bluuebunny/crossref_metadata_2025 huggingface dataset:
Signal processing in local neuronal circuits based on activity-dependent noise and competition
Authors: Volman Vladislav , Levine Herbert
Published: July 2009

We study the characteristics of weak signal detection by a recurrent neuronal network with plastic synaptic coupling. It is shown that in the presence of an asynchronous component in synaptic transmission, the network acquires selectivity with respect to the frequency of weak periodic stimuli. For nonperiodic frequency-modulated stimuli, the response is quantified by the mutual information between input (signal) and output (network’s activity) and is optimized by synaptic depression. Introducing correlations in signal structure resulted in the decrease in input-output mutual information. Our results suggest that in neural systems with plastic connectivity, information is not merely carried passively by the signal; rather, the information content of the signal itself might determine the mode of its processing by a local neuronal circuit.
Kinetic damping of Alfvén eigenmodes in general tokamak geometry
Authors: Yu Limin , Fu Guo-yong , Sheng Zheng-Mao
Published: July 2009

A nonperturbative kinetic/magnetohydrodynamics eigenvalue code has been constructed for calculation of kinetic damping of shear Alfvén eigenmodes in general tokamak geometry with finite pressure. The model describes shear Alfvén waves with kinetic effects from thermal species including thermal ion finite Larmor radius effects and parallel electric field. An analytic formula for the radiative damping of reversed shear Alfvén eigenmodes is obtained for tokamak plasmas with reversed shear q profile. Numerical calculations reveal the existence of multiple kinetic reversed shear Alfvén eigenmodes (KRSAEs). It is found that the damping rate of the KRSAEs scales linearly with the thermal ion gyroradius. The damping rates are larger for modes with more peaks in the radial structures. These results are consistent with analytic expectation. The KRSAEs found here can be used to interpret the RSAEs frequency sweeping down observed sometime in the tokamak experiments.
Rare gas atomic number dependence of the hyperpolarizability for rare gas inserted fluorohydrides, HRgF (Rg=He, Ar, and Kr)
Authors: Liu Zhen-Bo , Li Zhi-Ru , Zuo Ming-Hui , Li Qing-Zhong , Ma Fang , Li Zong-Jun , Chen Guang-hui , Sun Chia-Chung
Published: July 2009

The three structures of rare gas inserted fluorohydrides HRgF (Rg=He, Ar, and Kr) with all real frequencies are obtained at the QCISD(T)/aug-cc-pVTZ level. The static first hyperpolarizabilities (β0) at the QCISD/aug-cc-pVQZ level are 8 a.u. (HF), 384 a.u. (HHeF), 737 a.u. (HArF), and 465 a.u. (HKrF). The β0 value remarkably increases by about 50–90 times from 8 a.u. (HF) to 384–737 a.u. (HRgF) due to the inserted rare gas (Rg). The Rg atomic number dependence of β0 for HRgF (Rg=He, Ar, and Kr) is found at the first time. The order of β0 is unmonotonic to be HHeFHKrF, but not monotonic (HHeF<HArF<HKrF). Why? The Rg atomic number dependence of β0 relates to both the geometric effect (expanded H⋯F distance by Rg) and the electronic effect of Rg. From HHeF to HArF and from HArF to HKrF, the preponderant effect on β0 is variational. From HHeF to HArF, the geometric effect is preponderant and the β0 value increases; from HArF to HKrF, the electronic effect of Rg is preponderant and the β0 value decreases. Thus, the rare gas atomic number dependence of β0 is unmonotonic. Furthermore, as the order of β0 is consistent with that of the difference between the ground and excited-state dipole moments (Δμ), the Δμ may be one mainly controlling factor of β0. The nature of H–Rg bond is also explored that special short H–He bond of 0.811 Å is only a half single bond due to its Wiberg bond index of 0.51, while the long H–Ar and H–Kr bonds are almost single bond with the Wiberg bond index of about 0.8.
Photocrosslinking of human telomeric G-quadruplex loops by
anti
cyclobutane thymine dimer formation
Authors: Su Dian G. T. , Fang Huafeng , Gross Michael L. , Taylor John-Stephen A.
Published: July 2009

The unusual structural forms of telomere DNA, which protect the ends of chromosomes during replication, may render it vulnerable to unprecedented photodamage, possibly involving nonadjacent bases that are made proximate by folding. The G-quadruplex for the human telomere sequence consisting of a repeating d(TTAGGG) is one unusual form. Tel22, d[AGGG(TTAGGG)
3
], forms a basket structure in the presence of Na
+
and may form multiple equilibrating structures in the presence of K
+
with hybrid-type structures predominating. UVB irradiation of d[AGGG(TTAGGG)
3
] in the presence of Na
+
results in a
cis,syn
thymine dimer between two adjacent Ts in a TTA loop and a mixture of nonadjacent
anti
thymine dimers between various loops. Irradiation in the presence of K
+
, however, produces, in addition to these same products, a large amount of specific
anti
thymine dimers formed between either T in loop 1 and the central T in loop 3. These latter species were not observed in the presence of Na
+
. Interloop-specific
anti
thymine dimers are incompatible with hybrid-type structures, but could arise from a chair or basket-type structure or from triplex intermediates involved in interconverting these structures. If these unique nonadjacent
anti
thymine dimer photoproducts also form in vivo, they would constitute a previously unrecognized type of DNA photodamage that may interfere with telomere replication and present a unique challenge to DNA repair. Furthermore, these unusual
anti
photoproducts may be used to establish the presence of G-quadruplex or quadruplex-like structures in vivo.
Optimized Gal4 genetics for permanent gene expression mapping in zebrafish
Authors: Distel Martin , Wullimann Mario F. , Köster Reinhard W.
Published: July 2009

