bluuebunny/crossref_metadata_2025 huggingface dataset:
Orthogonal transformation of moving grid model into fixed grid model in the finite element analysis of induction machines
Authors: Demenko Andrzej , Stachowiak Dorota
Published: March 2005

The equivalent fixed grid and moving grid models for the finite element (FE) analysis of an induction machine are presented. The discussed transformation is the FE representation of the classical commutator transformation. The obtained fixed grid model takes into account the higher space harmonics of the flux density wave and can be used in the FE analysis of the machines with solid rotor, drug‐cap rotor, and squirrel cage winding. The models have been applied in the calculations of TEAM Workshop problem No. 30. The test problem has been solved analytically. The FE results and analytical results are very close.
A new approach for shape optimization of resistors with complex geometry
Authors: Purcar M. , Deconinck J. , Bortels L. , Munteanu C. , Simion E. , Topa V.
Published: March 2005

This paper presents a new numerical approach for shape optimization of resistors with complex geometry. The aim of this method is to develop a systematic modification of resistor design in combination with the computation of the electric field, in order to optimize some chosen properties like homogenization of the power dissipation on the resistor surface.
FEM analysis of current limiting devices using superconducting thin film and AC losses of YBCO coated conductor
Authors: Ohsaki H. , Ichiki Y. , Sugita S.
Published: March 2005

A numerical analysis tool has been developed to study electromagnetic characteristics of high‐temperature superconducting thin film used for a resistive‐type fault current limiter (FCL) and coated conductor. It adopts the finite element method based on current vector potentials with thin‐plate approximation. Transport current, temperature dependence and strong non‐linearity of electromagnetic properties, and state transition of superconductor are taken into account by solving a three‐dimensional coupled problem of electromagnetic field, an electric circuit and thermal field. Then using this numerical analysis tool the current imbalance and current limiting characteristics of a FCL device, the influence of inhomogeneity of superconducting properties on them, and AC losses in YBCO coated conductor are studied.
Doing critical research in information systems: a case of theory and practice not informing each other*
Authors: McGrath Kathy
Published: March 2005

Abstract.For more than 30 years, critical research in information systems (IS) has challenged the assumption that technology innovation is inherently desirable and hence to the benefit of all. Nevertheless, how researchers view the nature of being critical has changed over time, and so too have the ways that they pursue their critical agenda and argue for their contributions. In this paper, I present a brief historical account of critical IS research, tracing the theoretical perspectives that have been dominant at different times and the empirical efforts that were guided by them. As part of tracing our current position I examine two key texts authored by Chrisanthi Avgerou and Geoff Walsham, who pursue different types of critical agenda and make distinctive empirically based contributions concerning the substantive issue of global diversity in IS innovation and its consequences. Overall, I suggest that the IS field now accepts broad definitions of the nature of being critical, but despite having a body of empirical critical research from which to learn, we are not making the most of our opportunities to do so, which retards further development. While I do not seek to develop a prescription for conducting and evaluating critical research, or try to encourage lengthy confessional accounts of research conduct in all journal papers, I do argue that we need more explicit reflections about our sustained long‐term efforts in the field. Such reflections might consider the way we develop our critical arguments and insights, and what we strive for and accomplish through our interventions. In effect, the IS field has not yet reached a position where the theory and practice of doing critical research are informing each other.
Identification of a bacterial factor required for actin‐based motility of Burkholderia pseudomallei
Authors: Stevens Mark P. , Stevens Joanne M. , Jeng Robert L. , Taylor Lowrie A. , Wood Michael W. , Hawes Pippa , Monaghan Paul , Welch Matthew D. , Galyov Edouard E.
Published: March 2005

Burkholderia pseudomallei is a Gram‐negative facultative intracellular pathogen that enters and escapes from eukaryotic cells using the power of actin polymerization. We have identified a bacterial protein (BimA) that is required for the ability of B. pseudomallei to induce the formation of actin tails. BimA contains proline‐rich motifs and WH2‐like domains and shares limited homology at the C‐terminus with the Yersinia autosecreted adhesin YadA. BimA is located at the pole of the bacterial cell at which actin polymerization occurs and mutation of bimA abolished actin‐based motility of the pathogen in J774.2 cells. Transient expression of BimA in HeLa cells resulted in F‐actin clustering reminiscent of that seen on WASP overexpression. Antibody‐mediated clustering of a CD32 chimera in which the cytoplasmic domain was replaced with BimA resulted in localization of the chimera to the tips of F‐actin enriched membrane protrusions. We report that purified truncated BimA protein binds monomeric actin in a concentration‐dependent manner in cosedimentation assays and that BimA stimulates actin polymerization in vitro in a manner independent of the cellular Arp2/3 complex.
Transcriptional response of Escherichia coli to external copper
Authors: Yamamoto Kaneyoshi , Ishihama Akira
Published: March 2005

