunge M. B. , Dietrich W. D. , Dziegielewska K. M. , Ek C. J. , VandeBerg J. L. , Saunders N. R.
Published: April 2007

Immature spinal cord, unlike adult, has an ability to repair itself following injury. Evidence for regeneration, structural repair and development of substantially normal locomotor behaviour comes from studies of marsupials due to their immaturity at birth. We have compared morphological, cellular and molecular changes in spinal cords transected at postnatal day (P)7 or P14, from 3 h to 2 weeks post‐injury, in South American opossums (Monodelphis domestica). A bridge between severed ends of cords was apparent 5 days post‐injury in P7 cords, compared to 2 weeks in P14. The volume of neurofilament (axonal) material in the bridge 2 weeks after injury was 30% of control in P7‐ but < 10% in P14‐injured cords. Granulocytes accumulated at the site of injury earlier (3 h) in P7 than in P14 (24 h)‐injured animals. Monocytes accumulated 24 h post‐injury and accumulation was greater in P14 cords. Accumulation of GFAP‐positive astrocytes at the lesion occurred earlier in P14‐injured cords. Neurites and growth cones were identified ultrastructurally in contact with astrocytes forming the bridge. Results using mouse inflammatory gene arrays showed differences in levels of expression of many TGF, TNF, cytokine, chemokine and interleukin gene families. Most of the genes identified were up‐regulated to a greater extent following injury at P7. Some changes were validated and quantified by RT‐PCR. Overall, the results suggest that at least some of the greater ability to recover from spinal cord transection at P7 compared to P14 in opossums is due to differences in inflammatory cellular and molecular responses.
Detection psychophysics of intracortical microstimulation in rat primary somatosensory cortex
Authors: Butovas Sergejus , Schwarz Cornelius
Published: April 2007

A problem of purposeful intracortical microstimulation is the long duration of neuronal integration time and the associated complex temporal interactions of effects to individual pulses in trains. Here we investigated the effects of repetitive stimuli on perception. We trained head‐restraint rats to indicate the detection of cortical microstimulation in infragranular layers of barrel cortex. Three stimulus parameters: stimulus intensity, number of pulses and frequency were varied, and psychometric detection curves were assessed using the method of constant stimuli. The average psychophysical threshold of single pulses was 2.0 nC − a measure very close to what has been found earlier for the evocation of short‐latency action potentials in neurons near the stimulation electrode. Detection of single‐pulse stimulation always saturated at probabilities of about 0.8. In contrast, repetitive stimuli gave rise to lower thresholds (by a factor of two at 15 pulses, 320 Hz), and to saturation at probabilities close to 1. Interestingly, a large fraction of these perceptual benefits was observed already with double pulses. Moreover, the perceptual efficacy of individual pulses was higher using double pulses compared with longer sequences, i.e. double pulses were detected better than expected from the assumption of independence of single‐pulse effects, while trains of 15 pulses fell well short of this expectation. The present results thus point to double‐pulse stimulation as an optimal choice when trading economic stimulation against optimizing of the percept.
Androgen receptor is essential for sexual differentiation of responses to olfactory cues in mice
Authors: Bodo Cristian , Rissman Emilie F.
Published: April 2007

During sexual differentiation males and females are exposed to different levels of testosterone, which promotes sex differences in the adult brain and in behavior. Testosterone can act after aromatization or reduction via a number of steroid hormone receptors. Here we provide new evidence that the androgen receptor (AR) is essential for sexual differentiation in mice. We used mice carrying the testicular feminization (Tfm) mutation of the AR. Adult Tfm males, wild‐type male and female littermates were gonadectomized and given subcutaneous estradiol implants. In all sexually dimorphic traits, Tfm males had responses equivalent to females and different from males. In simultaneous choice tests, males spent significantly more time investigating female‐soiled bedding, whereas females and Tfm males preferred to investigate male‐soiled bedding. Tfm males and females did not have a partner preference in tests with awake stimulus animals, whereas males showed a preference for females over males. Exposure to male‐soiled, but not clean, bedding produced a significant increase in c‐Fos‐immunoreactive cells in the medial preoptic area and bed nucleus of the stria terminalis in Tfm males and females, no increase was noted in males. Masculine sexual behavior (mounting and thrusting) was not sexually dimorphic, and all groups displayed these behaviors. Our results support data collected in humans suggesting a role for the androgen receptor in sexual differentiation of social preferences and neural responses to pheromones.
PRODUCT IMPROVEMENT AND TECHNOLOGICAL TYING IN A WINNER‐TAKE‐ALL MARKET*
Authors: GILBERT RICHARD J. , RIORDAN MICHAEL H.
Published: April 2007

In a winner‐take‐all duopoly for systems in which firms invest to improve their products, a vertically integrated monopoly supplier of an essential system component may have an incentive to advantage itself by technological tying. If the vertically integrated firm is prevented from technologically tying, there is an equilibrium in which the more efficient firm invests and serves the entire market. However, another equilibrium may exist in which the less efficient firm wins the market. Technological tying enables a vertically integrated firm to foreclose its rival. The welfare implications of technological tying are ambiguous and depend on equilibrium selection.
An evaluation framework of expertise presence in computer conferences
Authors: Lui Andrew K. , Tsang Philip , Kwan Reggie , Ng Sin Chun , Cheung Yannie H. Y. , Choy Sheung On
Published: April 2007