Combinatorial genetics for conditional transgene activation allows studying gene function with temporal and tissue specific control like the Gal4-UAS system, which has enabled sophisticated genetic studies in
Drosophila
. Recently this system was adapted for zebrafish and promising applications have been introduced. Here, we report a systematic optimization of zebrafish Gal4-UAS genetics by establishing an optimized Gal4-activator (KalTA4). We provide quantitative data for KalTA4-mediated transgene activation in dependence of UAS copy numbers to allow for studying dosage effects of transgene expression. Employing a
Tol2
transposon-mediated KalTA4 enhancer trap screen biased for central nervous system expression, we present a collection of self-reporting red fluorescent KalTA4 activator strains. These strains reliably transactivate UAS-dependent transgenes and can be rendered homozygous. Furthermore, we have characterized the transactivation kinetics of tissue-specific KalTA4 activation, which led to the development of a self-maintaining effector strain “Kaloop.” This strain relates transient KalTA4 expression during embryogenesis via a KalTA4-mediated autoregulatory mechanism to live adult structures. We demonstrate its use by showing that the secondary octaval nucleus in the adult hindbrain is likely derived from
egr2b
-expressing cells in rhombomere 5 during stages of early embryogenesis. These data demonstrate prolonged and maintained expression by Kalooping, a technique that can be used for permanent spatiotemporal genetic fate mapping and targeted transgene expression in zebrafish.
The BRC repeats of human BRCA2 differentially regulate RAD51 binding on single- versus double-stranded DNA to stimulate strand exchange
Authors: Shivji Mahmud K. K. , Mukund Shreyas R. , Rajendra Eeson , Chen Shaoxia , Short Judith M. , Savill Jane , Klenerman David , Venkitaraman Ashok R.
Published: July 2009

The breast and ovarian cancer suppressor BRCA2 controls the enzyme RAD51 during homologous DNA recombination (HDR) to preserve genome stability. BRCA2 binds to RAD51 through 8 conserved BRC repeat motifs dispersed in an 1127-residue region (BRCA2
[BRC1–8]
). Here, we show that BRCA2
[BRC1–8]
exerts opposing effects on the binding of RAD51 to single-stranded (ss) versus double-stranded (ds) DNA substrates, enhancing strand exchange. BRCA2
[BRC1–8]
alters the electrophoretic mobility of RAD51 bound to an ssDNA substrate, accompanied by an increase in ssDNA-bound protein assemblies, revealed by electron microscopy. Single-molecule fluorescence spectroscopy shows that BRCA2
[BRC1–8]
promotes RAD51 loading onto ssDNA. In contrast, BRCA2
[BRC1–8]
has a different effect on RAD51 assembly on dsDNA; it suppresses and slows this process. When homologous ssDNA and dsDNA are both present, BRCA2
[BRC1–8]
stimulates strand exchange, with delayed RAD51 loading onto dsDNA accompanying the appearance of joint molecules representing recombination products. Collectively, our findings suggest that BRCA2
[BRC1–8]
targets RAD51 to ssDNA while inhibiting dsDNA binding and that these contrasting activities together bolster one another to stimulate HDR. Our work provides fresh insight into the mechanism of HDR in humans, and its regulation by the BRCA2 tumor suppressor.
Repression of α-synuclein expression and toxicity by microRNA-7
Authors: Junn Eunsung , Lee Kang-Woo , Jeong Byeong Seon , Chan Teresa W. , Im Joo-Young , Mouradian M. Maral
Published: July 2009

α-Synuclein is a key protein in Parkinson's disease (PD) because it accumulates as fibrillar aggregates in pathologic hallmark features in affected brain regions, most notably in nigral dopaminergic neurons. Intraneuronal levels of this protein appear critical in mediating its toxicity, because multiplication of its gene locus leads to autosomal dominant PD, and transgenic animal models overexpressing human α-synuclein manifest impaired function or decreased survival of dopaminergic neurons. Here, we show that microRNA-7 (miR-7), which is expressed mainly in neurons, represses α-synuclein protein levels through the 3′-untranslated region (UTR) of α-synuclein mRNA. Importantly, miR-7-induced down-regulation of α-synuclein protects cells against oxidative stress. Further, in the MPTP-induced neurotoxin model of PD in cultured cells and in mice, miR-7 expression decreases, possibly contributing to increased α-synuclein expression. These findings provide a mechanism by which α-synuclein levels are regulated in neurons, have implications for the pathogenesis of PD, and suggest miR-7 as a therapeutic target for PD and other α-synucleinopathies.
Translation and replication of hepatitis C virus genomic RNA depends on ancient cellular proteins that control mRNA fates
Authors: Scheller Nicoletta , Mina Leonardo Bruno , Galão Rui Pedro , Chari Ashwin , Giménez-Barcons Mireia , Noueiry Amine , Fischer Utz , Meyerhans Andreas , Díez Juana
Published: July 2009