Transcriptional response of Escherichia coli upon exposure to external copper was studied using DNA microarray and in vivo and in vitro transcription assays. Transcription of three hitherto‐identified copper‐responsive genes, copA (copper efflux transporter), cueO (multicopper oxidase) and cusC (tripartite copper pump component) became maximum at 5 min after addition of copper sulphate, and thereafter decreased to the preshift levels within 30 min. Microarray analysis at 5 min after addition of copper indicated that a total of at least 29 genes including these three known genes were markedly and specifically affected (28 upregulated and one downregulated). Transcription of the divergent operons, cusCFB and cusRS, was found to be activated by CusR, which bound to a CusR box between the cusC and cusR promoters. Except for this site, the CusR box was not identified in the entire E. coli genome. On the other hand, transcription of copA and cueO was found to be activated by another copper‐responsive factor CueR, which bound to a conserved inverted repeat sequence, CueR box. A total of 197 CueR boxes were identified on the E. coli genome, including the CueR box associated with the moa operon for molybdenum cofactor synthesis. At least 10 copper‐induced genes were found to be under the control of CpxAR two‐component system, indicating that copper is one of the signals for activation of the CpxAR system. In addition, transcription of yedWV, a putative two‐component system, was activated by copper in CusR‐dependent manner. Taken together we conclude that the copper‐responsive genes are organized into a hierarchy of the regulation network, forming at least four regulons, i.e. CueR, CusR, CpxR and YedW regulons. These copper‐responsive regulons appear to sense and respond to different concentrations of external copper.
Importance of unusually modified lipid A in Sinorhizobium stress resistance and legume symbiosis
Authors: Ferguson Gail P. , Datta Anup , Carlson Russ W. , Walker Graham C.
Published: March 2005

Sinorhizobium meliloti, a legume symbiont and Brucella abortus, a phylogenetically related mammalian pathogen, both require their BacA proteins to establish chronic intracellular infections in their respective hosts. The lipid A molecules of S. meliloti and B. abortus are unusually modified with a very‐long‐chain fatty acid (VLCFA; C ≥ 28) and we discovered that BacA is involved in this unusual modification. This observation raised the possibility that the unusual lipid A modification could be crucial for the chronic infection of both S. meliloti and B. abortus. We investigated this by constructing and characterizing S. meliloti mutants in the lpxXL and acpXL genes, which encode an acyl transferase and acyl carrier protein directly involved in the biosynthesis of VLCFA‐modified lipid A. Our analysis revealed that the unusually modified lipid A is important, but not crucial, for S. meliloti chronic infection and that BacA must have an additional function, which in combination with its observed effect on the lipid A in the free‐living form of S. meliloti, is essential for the chronic infection. Additionally, we discovered that in the absence of VLCFAs, S. meliloti produces novel pentaacylated lipid A species, modified with unhydroxylated fatty acids, which are important for stress resistance.
Identification of Salmonella functions critical for bacterial cell division within eukaryotic cells
Authors: Henry T. , García‐del Portillo F. , Gorvel J. P.
Published: March 2005

Salmonella typhimurium multiplication inside eukaryotic host cells is critical for virulence. Salmonella typhimurium strain SL1344 appears as filaments upon growth in macrophages and MelJuSo cells, a human melanoma cell line, indicating a specific blockage in the bacterial cell division process. Several studies have investigated the host cell response impairing bacterial division. However, none looked at the bacterial factors involved in inhibition of Salmonella division inside eukaryotic cells. We show here that blockage in the bacterial division process is sulA‐independent and takes place after FtsZ‐ring assembly. Salmonella typhimurium genes in which mutations lead to filamentous growth within host cells were identified by a large scale mutagenesis approach on strain 12023, revealing bacterial functions crucial for cell division within eukaryotic cells. We finally demonstrate that SL1344 filamentation is a result of hisG mutation, requires the activity of an enzyme of the histidine biosynthetic pathway HisFH and is specific for the vacuolar environment.
Cross‐talk between cAMP and calcium signalling in Aspergillus niger
Authors: Benčina Mojca , Legiša Matic , Read Nick D.
Published: March 2005

Very little is known about cross‐talk between cAMP and calcium signalling in filamentous fungi. The aim of this study was to analyse the influence of cAMP and protein kinase A (PKA)‐dependent phosphorylation on calcium signalling in Aspergillus niger. For this purpose, cytosolic free calcium ([Ca2+]c) was measured in living hyphae expressing codon‐optimized aequorin. The calcium signature following mechanical perturbation was analysed after applying dibutryl‐cAMP or IBMX which increased intracellular cAMP, or H7 which inhibited phosphorylation by PKA. Calcium signatures were also measured in mutant strains in which phosphorylation by PKA was increased or lacking. The results indicated that calcium channels were activated by cAMP‐mediated, PKA‐dependent phosphorylation. Further evidence for cross‐talk between cAMP and calcium signalling came from the analysis of a mutant in which the catalytic subunit of PKA was under the control of an inducible promoter. The consequence of PKA induction was a transient increase in [Ca2+]c which correlated with a polar–apolar transition in hyphal morphology. A transient increase in [Ca2+]c was not observed in this mutant when the morphological shift was in the opposite direction. The [Ca2+]c signatures in response to mechanical perturbation by polarized and unpolarized cells were markedly different indicating that these two cell types possessed different calcium signalling capabilities. These results were consistent with PKA‐dependent phosphorylation increasing [Ca2+]c to induce a polar to apolar shift in hyphal morphology.
Identification of cyanobacterial cell division genes by comparative and mutational analyses
Authors: Miyagishima Shin‐ya , Wolk C. Peter , Osteryoung Katherine W.
Published: March 2005