Currently, for educators and researchers, diagnosing the online interactions specifically related to knowledge and expertise exchanges is challenging. To address the problem, this paper describes a framework for the understanding and measurement of expertise presence in computer conferences. Expertise presence is defined as a persistent contribution of knowledge relevant to the purposes of the computer conferences. The paper includes a technique for measuring the strength of expertise presence from transcripts of computer conferences, and it also envisages a number of applications in online learning diagnosis and research. A case study of the application of the framework to the computer conferences of several online courses is discussed.
Preventing Salmon Escapes from Aquaculture in Canada and the USA: Limited International Coordinates, Divergent Regulatory Currents and Possible Future Courses
Authors: Barry Tricia K. , VanderZwaag David L.
Published: April 2007

Following an introductory review of the continuing problem of salmon escaping from aquaculture operations along the Atlantic and Pacific coasts of North America, and the considerable uncertainties over ecological impacts, this article examines the law and policy context for preventing escapes from three perspectives. First, the limited guidance for addressing aquaculture escapes under existing global and regional agreements/arrangements is highlighted. Second, how Canada and the USA have sought to control escape events at national and provincial/State levels is summarized. Third, possible future courses are identified, which improve the way salmon escapes are addressed, with stronger regional responses suggested as most promising. Enhancing the North Atlantic Salmon Conservation Organization's role in preventing escapes and placing transboundary aquaculture issues on the agendas of North Pacific regional cooperative arrangements are the potential courses emphasized.
Computerised screening for visual stress in reading
Authors: Singleton Chris , Henderson Lisa‐Marie
Published: April 2007

Visual stress is the experience of unpleasant visual symptoms when engaged in reading and some other visual tasks. There is currently no objective diagnostic test for this condition, which affects a substantial proportion of the population and which can disrupt development of reading skills. The reliability of subjective reports of symptoms has been questioned, especially where children are concerned. Diagnosis by positive response to the preferred treatment method, either the sustained voluntary use of a coloured overlay or immediate improvement in reading rate when using an overlay, is usually regarded as the best option. Recent research has reported that children who are significantly impaired by a visually stressful pattern during reading‐like visual search are more likely to show significant improvement in reading speed when using an overlay. This study was designed to evaluate a prototype computerised visual stress screener that incorporated visual search. The results confirmed that primary and secondary school children who were classified by the screener as having high susceptibility to visual stress had larger percent increases in reading rate with an overlay compared with those with low visual stress. The results also indicated that subjective reports of symptoms may not always be diagnostically effective with younger populations. It was concluded that screening for visual stress in reading using a computerised visual search task is an educationally promising development.
All Guts, No Glory: Trading and Diversification among Online Investors
Authors: Anderson Anders
Published: April 2007

I explore cross‐sectional portfolio performance in a sample containing 324,736 transactions conducted by 16,831 Swedish investors at an Internet discount brokerage firm during the period May 1999 to March 2002. On average, investors hold undiversified portfolios, show a strong preference for risk, and trade aggressively. I measure performance using a panel data model, and explain the cross‐sectional variation using investors' turnover, portfolio size and degree of diversification. I find that turnover is harmful to performance due to fees, and is therefore more predominant among investors with small portfolios. I argue that the degree of diversification is a proxy for investor skill, and it has a separate and distinct positive effect on performance. Investors underperform the market by about 8.5% per year on average, of which half can be attributed to trading costs.
Joint Venture Regulation under European Competition Laws: An Update
Authors: Tyson Nicole
Published: April 2007

Abstract:  This article examines the European approach to joint venture regulation. It updates previous analysis by examining the impact of modernisation reforms on joint venture regulation in Europe. It is argued that although the changes on the whole are conducive to joint venture activity, problematic aspects of regulation were either unaddressed, or could be provoked by, the reform. In particular, the substantive and procedural divide in legal treatment of ‘concentrative’ and ‘cooperative’ joint venture arrangements continues to engender some difficulty.
Au nom de qui? The European Court of Justice between Member States, Civil Society and Union Citizens
Authors: Wernicke Stephan
Published: April 2007

Abstract:  How does the quest for legitimacy of the European Union relate to the view the European Court of Justice(ECJ) accords to Union citizens, civil society and to private actors? It is submitted that the ECJ is currently developing a jurisprudence under which citizens, as well as their organisations and corporate private actors, are gradually, and in almost complete disregard of the public/private distinction, being included in the matrix of rights and—a crucial point—obligations of the treaties. The ECJ incorporates civil society actors and citizens, beyond notions of representative (citizenship) and participatory (civil society) democracy, into the body of law and thereby reworks its own and the Union's identity. Two core aspects are explored: the first is the reconfiguration of Union citizenship as a norm which triggers the application of the substantive norms of the EC Treaty. The second aspect of this evolution is the creation of ‘private governance’ schemes, i.e. processes in which, as a rule, private action is regarded as action that has to meet the standards of the Treaty. The analysis shows that the court is disentangling itself from the State‐oriented Treaty situation and drawing legitimacy directly from citizens themselves so that judgments should be pronounced ‘In the Name of the Citizens of the European Union’.

‘Union Citizenship is destined to be the fundamental status of nationals of the Member States.’1