Inevitably, viruses depend on host factors for their multiplication. Here, we show that hepatitis C virus (HCV) RNA translation and replication depends on Rck/p54, LSm1, and PatL1, which regulate the fate of cellular mRNAs from translation to degradation in the 5′-3′-deadenylation-dependent mRNA decay pathway. The requirement of these proteins for efficient HCV RNA translation was linked to the 5′ and 3′ untranslated regions (UTRs) of the viral genome. Furthermore, LSm1–7 complexes specifically interacted with essential
cis
-acting HCV RNA elements located in the UTRs. These results bridge HCV life cycle requirements and highly conserved host proteins of cellular mRNA decay. The previously described role of these proteins in the replication of 2 other positive-strand RNA viruses, the plant brome mosaic virus and the bacteriophage Qß, pinpoint a weak spot that may be exploited to generate broad-spectrum antiviral drugs.
Visuospatial Working Memory Deficits and Visual Pursuit Impairments are Not Directly Related in Schizophrenia
Authors: Cocchi Luca , Bosisio Francesca , Carter Olivia , Wood Stephen J. , Berchtold André , Conus Philippe , Orita Alina , Debbané Martin , Schenk Françoise
Published: July 2009

Objective: Patients with schizophrenia show deficits in visuospatial working memory and visual pursuit processes. It is currently unclear, however, whether both impairments are related to a common neuropathological origin. The purpose of the present study was therefore to examine the possible relations between the encoding and the discrimination of dynamic visuospatial stimuli in schizophrenia.

Method: Sixteen outpatients with schizophrenia and 16 control subjects were asked to encode complex disc displacements presented on a screen. After a delay, participants had to identify the previously presented disc trajectory from a choice of six static linear paths, among which were five incorrect paths. The precision of visual pursuit eye movements during the initial presentation of the dynamic stimulus was assessed. The fixations and scanning time in definite regions of the six paths presented during the discrimination phase were investigated.

Results: In comparison with controls, patients showed poorer task performance, reduced pursuit accuracy during incorrect trials and less time scanning the correct stimulus or the incorrect paths approximating its global structure. Patients also spent less time scanning the leftmost portion of the correct path even when making a correct choice. The accuracy of visual pursuit and head movements, however, was not correlated with task performance.

Conclusions: The present study provides direct support for the hypothesis that active integration of visuospatial information within working memory is deficient in schizophrenia. In contrast, a general impairment of oculomotor mechanisms involved in smooth pursuit did not appear to be directly related to lower visuospatial working memory performance in schizophrenia.
Internet Treatment for Social Phobia Reduces Comorbidity
Authors: Titov Nickolai , Gibson Matthew , Andrews Gavin , McEvoy Peter
Published: July 2009

Objective: Social phobia can be treated by brief Internet-based cognitive behaviour therapy (CBT). Most people with social phobia, however, meet criteria for another mental disorder; this comorbidity is associated with significant disability, and cases of comorbidity may be more difficult to treat. The present study examined the impact of the Shyness programme, an Internet-based treatment programme for social phobia, on comorbid symptoms of depression and generalized anxiety disorder.

Method: Data from three randomized controlled trials using the Shyness programme to treat social phobia were reanalysed. The 211 subjects, all of whom met DSM-IV criteria for social phobia, were divided into four groups: (i) social phobia only; (ii) social phobia with elevated symptoms of depression; (iii) social phobia with elevated symptoms of generalized anxiety; and (iv) social phobia with elevated symptoms of both generalized anxiety and depression. The improvement in social phobia, depression and anxiety following Internet-based treatment for social phobia was measured.

Results: Improvement in social phobia was seen in all groups, whether comorbid or not. Significant improvements in comorbid symptoms of depression and generalized anxiety occurred even though the treatment was focused on the social phobia.

Conclusions: Brief Internet-based CBT can reduce both the target disorder as well as comorbid symptoms. These findings are consistent with evidence that unified or transdiagnostic programmes may reduce the severity of comorbid disorders and symptoms, indicating an important direction for future research.
Suitability of Hydraulic Disk Brakes for Passive Actuation of Upper‐Extremity Rehabilitation Exoskeleton
Authors: Stienen Arno H. A. , Hekman Edsko E. G. , Schouten Alfred C. , van der Helm Frans C. T. , van der Kooij Herman
Published: July 2009

Passive, energy‐dissipating actuators are promising for force‐coordination training in stroke rehabilitation, as they are inherently safe and have a high torque‐to‐weight ratio. The goal of this study is to determine if hydraulic disk brakes are suitable to actuate an upper‐extremity exoskeleton, for application in rehabilitation settings. Passive actuation with friction brakes has direct implications for joint control. Braking is always opposite to the movement direction. During standstill, the measured torque is equal to the torque applied by the human. During rotations, it is equal to the brake torque. Actively assisting movement is not possible, nor are energy‐requiring virtual environments. The evaluated disk brake has a 20 Nm bandwidth (flat‐spectrum, multi‐sine) of 10 Hz; sufficient for torques required for conventional therapy and simple, passive virtual environments. The maximum static output torque is 120 Nm, sufficient for isometric training of the upper extremity. The minimal impedance is close zero, with only the inertia of the device felt. In conclusion, hydraulic disk brakes are suitable for rehabilitation devices.
Influence of Attachment Pressure and Kinematic Configuration on pHRI with Wearable Robots
Authors: Schiele André , van der Helm Frans C. T.
Published: July 2009