We performed comparative and mutational analyses to define more comprehensively the repertoire of genes involved in cyanobacterial cell division. Genes ftsE, ftsI, ftsQ, ftsW, and (previously recognized) ftsZ, minC, minD, minE and sulA were identified as homologues of cell division genes of Gram‐negative and Gram‐positive bacteria. Transposon mutagenesis of Synechococcus elongatus PCC 7942 identified five additional genes, cdv1, cdv2, cdv3, ftn6 and cikA, involved in cell division. cdv1 encodes a presumptive periplasmic peptidyl‐prolyl cis‐trans isomerase. cdv2 has similarity to ylmF which, like divIVA, lies within the Gram‐positive bacterial ylm gene cluster whose members have functions associated with division. Conservation of other ylm genes in cyanobacteria suggests that cyanobacteria and Gram‐positive bacteria share specific division proteins. Two ylm homologues are also found in algal and plant genomes. cdv3 has low but significant similarity to divIVA, suggesting that minE and cdv3 both mediate division‐site determination in cyanobacteria. In contrast, Gram‐positive bacteria lack minE, and (Gram‐negative) proteobacteria lack divIVA. ftn6, of unknown function, and the circadian input kinase, cikA, are specific to cyanobacteria. In S. elongatus, unlike in other bacteria, FtsZ rings are formed at sites occupied by nucleoids. Thus, the division machinery of cyanobacteria differs in its composition and regulation from that of Gram‐negative and Gram‐positive bacteria.
Therapeutic efficacy of isosorbide dinitrate for dysphagia after endoscopic injection sclerotherapy for varices in cirrhotic patients
Authors: Kakinuma Toru , Shimoji Katsunori , Imai Yukinori , Fujiwara Kenji
Published: March 2005

Background: Isosorbide dinitrate (ID) improves dysphagia of achalasia patients by lowering the low esophageal pressure. Dysphagia occurs in cirrhotic patients undergoing endoscopic injection sclerotherapy (EIS) for esophageal varices even with no structural abnormalities as its sequela. We tested whether ID can be therapeutic for dysphagia of this type.

Methods: ID was given for 2–6 weeks to 13 patients with dysphagia lasting for longer than 4 weeks after EIS despite no esophagolumenal stricture on endoscopy and barium swallows. EIS was done three to six times as an injection series of ethanolamine oleate into the varices at intervals of 1–2 weeks until they were obliterated. The therapeutic efficacy of ID was evaluated by symptom severity four‐degree scorings. Esophageal transit time and emptying time were calculated from the time–activity curves on esophageal scintigraphy.

Results: At 2 weeks after ID medication, dysphagia was decreased by one score in 12 of 13 patients, and by two scores in one patient. However, dysphagia at the same extent recurred in nine patients within 6 weeks after stopping ID medication, which was improved similarly by remedication. Two patients in whom dysphagia of one and two scores disappeared after ID medication dropped out because of headache. The remaining two patients remained asymptomatic for longer than 6 months after the first medication. Esophageal scintigraphy disclosed the shortening of the emptying time after ID administration in two patients.

Conclusions: ID may be effective for relieving functional dysphagia after EIS for esophageal varices in cirrhotic patients.
Assessment of transendoscopic miniature ultrasonic probe for chemoradiotherapy outcome in patients with locally advanced esophageal cancer
Authors: Iwase Hiroaki , Shimada Masaaki , Tsuzuki Tomoyuki , Doi Reiko , Okeya Masayuki , Kobayashi Keiko
Published: March 2005

Background: Assessment of the response of esophageal cancer to chemoradiotherapy is difficult. We investigated the value of a transendoscopic miniature ultrasonic probe (USP) in assessing response to chemoradiotherapy in patients with locally advanced esophageal cancer.

Methods: A total of 33 patients were entered in this prospective study. Response to treatment was evaluated according to World Health Organization criteria. According to the sonographic image, complete response (CR) of the primary lesion was divided into two subcategories: confirmed CR (cCR) and unconfirmed CR (uCR).

Results: Initial sonographic criteria for evaluating tumor depth and lymph nodes in the 33 patients before therapy showed two cases of T2N0, four of T3N0, 15 of T3N1, four of T4N0, and eight of T4N1. Following chemoradiotherapy, CR was obtained in 18 (54.5%): seven cCR and 11 uCR. Eleven were partial response (PR) (33.3%), while three were stable disease (SD) and one was progressive disease (PD). High frequency USP (20 MHz) was able to detect tumor disappearance and restoration of the esophageal wall. One‐year survival rates among CR (cCR + uCR), PR and SD + PD were 100%, 70% and 0%, respectively. A significant difference in survival was evident among CR, PR and SD + PD (P < 0.001). Three‐year survival rates between cCR and uCR were 100% and 40%, respectively. A significant difference in survival was evident between cCR and uCR (P < 0.001). In seven cases of uCR, local recurrence and distant metastasis appeared within 1 year, and five died of disease progression. Not one cCR case has relapsed.

Conclusion: USP, which can be accomplished with a standard endoscopy, including biopsy, in one procedure, is a useful method for objectively assessing the response to chemoradiotherapy in patients with locally advanced esophageal cancer.
A new type of hemoclip device
Authors: Watanabe Kenichi , Itoh Akemi , Kobayashi Kenji , Suzuki Takayoshi , Shirai Takayuki , Mine Tetsuya
Published: March 2005

Background: There are many endoscopic techniques for hemostasis of non‐variceal upper GI bleeding. Endoscopic hemoclip placement is one of the most important techniques. A rotatable clip‐fixing device developed by Olympus Co. (Tokyo, Japan) has come into widespread use in Japan. However, it involves a number of problems, such as requirement of skill for attachment and it is time‐consuming.

Materials: We developed a new type of hemoclip device with collaboration with Olympus Co.

Results: We explain the new type of hemoclip device and how to use it. Finally, we examine the convenience of the new type of hemoclip compared with previous devices.

Conclusion: Hemoclip placement for bleeding of GI tract seems to be very convenient now and may become common in the world in the future.
Conservative management of duodenal perforation following endoscopic sphincterotomy
Authors: Choong Chee Fook , Chari Suresh , Norton Ian , Cowlishaw James Lawrence
Published: March 2005

Overall endoscopic retrograde cholangiopancreatography (ERCP) complication rates of 4–10% and mortality rates of 1.5% have been reported. For those patients who fail conservative therapy, a mortality rate of almost 50% has been reported. This has led some authors to recommended early operation in all duodenal perforations. We report two cases of duodenal perforations following endoscopic sphincterotomy. Perforation was suspected immediately post‐ERCP in one case and, in the second case, perforation was evident during ERCP and a biliary stent was inserted. Both of the patients were managed conservatively with bowel rest, nasogastric suction, analgesia and intravenous antibiotics. Although abdominal XR and CT showed extensive intraperitoneal and retroperitoneal gas, both of the patients made an uneventful recovery without surgical management. Based on our experience and literature review, routine surgery is not required in patients with duodenal perforations following endoscopic sphincterotomy. Surgery should be considered in any patients with clinical signs of sepsis, abscess or fluid collection in the retroperitoneum or peritoneum, documented ERCP perforation with cholelithiasis, choledocholithiasis or retained hardware. There are currently no strong data to support the benefits of early routine surgery and management should be tailored individually according to the patient's clinical condition and response to therapy.
Investigation of PKC isoform‐specific translocation and targeting of the current of the late afterhyperpolarizing potential of myenteric AH neurons
Authors: Nguyen Trung V. , Poole Daniel P. , Harvey John R. , Stebbing Martin J. , Furness John B.
Published: March 2005

AH neurons in the enteric nervous system play an essential role in initiating intestinal reflexes and factors that control AH neuron excitability therefore influence the state of the digestive system. Prominent afterhyperpolarizations that follow action potentials in these neurons strongly affect their excitability. In the present work, we have investigated the regulation of the afterhyperpolarizing current (IAHP) by protein kinase C (PKC). Electrophysiological responses and protein translocation were investigated in AH neurons of freshly dissected preparations of myenteric ganglia from the guinea‐pig ileum. The activator of conventional and novel PKCs, phorbol dibutyrate, but not the activator of novel PKCs, ingenol, blocked the IAHP. Phorbol dibutyrate had no effect on the hyperpolarization‐activated current (Ih) or on the A current (IA). Stimulation of synaptic inputs to the neurons also reduced the IAHP, and had no effect on Ih or IA. Phorbol dibutyrate also reduced a background outward current that was present after the IAHP current had been blocked by clotrimazole. Both phorbol dibutyrate and ingenol caused translocation of the novel PKC, PKCε, in these neurons. Only phorbol dibutyrate caused translocation of PKCγ, a conventional PKC. The studies thus indicate that the activation of PKC by phorbol esters and by nerve stimulation affects AH neurons in a similar way, and that PKC activation targets both the IAHP and another background K+ current. The IAHP is targeted by a conventional PKC, suggested to be PKCγ, as this is the only conventional PKC that is prominent in AH neurons.
Correlation between multiple climbing fibre regression and parallel fibre response development in the postnatal mouse cerebellum
Authors: Scelfo Bibiana , Strata Piergiorgio
Published: March 2005

At the neuromuscular junction elimination of supernumerary synaptic connections during development is owing to a competitive process between single neuronal populations, whereas in the central nervous system the interaction of different types of input could affect the process. In the cerebellum, the regression from multiple‐ to mono‐innervation of the Purkinje cells by climbing fibres is virtually completed during the first two weeks of postnatal development. While it is clear that parallel fibres are important in the control of the regression, there are conflicting results in relation to whether an early phase of regression is independent of parallel fibre effects. We studied the precise timing of climbing fibre synapse development and decline and the relationship with the functional maturation of parallel fibres. Until postnatal day (P) 6 or 7, the synaptic currents generated by different climbing fibres become progressively more uniform in amplitude. However, between P7 and 14, the amplitudes of the currents increasingly diverge until only one fibre remains connected. These data are taken as evidence that, in multiply innervated Purkinje cells, competition between different climbing fibres appears at P7 and continues during the second postnatal week. Morphological and electrophysiological data demonstrate that parallel fibres synapses appear at P7 and their development is significantly correlated with the time course of the climbing fibre regression. These results provide no evidence for climbing fibre regression independent of parallel fibres before P7 and also suggest a dominant role of the parallel fibre input in the later phase.
Homogeneous distribution of large‐conductance calcium‐dependent potassium channels on soma and apical dendrite of rat neocortical layer 5 pyramidal neurons
Authors: Benhassine Narimane , Berger Thomas
Published: March 2005