The goal of this paper is to show the influence of exoskeleton attachment, such as the pressure on the fixation cuffs and alignment of the robot joint to the human joint, on subjective and objective performance metrics (i.e. comfort, mental load, interface forces, tracking error and available workspace) during a typical physical human‐robot interaction (pHRI) experiment. A mathematical model of a single degree of freedom interaction between humans and a wearable robot is presented and used to explain the causes and characteristics of interface forces between the two. The pHRI model parameters (real joint offsets, attachment stiffness) are estimated from experimental interface force measurements acquired during tests with 14 subjects. Insights gained by the model allow optimisation of the exoskeleton kinematics. This paper shows that offsets of more than ±10 cm exist between human and robot axes of rotation, even if a well‐designed exoskeleton is aligned properly before motion. Such offsets can create interface loads of up to 200 N and 1.5 Nm in the absence of actuation. The optimal attachment pressure is determined to be 20 mmHg and the attachment stiffness is about 300 N/m. Inclusion of passive compensation joints in the exoskeleton is shown to lower the interaction forces significantly, which enables a more ergonomic pHRI.
A Force‐Feedback Exoskeleton for Upper‐Limb Rehabilitation in Virtual Reality
Authors: Frisoli Antonio , Salsedo Fabio , Bergamasco Massimo , Rossi Bruno , Carboncini Maria C.
Published: July 2009

This paper presents the design and the clinical validation of an upper‐limb force‐feedback exoskeleton, the L‐EXOS, for robotic‐assisted rehabilitation in virtual reality (VR). The L‐EXOS is a five degrees of freedom exoskeleton with a wearable structure and anthropomorphic workspace that can cover the full range of motion of human arm. A specific VR application focused on the reaching task was developed and evaluated on a group of eight post‐stroke patients, to assess the efficacy of the system for the rehabilitation of upper limb. The evaluation showed a significant reduction of the performance error in the reaching task (paired t‐test, p < 0.02)
A new method for revealing correlated mutations under the structural and functional constraints in proteins
Authors: Lee Byung-Chul , Kim Dongsup
Published: July 2009

Motivation: Diverse studies have shown that correlated mutation (CM) is an important molecular evolutionary process alongside conservation. However, attempts to find the residue pairs that co-evolve under the structural and/or functional constraints are complicated by the fact that a large portion of covariance signals found in multiple sequence alignments arise from correlations due to common ancestry and stochastic noise.

Results: Assuming that the background noise can be estimated from the coevolutionary relationships among residues, we propose a new measure for background noise called the normalized coevolutionary pattern similarity (NCPS) score. By subtracting NCPS scores from raw CM scores and combining the results with an entropy factor, we show that these new scores effectively reduce the background noise. To test the effectiveness of this method in detecting residue pairs coevolving under the structural constraints, two independent test sets were performed, showing that this new method performs better than the most accurate method currently available. In addition, we also applied our method to double mutant cycle experiments and protein–protein interactions. Although more rigorous tests are required, we obtained promising results that our method tended to explain those data better than other methods. These results suggest that the new noise-reduced CM scores developed in this study can be a valuable tool for the study of correlated mutations under the structural and/or functional constraints in proteins.

Contact:  kds@kaist.ac.kr

Availability:  http://pbil.kaist.ac.kr

Supplementary information:  Supplementary data are available at Bioinformatics online.
History, a Useful “Science” for Management? A Response
Authors: Popp Andrew
Published: July 2009

In response to Eric Godelier's call for a partnership between business history and the management sciences I argue for a vision of business history as history. Whilst acknowledging the institutional and intellectual pressures to which the discipline is subject I argue such a turn is important for the continued health of the field. Such a turn will, however, also require engaging with fundamental questions of epsitemology.
Activated cell survival cascade protects cardiomyocytes from cell death in Tako‐Tsubo cardiomyopathy
Authors: Nef Holger M. , Möllmann Helge , Hilpert Pirmin , Troidl Christian , Voss Sandra , Rolf Andreas , Behrens Christopher B. , Weber Michael , Hamm Christian W. , Elsässer Albrecht
Published: July 2009

Aims

Tako‐Tsubo cardiomyopathy (TTC) is characterized by rapid regeneration of contractile dysfunction. From recent studies it is known that excessive catecholamine levels due to emotional or physical stress might play a central role. After sympathetic activation, the PIK3/AKT pathway is a key regulator of many cellular responses, including cytoprotective effects. Thus, the purpose of this study was to investigate whether the PIK3/AKT pathway plays a pivotal role in TTC.

Methods and results

A total of 16 consecutive patients diagnosed with TTC were studied. Left ventricular biopsies were taken during the acute phase and after functional recovery. Specimens were examined by quantitative RT–PCR and western blotting. Representative genes of the PI3K/AKT pathway (PIK3‐R1, PTEN, GSK3β, mTOR, PP2A, eIF4E) were compared with left ventricular controls from non‐transplanted healthy hearts. PI3K expression was increased during the acute phase and after functional recovery. AKT protein levels were unaltered, but phosphorylation significantly increased during the acute phase. Both PTEN (PI3K antagonist) and PP2 (unspecific phosphatase) were down‐regulated. Phosphorylation of the PI3K/AKT downstream target mTOR was increased, while expression of both GSK3 isoforms was decreased. The Bax/Bcl2 ratio was increased in the acute and recovery phases.

Conclusion

PI3K/AKT signalling is activated in TTC. This activated cell survival cascade might protect cardiomyocytes from cell death and also contribute to rapid regeneration in TTC.
Correction for Shakarad
et al.
, Faster development does not lead to correlated evolution of greater pre-adult competitive ability in
Drosophila melanogaster
Authors: Shakarad Mallikarjun , Prasad N. G. , Gokhale Kaustubh , Gadagkar Vikram , Rajamani M. , Joshi Amitabh
Published: July 2009

Correction for ‘Faster development does not lead to correlated evolution of greater pre-adult competitive ability in
Drosophila melanogaster
’ by Mallikarjun Shakarad, N. G. Prasad, Kaustubh Gokhale, Vikram Gadagkar, M. Rajamani and Amitabh Joshi (Biol. Lett.
1
, 91–94.
(doi:
10.1098/2004.0261
)).

On p. 91, the Digital Object Identifier should be 10.1098/rsbl.2004.0261.
A model of mixed signals with applications to countersignalling
Authors: Araujo Aloisio , Gottlieb Daniel , Moreira Humberto
Published: July 2009

We develop a job‐market signalling model where signals convey two pieces of information. This model is employed to study countersignalling (signals nonmonotonic in ability) and the GED exam. A result of the model is that countersignalling is more likely to occur in jobs that require a combination of skills that differs from the combination used in the schooling process. The model also produces testable implications consistent with evidence on the GED: (i) it signals both high cognitive and low noncognitive skills and (ii) it does not affect wages.
Moonlighting: public service and private practice
Authors: Biglaiser Gary , Albert Ma Ching‐to
Published: July 2009

We study job incentives in moonlighting, when public‐service physicians may refer patients to their private practices. Some doctors in the public system are dedicated, and behave sincerely, but others—the moonlighters—are utility maximizers. Allowing moonlighting always enhances aggregate consumer welfare, but equilibrium public‐care quality may increase or decrease; if quality increases, moonlighting improves each consumer's expected utility. Unregulated moonlighting may reduce consumer welfare as a result of adverse behavioral reactions, such as moonlighters shirking more and dedicated doctors abandoning their sincere behavior. Price regulation in the private market limits such adverse behaviors in the public system and improves consumer welfare.
Density‐dependent growth rate in an age‐structured population: a field study on stream‐dwelling brown troutSalmo trutta
Authors: Kaspersson R. , Höjesjö J.
Published: July 2009

A field experiment during autumn, winter and spring was performed in a small stream on the west coast of Sweden, aiming to examine the direct and indirect consequences of density‐dependent intercohort competition in brown troutSalmo trutta. Individual growth rate, recapture rate and site fidelity were used as response variables in the young‐of‐the‐year (YOY) age class, experiencing two different treatments: presence or absence of yearlings and over‐yearlings (age ≥ 1+ year individuals). YOY individuals in stream sections with reduced density of age ≥ 1+ year individuals grew significantly faster than individuals experiencing natural cohort structure. In the latter, growth rate was negatively correlated with density and biomass of age ≥ 1+ year individuals, which may induce indirect effects on year‐class strength through, for example, reduced fecundity and survival. Movement of YOY individuals and turnover rate (i.e.proportion of untagged individuals) were used to demonstrate potential effects of intercohort competition on site fidelity. While YOY movement was remarkably restricted (83% recaptured within 50 m from the release points), turnover rate was higher in sections with reduced density of age ≥1+ year individuals, suggesting that reduced density of age ≥1+ year individuals may have released favourable microhabitats.
Investigation of first year biotic and abiotic influences on the recruitment of pikeEsox luciusover 48 years in Windermere, U.K.
Authors: Paxton C. G. M. , Winfield I. J. , Fletcher J. M. , George D. G. , Hewitt D. P.
Published: July 2009

Estimated pikeEsox luciusrecruitment varied by a factor of 16 for females from 1944 to 1991 and by a factor of 27 for males from 1943 to 1990 in Windermere, a temperate, mesotrophic U.K. lake. No significant stock–recruitment relationships were found, but analysis with general additive models (GAMs) revealed that early autumnal water temperature, strength and direction of the North Atlantic Oscillation displacement (corresponding to different climatic conditions in winter) and zooplankton abundance but above all, late summer water temperature were important explanatory variables over the entire time series. Female recruitment was also influenced by young‐of‐the‐year winter temperature. There was no evidence that perchPerca fluviatilisyear‐class strength, lake level or the summer position of the Gulf Stream influenced recruitment. The fitted models explained up toc.65% of the overall observed variation between years.
Effects of food type on diel behaviours of common carp Cyprinus carpio in simulated aquaculture pond conditions
Authors: Rahman M. M. , Meyer C. G.
Published: July 2009