Voltage‐gated conductances on dendrites of layer 5 pyramidal neurons participate in synaptic integration and output generation. We investigated the properties and the distribution of large‐conductance calcium‐activated potassium channels (BK channels) in this cell type using excised patches in acute slice preparations of rat somatosensory cortex. BK channels were characterized by their large conductance and sensitivity to the specific blockers paxilline and iberiotoxin. BK channels showed a pronounced calcium‐dependence with a maximal opening probability of 0.69 at 10 µmand 0.42 at 3 µmfree calcium. Their opening probability and transition time constants between open and closed states are voltage‐dependent. At depolarized potentials, BK channel gating is described by two open and one closed states. Depolarization increases the opening probability due to a prolongation of the open time constant and a shortening of the closed time constant. Calcium‐dependence and biophysical properties of somatic and dendritic BK channels were identical. The presence of BK channels on the apical dendrite of layer 5 pyramidal neurons was shown by immunofluorescence. Patch‐clamp recordings revealed a homogeneous density of BK channels on the soma and along the apical dendrite up to 850 µm with a mean density of 1.9 channels per µm2. BK channels are expressed either isolated or in clusters containing up to four channels. This study shows the presence of BK channels on dendrites. Their activation might modulate the shape of sodium and calcium action potentials, their propagation along the dendrite, and thereby the electrotonic distance between the somatic and dendritic action potential initiation zones.
Dynamics of learning‐induced spine redistribution along dendrites of pyramidal neurons in rats
Authors: Knafo Shira , Libersat Frederic , Barkai Edi
Published: March 2005

We have previously shown that olfactory‐discrimination (OD) learning is accompanied by enhanced spine density along proximal apical dendrites of layer II pyramidal neurons in the piriform (olfactory) cortex. Here we studied the temporal dynamics of learning‐induced modifications in dendritic spine density throughout the dendritic trees of these neurons. We observed a transient increase in proximal apical spine density after OD learning, suggesting a strengthening of intrinsic excitatory inputs interconnecting neurons within the olfactory cortex. By contrast, the afferent pathway receiving direct input from the olfactory bulb shows spine pruning, suggesting that the connectivity is weakened. The changes in spine density can be attributed to a net change in number of spines, as the morphometric parameters of the dendrites are unaffected by learning. We suggest that spine density changes may represent a mechanism of selective synaptic reorganization required for olfactory learning consolidation.
The neural correlate of very‐long‐term picture priming
Authors: Meister Ingo G. , Weidemann Jürgen , Foltys Henrik , Brand Henning , Willmes Klaus , Krings Timo , Thron Armin , Töpper Rudolf , Boroojerdi Babak
Published: March 2005

Repetition priming denotes a behavioural change caused by prior exposure to a stimulus. The effect is known to last for weeks. This study addresses the underlying neural mechanisms for very‐long‐term picture priming by using event‐related functional magnetic resonance imaging complemented by a behavioural paradigm. Previous functional imaging studies with shorter retention intervals have shown that priming is associated with changes in the activity of both the occipital and posterior temporal cortex. In this study we compared retention intervals of 1 day and 6 weeks after initial exposure to a picture stimulus. Priming‐related decreases in cortical activity in posterior extrastriate and dorsal left inferior frontal areas were found only for the shorter retention interval. In contrast, fMRI activation in the inferior posterior temporal and anterior left inferior frontal cortex was reduced following priming for both retention intervals. In the behavioural paradigm, the priming effect was stable over time. We conclude that the left inferior frontal and inferior posterior temporal cortex play a key role in the very‐long‐term priming effect.
National Threat and Political Culture: Authoritarianism, Antiauthoritarianism, and the September 11 Attacks
Authors: Perrin Andrew J.
Published: March 2005

This paper uses published letters to the editor of major U.S. newspapers to investigate the cultural effects of a major national threat: the September 11, 2001, terrorist attacks. It is based on a hand‐coded, stratified random sample of 1,100 letters to the editor published in 17 major papers in the United States (544 pre‐September 11, 556 post‐September 11). The letters are drawn from a population of 8,101 published letters. Degrees of both authoritarianism and antiauthoritarianism, as well as the general salience of questions of authoritarianism, rose significantly in the post‐attack period. The paper suggests that, instead of a simple threat‐authoritarianism causal link, authoritarianism and antiauthoritarianism are paired elements of political culture that are invoked together in the face of a national threat.
Threat, Authoritarianism, and Selective Exposure to Information
Authors: Lavine Howard , Lodge Milton , Freitas Kate
Published: March 2005

We examined the hypothesis that threat alters the cognitive strategies used by high authoritarians in seeking out new political information from the environment. In a laboratory experiment, threat was manipulated through a “mortality salience” manipulation used in research on terror management theory (Pyszczynski, Solomon & Greenberg, 2003). Subjects (N = 92) were then invited to read one of three editorial articles on the topic of capital punishment. We found that in the absence of threat, both low and high authoritarians were responsive to salient norms of evenhandedness in information selection, preferring exposure to a two‐sided article that presents the merits of both sides of an issue to an article that selectively touts the benefits of the pro or con side of the issue. However, in the presence of threat, high but not low authoritarians became significantly more interested in exposure to an article containing uniformly pro‐attitudinal arguments, and significantly less interested in a balanced, two‐sided article. Finally, a path analysis indicated that selective exposure to attitude‐congruent information led to more internally consistent policy attitudes and inhibited attitude change. Discussion focuses on the role of threat in conditioning the cognitive and attitudinal effects of authoritarianism.
Stopping-Time Resampling for Sequential Monte Carlo Methods
Authors: Chen Yuguo , Xie Junyi , Liu Jun S.
Published: March 2005