In order to better understand behaviour patterns of common carp Cyprinus carpio in aquaculture ponds, their diel grazing, swimming, resting and schooling behaviours were observed in six 1 m2 tanks under simulated pond conditions. Each tank was fertilized to stimulate natural food production before starting experiments, and then stocked with three C. carpio. Fish behaviours were compared among three treatments: (1) tanks with plankton only, (2) tanks with plankton and benthic macroinvertebrates and (3) tanks with plankton, benthic macroinvertebrates and artificial feed. Overall C. carpio grazed more frequently during daytime than at night and exhibited the reverse pattern for non‐feeding swimming behaviour. A significant negative relationship (r2 = 0·99, P < 0·01, n = 48) was observed between total per cent grazing time and total per cent swimming time. Fish dispersed to graze individually during daytime but schooled at night and did not display any agonistic behaviours. Diel variations in the vertical swimming behaviour of C. carpio were related to food types available. In tanks containing plankton only, fish grazed in the water column, whereas when benthic macroinvertebrates were present, they spent more time near the tank bottom. Resting behaviour was only seen in tanks with artificial feed and even then was rare (2–5% of total time). Results suggest that C. carpio growth and feed utilization efficiency in semi‐intensive aquaculture systems could be optimized by using a combination of plankton, benthic macroinvertebrates and artificial feed, and feeding fish twice per day (at c. 0730 and c. 1630 hours).
Density‐independent growth of floodplain river channel catfish Ictalurus punctatus
Authors: Shephard S. , Jackson D. C.
Published: July 2009

This study investigated the relative influence of biotic and abiotic factors on the growth of channel catfish Ictalurus punctatus in seven Mississippi floodplain rivers. The results indicate that growth was density‐independent, being defined largely by abiotic conditions.
Assessment of reproductive potential in multiple‐spawning fish with indeterminate fecundity: a case study of yellow sea bream Dentex hypselosomus in the East China Sea
Authors: Yoda M. , Yoneda M.
Published: July 2009

This study examined the spawning season, spawning frequency and batch fecundity of yellow sea bream Dentex hypselosomus in the East China Sea to reassess the previously reported reproductive characteristics of the species. Time‐course sampling showed that this species had a diurnal ovarian maturation rhythm. Late tertiary yolk‐stage oocytes appeared 2 days before spawning, starting the process of germinal vesicle movement and breakdown. On the day of spawning, ovulation and subsequent spawning occurred in the early morning (0400–0800 hours). Postovulatory follicles disappeared from the ovaries within c. 24 h of ovulation. Seasonal changes in the ovarian conditions indicated that this species spawned more or less throughout the year, with the peak ranging from spring to autumn. The compositions of the developing oocytes and degenerating postovulatory follicles in the ovaries suggested that most females spawned repeatedly over 2 to 3 consecutive days during the peak of the spawning season. Somatic body condition did not have a significant effect on batch fecundity, but there was a significant relationship between batch fecundity and fork length according to spawning status. Females spawning on consecutive days were more fecund than those spawning every other day. The findings show that this species has much greater reproductive potential than previously estimated.
Prospective study of the effects of concomitant medications on thiopurine metabolism in inflammatory bowel disease
Authors: DAPERNO M. , SOSTEGNI R. , CANAPARO R. , SERPE L. , LAVAGNA A. , CROCELLÀ L. , CASTAGNO F. , VERNETTO A. , RIGAZIO C. , ERCOLE E. , D’ANTICO S. , PERA A. , ZARA G. , ROCCA R.
Published: July 2009

Aliment Pharmacol Ther 30, 843–853

Background  Thiopurines are increasingly used in the treatment of inflammatory bowel disease (IBD), being the most common immunosuppressive therapy; however, potentially harmful interactions between thiopurines and other drugs (especially 5‐aminosalicylic acid, 5‐ASA) were described.

Aim  To explore potential interactions between thiopurines and concomitant medications.

Methods  A total of 183 consecutive IBD patients were enrolled. Clinical characteristics and concomitant medications were recorded. Thiopurine metabolism was analysed with thiopurine S‐methyl transferase (TPMT) genetic variants and enzyme activity assays. Comparisons were carried out with stratification of patients according to clinical characteristics and active treatments.

Results  Based on TPMT genetics, 95% IBD patients were wild‐type homozygous, the remaining being heterozygous. Median TPMT activity was 24.9 U/Hgb g (IQR 20.7–29.5). No difference in TPMT activity was noted according to 5‐ASA exposure. IBD patients on thiopurines had higher TPMT activity levels, but no dose‐effect was evident. No difference in TPMT activity was observed in 41 (63%) patients co‐treated with 5‐ASA. In patients on active thiopurines also, 6‐TGN and 6‐MMP levels were evaluated and no significant difference was observed based on co‐medication. TPMT activity was independently associated only with thiopurines dose (P = 0.016).

Conclusions  Our data suggest the absence of significant interactions between thiopurines and 5‐ASA.
The GABAB receptor agonist AZD9343 inhibits transient lower oesophageal sphincter relaxations and acid reflux in healthy volunteers: a phase I study
Authors: BEAUMONT H. , SMOUT A. , AANEN M. , RYDHOLM H. , LEI A. , LEHMANN A. , RUTH M. , BOECKXSTAENS G.
Published: July 2009

Background  Transient lower oesophageal sphincter relaxations (TLESRs) represent an interesting target for the treatment of gastro‐oesophageal reflux. Baclofen reduces TLESRs and reflux episodes, but is not optimal for clinical application because of its central side effects. Therefore, new agents are required.

Aim  To study the effect of AZD9343, a new selective GABAB receptor agonist, in healthy volunteers.

Methods  A total of 27 subjects participated in a placebo‐controlled, randomized, two‐centre phase I study. Subjects underwent oesophageal manometry and pH‐metry for 3 h postprandially. Before meal ingestion, a single oral dose of placebo, 60 and 320 mg AZD9343 or 40 mg baclofen was given on four separate days.

Results  Somnolence was reported after 320 mg AZD9343 and baclofen. Reversible short‐lasting paraesthesia was reported after AZD9343. AZD9343 320 mg and baclofen significantly reduced the number of TLESRs with 32% and 40% respectively. Acid reflux was significantly decreased by AZD9343 and baclofen. Like baclofen, AZD9343 increased LES pressure before meal intake. AZD9343 320 mg and baclofen significantly reduced the swallowing rate.

Conclusions  Like baclofen, AZD9343 dose‐dependently decreases the number of TLESRs and acid reflux episodes, increases LES pressure and reduces swallowing, extending the concept that GABAB agonists are potent reflux inhibitors. However, discovery of analogues with an improved side effect profile is warranted.
Postoperative development of aspirin resistance following coronary artery bypass
Authors: Kempfert J. , Anger K. , Rastan A. , Krabbes S. , Lehmann S. , Garbade J. , Sauer M. , Walther T. , Dhein S. , Mohr F. W.
Published: July 2009

Background  Aspirin therapy is known to substantially reduce mortality and the rate of ischaemic complications after coronary artery bypass grafting (CABG). Rates of perioperative aspirin resistance cited in the literature are up to 50% and could be influenced by extracorporeal circulation. Thus, aspirin resistance after CABG may have a significant clinical relevance.

Materials and methods  In 59 patients undergoing CABG (on‐pump, off‐pump and combined procedures) aspirin resistance was investigated by arachidonic acid induced platelet aggregometry. Clinical relevance was assessed with 12‐month follow up.

Results  Two types of resistance were observed: A preoperative resistance (despite oral aspirin or in vitro addition) was present in 29% and a postoperative developing type was seen in 49% resulting in only 22% of patients with a ‘normal’ reaction to aspirin. If patients were already on oral aspirin at admission, the rate of resistance was significantly reduced. Off‐pump surgery or pump‐times exceeding 120 min had no significant impact on resistance. During the 12‐month follow up (98·3%), there were three deaths (one stroke, one intestinal ischaemia, one mediastinitis after postoperative delirium) in patients with the perioperative resistance and none in other patients (P = 0·345). In none of those patients who presented with perioperative aspirin resistance, could this aspirin resistance be demonstrated when tested again after 12 months?

Conclusions  Aspirin resistance is a transient phenomenon present in the majority of patients undergoing CABG. The three deaths in the resistant group may – although not statistically significant – indicate the possibility of a worse outcome for patients with aspirin resistance.
Recording and controlling the 4D light field in a microscope using microlens arrays
Authors: LEVOY M. , ZHANG Z. , MCDOWALL I.
Published: July 2009

By inserting a microlens array at the intermediate image plane of an optical microscope, one can record four‐dimensional light fields of biological specimens in a single snapshot. Unlike a conventional photograph, light fields permit manipulation of viewpoint and focus after the snapshot has been taken, subject to the resolution of the camera and the diffraction limit of the optical system. By inserting a second microlens array and video projector into the microscope's illumination path, one can control the incident light field falling on the specimen in a similar way. In this paper, we describe a prototype system we have built that implements these ideas, and we demonstrate two applications for it: simulating exotic microscope illumination modalities and correcting for optical aberrations digitally.
Overlapping nuclei segmentation based on Bayesian networks and stepwise merging strategy
Authors: JEONG M.‐R. , KO B.C. , NAM J.‐Y.
Published: July 2009

This paper presents a new approach to the segmentation of fluorescencein situhybridization images. First, to segment the cell nuclei from the background, a threshold is estimated using a Gaussian mixture model and maximizing the likelihood function of the grey values for the cell images. After the nuclei segmentation, the overlapping and isolated nuclei are classified to facilitate a more accurate nuclei analysis. To do this, the morphological features of the nuclei, such their compactness, smoothness and moments, are extracted from training data to generate three probability distribution functions that are then applied to a Bayesian network as evidence. Following the nuclei classification, the overlapping nuclei are segmented into isolated nuclei using an intensity gradient transform and watershed algorithm. A new stepwise merging strategy is also proposed to merge fragments into a major nucleus. Experimental results using fluorescencein situhybridization images confirm that the proposed system produced better segmentation results when compared to previous methods, because of the nuclei classification before separating the overlapping nuclei.
Imaging of endodontic biofilms by combined microscopy (FISH/cLSM – SEM)
Authors: SCHAUDINN C. , CARR G. , GORUR A. , JARAMILLO D. , COSTERTON J.W. , WEBSTER P.
Published: July 2009

Scanning electron microscopy is a useful imaging approach for the visualization of bacterial biofilms in their natural environments including their medical and dental habitats, because it allows for the exploration of large surfaces with excellent resolution of topographic features. Most biofilms in nature, however, are embedded in a thick layer of extracellular matrix that prevents a clear identification of individual bacteria by scanning electron microscopy. The use of confocal laser scanning microscopy on the other hand in combination with fluorescence in situ hybridization enables the visualization of matrix embedded bacteria in multi‐layered biofilms. In our study, fluorescence in situ hybridization/confocal laser scanning microscopy and scanning electron microscopy were applied to visualize bacterial biofilm in endodontic root canals. The resulting fluorescence in situ hybridization /confocal laser scanning microscopy and scanning electron microscopy and pictures were subsequently combined into one single image to provide high‐resolution information on the location of hidden bacteria. The combined use of scanning electron microscopy and fluorescence in situ hybridization / confocal laser scanning microscopy has the potential to overcome the limits of each single technique.
Internal kinematics of the tongue in relation to muscle activity and jaw movement in the pig
Authors: LIU Z.‐J. , SHCHERBATYY V. , KAYALIOGLU M. , SEIFI A.
Published: July 2009