Motivated by the statistical inference problem in population genetics, we present a new sequential importance sampling with resampling strategy. The idea of resampling is key to the recent surge of popularity of sequential Monte Carlo methods in the statistics and engin-eering communities, but existing resampling techniques do not work well for coalescent-based inference problems in population genetics. We develop a new method called ‘stopping-time resampling’, which allows us to compare partially simulated samples at different stages to terminate unpromising partial samples and to multiply promising samples early on. To illustrate the idea, we first apply the new method to approximate the solution of a Dirichlet problem and the likelihood function of a non-Markovian process. Then we focus on its application in population genetics. All our examples show that the new resampling method can significantly improve the computational efficiency of existing sequential importance sampling methods.
Model-Free Variable Selection
Authors: Li Lexin , Dennis Cook R. , Nachtsheim Christopher J.
Published: March 2005

The importance of variable selection in regression has grown in recent years as computing power has encouraged the modelling of data sets of ever-increasing size. Data mining applications in finance, marketing and bioinformatics are obvious examples. A limitation of nearly all existing variable selection methods is the need to specify the correct model before selection. When the number of predictors is large, model formulation and validation can be difficult or even infeasible. On the basis of the theory of sufficient dimension reduction, we propose a new class of model-free variable selection approaches. The methods proposed assume no model of any form, require no nonparametric smoothing and allow for general predictor effects. The efficacy of the methods proposed is demonstrated via simulation, and an empirical example is given.
INFRASTRUCTURE: OPTIMAL PRIVATE AND GOVERNMENTAL FUNDING AND PROVISION
Authors: Foldvary Fred E.
Published: March 2005

The excess burden of taxation, which in the US is over $1 trillion, could be reduced by transferring responsibility for funding infrastructure to the private sector, with a corresponding cut in taxes. While governments may resist optimal taxation, private communities are induced to do so by competition. A promising approach to efficient funding of civic infrastructure is its transfer to private enterprise
THE FISCAL CHALLENGE OF COMPETITIVE MARKETS
Authors: Harrison Fred
Published: March 2005

Competition maximises consumer satisfaction but creates a financial problem for enterprises. When prices are competed down to just cover marginal costs, part of the value added by the enterprise is externalised. Government has not been efficient at recycling that value back into the economy, which is why infrastructure is severely underfunded.
OPTIMAL PRICING: THE ROUTE TO A SELF‐FUNDING INFRASTRUCTURE ‐ AND MORE
Authors: Roy Rana
Published: March 2005

Optimal pricing delivers not only a self‐funding infrastructure but also the additional revenues to reduce economically damaging taxes on capital, labour and final consumption. For the transport sector, this result has now been established by a concerted international research effort. Optimising prices across all modes of transport will ensure the efficient use of existing infrastructure, provide the informational base to optimise investment decisions and generate revenues in excess of both current infrastructure costs and the costs of justified investments.
INSIDE THE‘BLACK BOX’ OF MARKET DISCIPLINE
Authors: Llewellyn David T.
Published: March 2005

This article considers the role of market monitoring and discipline in policy orientated towards maintaining financial stability. Although it is widely assumed that markets have a potentially powerful role in disciplining banks, the precise mechanisms are not always clear. In this sense, market discipline is something of a ‘Black Box’. The purpose of this article is to consider the precise mechanisms within the Black Box and to outline the required conditions for market discipline to be effective. It is found that there is much that policymakers can and should do to enhance the effectiveness of market discipline and to ensure that market discipline is not impeded.
EDUCATIONAL EXPANSION: THE WORMS IN THE APPLE
Authors: Wolf Alison
Published: March 2005

Expansion of higher education can undermine rather than enhance the value of education for low income families. Less well qualified children of higher income families are the main beneficiaries of the expansion and the value of the qualifications of those who do not participate in higher education can be undermined. The most obvious practical policy that would expand educational opportunity for all would be to treat all adult students equally and give further education institutions and universities comparable, as well as greater, freedom from government control.
Astrocyte activation by fibroblast growth factor‐1 and motor neuron apoptosis: implications for amyotrophic lateral sclerosis
Authors: Cassina Patricia , Pehar Mariana , Vargas Marcelo R. , Castellanos Raquel , Barbeito Ana G. , Estévez Alvaro G. , Thompson John A. , Beckman Joseph S. , Barbeito Luis
Published: March 2005

Fibroblast growth factor‐1 (FGF1 or acidic FGF) is highly expressed in motor neurons. FGF‐1 is released from cells by oxidative stress, which might occur from SOD‐1 aberrant function in amyotrophic lateral sclerosis (ALS). Although FGF‐1 is known to be neuroprotective after spinal cord injury or axotomy, we found that FGF‐1 could activate spinal cord astrocytes in a manner that decreased motor neuron survival in co‐cultures. FGF‐1 induced accumulation of the FGF receptor 1 (FGFR1) in astrocyte nuclei and potently stimulated nerve growth factor (NGF) expression and secretion. The FGFR1 tyrosine kinase inhibitor PD166866 prevented these effects. Previously, we have shown that NGF secretion by reactive astrocytes induces motor neuron apoptosis through a p75NTR‐dependent mechanism. Embryonic motor neurons co‐cultured on the top of astrocytes exhibiting activated FGFR1 underwent apoptosis, which was prevented by PD166866 or by adding either anti‐NGF or anti‐p75NTR neutralizing antibodies. In the degenerating spinal cord of mice carrying the ALS mutation G93A of Cu, Zn superoxide dismutase, FGF‐1 was no longer localized only in the cytosol of motor neurons, while FGFR1 accumulated in the nuclei of reactive astrocytes. These results suggest that FGF‐1 released by oxidative stress from motor neurons might have a role in activating astrocytes, which could in turn initiate motor neuron apoptosis in ALS through a p75NTR‐dependent mechanism.
Increased phosphorylation and redistribution of NMDA receptors between synaptic lipid rafts and post‐synaptic densities following transient global ischemia in the rat brain
Authors: Besshoh Shintaro , Bawa Damanpreet , Teves Lucy , Wallace M. Christopher , Gurd James W.
Published: March 2005

Ischemia results in increased phosphorylation of NMDA receptors. To investigate the possible role of lipid rafts in this increase, lipid rafts and post‐synaptic densities (PSDs) were isolated by the extraction of rat brain synaptosomes with Triton X‐100 followed by sucrose density gradient centrifugation. Lipid rafts accounted for the majority of PSD‐95, whereas SAP102 was predominantly located in PSDs. Between 50 and 60% of NMDA receptors were associated with lipid rafts. Greater than 85–90% of Src and Fyn were present in lipid rafts, whereas Pyk2 was mainly associated with PSDs. Lipid rafts and PSDs were isolated from animals subjected to 15 min of global ischemia followed by 6 h of recovery. Ischemia did not affect the yield, density, flotillin‐1 or cholesterol content of lipid rafts. Following ischemia, the phosphorylation of NR1 by protein kinase C and tyrosine phosphorylation of NR2A and NR2B was increased in both lipid rafts and PSDs, with a greater increase in tyrosine phosphorylation occurring in the raft fraction. Following ischemia, NR1, NR2A and NR2B levels were elevated in PSDs and reduced in lipid rafts. The findings are consistent with a model involving close interaction between lipid rafts and PSDs and a role for lipid rafts in ischemia‐induced signaling pathways.
Activation of c‐Jun‐N‐terminal kinase is critical in mediating lipopolysaccharide‐induced changes in the rat hippocampus
Authors: Barry Claire E. , Nolan Yvonne , Clarke Rachael M. , Lynch Aileen , Lynch Marina A.
Published: March 2005

Lipopolysaccharide (LPS) exerts a myriad of effects in rat hippocampus; it increases the concentration of the proinflammatory cytokine, interleukin‐1β (IL‐1β), and signalling via the IL‐1 type I receptor (IL‐1RI) resulting in phosphorylation of the stress‐activated protein kinase, c‐jun‐N‐terminal kinase (JNK) and impairment in long‐term potentiation (LTP). This study was designed to establish whether activation of JNK is a pivotal event in mediating the effects of LPS in hippocampus and therefore LPS‐treated rats were injected intracerebroventricularly with saline, the JNK inhibitor D‐JNKI1, or with the anti‐inflammatory cytokine IL‐4, which antagonizes the effects of IL‐1β upstream of JNK activation. We report that IL‐4 blocked the LPS‐induced increase in IL‐1RI expression and associated increases in phosphorylation of JNK and c‐jun, whereas D‐JNKI1 inhibited the LPS‐induced phosphorylation of c‐jun. Both IL‐4 and D‐JNKI1 inhibited the increase in caspase‐3 staining which was associated with LPS treatment, and both abrogated the LPS‐induced inhibition of LTP in perforant path‐granule cell synapses. The data presented are consistent with the proposal that JNK activation, probably as a result of increased IL‐1RI activation, is a critical step in mediating the detrimental effects of LPS in hippocampus.
Protection by exogenous pyruvate through a mechanism related to monocarboxylate transporters against cell death induced by hydrogen peroxide in cultured rat cortical neurons
Authors: Nakamichi Noritaka , Kambe Yuki , Oikawa Hirotaka , Ogura Masato , Takano Katsura , Tamaki Keisuke , Inoue Maki , Hinoi Eiichi , Yoneda Yukio
Published: March 2005

In cortical neurons cultured for 3 or 9 days in vitro (DIV), exposure to hydrogen peroxide (H2O2) led to a marked decrease in cell viability in a concentration‐dependent manner at a concentration range of 10 µm to 1 mm irrespective of the duration between 6 and 24 h. However, H2O2 was more potent in decreasing cellular viability in cortical neurons cultured for 9 DIV than in those for 3 DIV. Pyruvate was effective in preventing the neuronal cell death at 1 mm even when added 1–3 h after the addition of H2O2. Semi‐quantitative RT–PCR and western blotting analyses revealed significantly higher expression of both mRNA and protein for a particular monocarboxylate transporter (MCT) in neurons cultured for 9 DIV than in those for 3 DIV. A specific inhibitor of MCT significantly attenuated the neuroprotection by pyruvate in neurons cultured for 9 DIV, without markedly affecting that in neurons cultured for 3 DIV. These results suggest that vulnerability to H2O2 may at least in part involve expression of particular MCT isoforms responsible for the bi‐directional transport of pyruvate across cell surfaces in cultured rat cortical neurons.
Nuclear Ca2+ and CaM kinase IV specify hormonal‐ and Notch‐responsiveness
Authors: Mckenzie Grahame J. , Stevenson Patrick , Ward George , Papadia Sofia , Bading Hilmar , Chawla Sangeeta , Privalsky Martin , Hardingham Giles E.
Published: March 2005