Summary  To explore the coordinative characteristics of tongue deformation, muscle activity and jaw movement during feeding, six ultrasonic crystals were implanted into the tongue body of ten 12‐week‐old Yucatan minipigs 1 week before the recording. These crystals formed a wedge‐shaped configuration to allow recording dimensional changes in lengths, anterior and posterior widths and posterior thicknesses of the tongue body during feeding. Wire electromyographic activities (EMG) of superior and inferior longitudinalis, verticalis/transversus, genioglossus, styloglossus, masseter and digastricus and jaw movements were recorded simultaneously. Signals from these three sources were synchronized for real‐time analyses. The results indicate: (i) dimensional changes were stereotypical in relation to each cycle of all three feeding behaviours; (ii) during chewing, expansion of tongue widths mainly occurred in the occlusal phase of jaw movement and was less coupled with the activity of tongue muscles, but the expansions of length and thickness were seen in the opening and closing phases and were better coupled with the activity of tongue muscles (P < 0·05); (iii) ingestion was characterized by the two‐phased jaw opening, early expansion of anterior width prior to the occlusal phase and strong associations between tongue deformation and muscle activity; (iv) during drinking, the duration of the opening and closing phases was significantly prolonged (P < 0·01), the durations of tongue widening and lengthening were significantly shortened (P < 0·05) and anterior widening was predominant in the opening rather than in the closing or occlusal phases as compared with chewing and ingestion; and (v) the intrinsic tongue muscles did not show more or stronger correlations with the tongue deformation than did the extrinsic tongue muscles. These results suggest that (i) regional widening, lengthening and thickening of the tongue body occurs sequentially in relation to jaw movement phases, but the initiation of tongue dimensional expansions does not correspond with the activation of tongue muscles simultaneously; (ii) there is a better coupling between tongue deformations and tongue muscle activations in the sagittal (lengthening and thickening) than the transverse (widening) planes; and (iii) the patterns and ranges of tongue deformation and their relations to muscle activity and jaw movement are task‐specific and the expansion magnitudes of tongue deformation does not have closer correlations with the amount of EMG activity in the intrinsic than the extrinsic tongue or jaw muscles.
BRIEF REPORT: Association between MTHFR 677C‐T polymorphism and alcohol dependence according to Lesch and Babor typology
Authors: Benyamina Amine , Saffroy Raphaël , Blecha Lisa , Pham Patrick , Karila Laurent , Debuire Brigitte , Lemoine Antoinette , Reynaud Michel
Published: July 2009

Prior studies have associated 677C‐T Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with decreased enzymatic activity and modified homocysteine regulation. This study determines and compares MTHFR 677C‐T distribution and examines its consequences on homocysteine metabolism and alcohol dependence in alcoholic patients classified according to the Babor and Lesch typologies. MTHFR TT genotype was more prevalent in AD patients with milder alcohol dependence (Babor type A) and with Lesch type 3, associated with depression. MTHFR TT was also associated with hyperhomocysteinemia. Determining MTHFR 677C‐T genotype, folate and vitamin B12 levels could assist physicians in identifying type 3 patients and improve addictions management.
CLC– a novel susceptibility gene for allergic rhinitis?
Authors: Bryborn M. , Halldén C. , Säll T. , Cardell L. O.
Published: July 2009

To cite this article:Bryborn M, Halldén C, Säll T, Cardell LO.CLC– a novel susceptibility gene for allergic rhinitis?.Allergy2010;65: 220–228.

Background: Studies of the nasal lavage fluid proteome have previously identified proteins differently expressed in patients with symptomatic allergic rhinitis, e.g. S100A7, prolactin‐inducible protein (PIP), wingless‐type MMTV integration site family, member 2B (WNT2B), Charcot‐Leyden crystal protein (CLC) and palate lung nasal epithelial clone (PLUNC). The aim of the present study was to investigate if genetic variation associated with allergic rhinitis can be found in these genes.

Methods: Peripheral blood was collected from 251 patients with birch and/or grass pollen‐induced allergic rhinitis and 386 nonatopic healthy controls. A total of 39 single nucleotide polymorphisms (SNPs) distributed over the genesPIP,WNT2B,CLCandPLUNCwere selected from dbSNP, genotyped and investigated for associations with allergic rhinitis. Twelve additional SNPs were subsequently analysed forCLC.

Results: All 22 investigated SNPs inCLCwere polymorphic. Ten SNPs yielded significant differences between cases and controls with respect to genotype frequencies. Homozygotes for the minor allele were more common in allergic individuals compared to healthy controls. The minor alleles of these SNPs were all located on the same haplotype. Furthermore, homozygotes for the minor allele of two of the promoter SNPs had higher average scores for birch in skin prick test. In contrast, for seven SNPs within the gene, heterozygotes and homozygotes for the major allele had higher average scores for grass. None of the other three genes showed association.

Conclusion: Genetic variation inCLCwas found to be associated with allergic rhinitis. The pattern of variation is compatible with a recessive inheritance model and the previously observed altered protein levels detected in patients with allergic rhinitis.