Many neuronal processes require gene activation by synaptically evoked Ca2+ transients. Ca2+‐dependent signal pathways activate some transcription factors outright, but here we report that such signals also potentiate the activation of nuclear receptors by their cognate hormone, and of CBF1 by Notch, transcription factors hitherto not thought to be Ca2+‐responsive. This potentiation is occluded by histone deacetylase inhibition, indicating a mechanism involving inactivation of co‐repressors associated with these transcription factors. Synaptic activity, acting via the nuclear Ca2+‐dependent activation of CaM kinase IV, triggers the disruption of subnuclear domains containing class II histone deacetylases (HDACs) and silencing mediator of retinoic acid and thyroid hormone receptors (SMRT), a broad‐specificity co‐repressor which represses nuclear hormone receptors and CBF1. The sequential loss of class II HDACs and SMRT from the subnuclear domains, followed by nuclear export, is associated with disruption of SMRT interaction with its target transcription factors and sensitization of these factors to their activating signal. Counterbalancing these changes, protein phosphatase 1 promotes nuclear localization of SMRT and inactivation of nuclear receptors and CBF1. Thus, the synaptically controlled kinase‐phosphatase balance of the neuron determines the efficacy of SMRT‐mediated repression and the signal‐responsiveness of a variety of transcription factors.
The role of tyrosine kinase‐mediated pathways in diabetes‐induced alterations in responsiveness of rat carotid artery
Authors: Yousif M. H. M. , Benter I. F. , Akhtar S.
Published: March 2005

1 G‐protein‐coupled receptor signalling, including transactivation of receptor tyrosine kinases (RTKs), has been implicated in vascular pathology. However, the role of specific RTKs in the development of diabetes‐induced cardiovascular complications is not known.

2 We investigated the ability of a chronic administration of genistein, a broad‐spectrum inhibitor of tyrosine kinases (TKs), AG1478, a specific inhibitor of epidermal growth factor receptor (EGFR) TK activity, and AG825, a specific inhibitor of Erb2, to modulate the altered vasoreactivity of isolated carotid artery ring segments to common vasoconstrictors and vasodilators in streptozotocin (STZ)‐induced diabetes.

3 In diabetic carotid artery, the vasoconstrictor responses induced by noradrenaline (NE), endothelin‐1 (ET‐1), and angiotensin II (Ang II), were significantly increased whereas vasodilator responses to carbachol and histamine were significantly reduced. Inhibition of TKs, EGFR or Erb2 pathway did not affect the body weight or agonist‐induced vasoconstrictor and vasodilator responses in the non‐diabetic control animals. However, inhibition of TKs by genistein, EGFR TK by AG1478 or Erb2 by AG825 treatment produced a significant normalization of the altered agonist‐induced vasoconstrictor responses without affecting blood glucose levels. Treatment with diadzein, an inactive analogue of genistein, did not affect the vasoconstrictor and vasodilator responses in the diabetic animals.

4 Treatment with genistein, AG1478 or AG825 resulted in a significant improvement in diabetes‐induced impairment in endothelium‐dependent relaxation to carbachol and histamine.

5 These data suggest that activation of TK‐mediated pathways, including EGFR TK signalling and Erb2 pathway, are involved in the development of diabetic vascular dysfunction in the carotid artery.
Cardiotoxicity of digitalis glycosides: roles of autonomic pathways, autacoids and ion channels
Authors: Demiryürek A. T. , Demiryürek S.
Published: March 2005

1 Cardiac glycosides have been used for centuries as therapeutic agents for the treatment of heart diaseases. In patients with heart failure, digoxin and the other glycosides exert their positive inotropic effect by inhibiting Na+–K+‐ATPase, thereby increasing intracellular sodium, which, in turn, inhibits the Na+/Ca2+ exchanger and increases intracellular calcium levels. As the therapeutic index of digitalis is narrow, arrhythmias are common problems in clinical practice. The mechanisms and mediators of these arrhythmias, however, are not completely understood.

2 The involvement of the sympathetic and parasympathetic nervous system in digitalis cardiac toxicity is reviewed.

3 Receptors, channels, exchange systems or other cellular components involved in digitalis‐induced cardiotoxicity are also reviewed.

4 Possible mediators of digitalis‐induced cardiac toxicity are discussed.

5 Management of digitalis toxicity in patients is summarized.

6 The determination of the possible mediators of digitalis‐induced cardiac toxicity will enhance our knowledge and lead to the development of new therapeutic strategies to treat these lethal arrhythmias.
Doxapram inhibits carotid sinus baroreceptors in rabbits
Authors: Osanai S. , Takahashi T. , Nakano H. , Kikuchi K.
Published: March 2005

1 To clarify the effects of doxapram on the baroreflex, we recorded carotid sinus nerve (CSN) activity in isolated and perfused carotid artery bifurcations of rabbits.

2 The CSN activity due to chemoreceptor stimulation was blocked by resection of the nerve branches from the carotid body. After the resection, the CSN activity was correlated to increase of carotid sinus (CS) pressure.

3 Administration of doxapram reduced the CSN activity originating from baroreceptors. The effect of doxapram on baroreceptors was dose dependent and reversible.

4 It is unlikely that doxapram altered CS wall mechanics because CS pressure did not change in the presence of the drug.

5 We conclude that doxapram acts on the cardiovascular system in part by inhibiting the negative feedback loop that originates in CS baroreceptors.