bluuebunny/crossref_metadata_2025_split huggingface dataset:
Search and the Aging Mind: The Promise and Limits of the Cognitive Control Hypothesis of Age Differences in Search
Authors: Mata Rui , von Helversen Bettina 
Published: March 2015

AbstractSearch is a prerequisite for successful performance in a broad range of tasks ranging from making decisions between consumer goods to memory retrieval. How does aging impact search processes in such disparate situations? Aging is associated with structural and neuromodulatory brain changes that underlie cognitive control processes, which in turn have been proposed as a domain‐general mechanism controlling search in external environments as well as memory. We review the aging literature to evaluate the cognitive control hypothesis that suggests that age‐related change in cognitive control underlies age differences in both external and internal search. We also consider the limits of the cognitive control hypothesis and propose additional mechanisms such as changes in strategy use and affect that may be necessary to understand how aging affects search.
Exercise training and return to a well‐balanced diet activate the neuregulin 1/ErbB pathway in skeletal muscle of obese rats
Authors: Ennequin Gaël , Boisseau Nathalie , Caillaud Kevin , Chavanelle Vivien , Gerbaix Maude , Metz Lore , Etienne Monique , Walrand Stéphane , Masgrau Aurélie , Guillet Christelle , Courteix Daniel , Niu Airu , Li Yi‐Ping , Capel Fréderic , Sirvent Pascal 
Published: March 2015

Key points
Some studies suggest that neuregulin 1 (NRG1) could be involved in the regulation of skeletal muscle energy metabolism in rodents.
Here we assessed whether unbalanced diet is associated with alterations of the NRG1 signalling pathway and whether exercise and diet might restore NRG1 signalling in skeletal muscle of obese rats.
We show that diet‐induced obesity does not impair NRG1 signalling in rat skeletal muscle.
We also report that endurance training and a well‐balanced diet activate the NRG1 signalling in skeletal muscle of obese rats, possibly via a new mechanism mediated by the protease ADAM17.
These results suggest that some beneficial effects of physical activity and diet in obese rats could be partly explained by stimulation of the NRG1 signalling pathway.
AbstractSome studies suggest that the signalling pathway of neuregulin 1 (NRG1), a protein involved in the regulation of skeletal muscle metabolism, could be altered by nutritional and exercise interventions. We hypothesized that diet‐induced obesity could lead to alterations of the NRG1 signalling pathway and that chronic exercise could improve NRG1 signalling in rat skeletal muscle. To test this hypothesis, male Wistar rats received a high fat/high sucrose (HF/HS) diet for 16 weeks. At the end of this period, NRG1 and ErbB expression/activity in skeletal muscle was assessed. The obese rats then continued the HF/HS diet or were switched to a well‐balanced diet. Moreover, in both groups, half of the animals also performed low intensity treadmill exercise training. After another 8 weeks, NRG1 and ErbB expression/activity in skeletal muscle were tested again. The 16 week HF/HS diet induced obesity, but did not significantly affect the NRG1/ErbB signalling pathway in rat skeletal muscle. Conversely, after the switch to a well‐balanced diet, NRG1 cleavage ratio and ErbB4 amount were increased. Chronic exercise training also promoted NRG1 cleavage, resulting in increased ErbB4 phosphorylation. This result was associated with increased protein expression and phosphorylation ratio of the metalloprotease ADAM17, which is involved in NRG1 shedding. Similarly, in vitro stretch‐induced activation of ADAM17 in rat myoblasts induced NRG1 cleavage and ErbB4 activation. These results show that low intensity endurance training and well‐balanced diet activate the NRG1‐ErbB4 pathway, possibly via the metalloprotease ADAM17, in skeletal muscle of diet‐induced obese rats.
State‐dependent control of breathing by the retrotrapezoid nucleus
Authors: Burke Peter G.R. , Kanbar Roy , Basting Tyler M. , Hodges Walter M. , Viar Kenneth E. , Stornetta Ruth L. , Guyenet Patrice G. 
Published: March 2015

Key points
This study explores the state dependence of the hypercapnic ventilatory reflex (HCVR). We simulated an instantaneous increase or decrease of central chemoreceptor activity by activating or inhibiting the retrotrapezoid nucleus (RTN) by optogenetics in conscious rats.
During quiet wake or non‐REM sleep, hypercapnia increased both breathing frequency (fR) and tidal volume (VT) whereas, in REM sleep, hypercapnia increased VT exclusively.
Optogenetic inhibition of RTN reduced VT in all sleep–wake states, but reduced fR only during quiet wake and non‐REM sleep. RTN stimulation always increased VT but raised fR only in quiet wake and non‐REM sleep.
Phasic RTN stimulation produced active expiration and reduced early expiratory airflow (i.e. increased upper airway resistance) only during wake.
We conclude that the HCVR is highly state‐dependent. The HCVR is reduced during REM sleep because fR is no longer under chemoreceptor control and thus could explain why central sleep apnoea is less frequent in REM sleep.
AbstractBreathing has different characteristics during quiet wake, non‐REM or REM sleep, including variable dependence on . We investigated whether the retrotrapezoid nucleus (RTN), a proton‐sensitive structure that mediates a large portion of the hypercapnic ventilatory reflex, regulates breathing differently during sleep vs. wake. Electroencephalogram, neck electromyogram, blood pressure, respiratory frequency (fR) and tidal volume (VT) were recorded in 28 conscious adult male Sprague–Dawley rats. Optogenetic stimulation of RTN with channelrhodopsin‐2, or inhibition with archaerhodopsin, simulated an instantaneous increase or decrease of central chemoreceptor activity. Both opsins were delivered with PRSX8‐promoter‐containing lentiviral vectors. RTN and catecholaminergic neurons were transduced. During quiet wake or non‐REM sleep, hypercapnia (3 or 6% ) increased both fR and VT whereas, in REM sleep, hypercapnia increased VT exclusively. RTN inhibition always reduced VT but reduced fR only during quiet wake and non‐REM sleep. RTN stimulation always increased VT but raised fR only in quiet wake and non‐REM sleep. Blood pressure was unaffected by either stimulation or inhibition. Except in REM sleep, phasic RTN stimulation entrained and shortened the breathing cycle by selectively shortening the post‐inspiratory phase. Phasic stimulation also produced active expiration and reduced early expiratory airflow but only during wake. VT is always regulated by RTN and CO2 but fR is regulated by CO2 and RTN only when the brainstem pattern generator is in autorhythmic mode (anaesthesia, non‐REM sleep, quiet wake). The reduced contribution of RTN to breathing during REM sleep could explain why certain central apnoeas are less frequent during this sleep stage.
Chloride transporters and receptor‐mediated endocytosis in the renal proximal tubule
Authors: Devuyst Olivier , Luciani Alessandro 
Published: March 2015

Key points
The reabsorptive activity of renal proximal tubule cells is mediated by receptor‐mediated endocytosis and polarized transport systems that reflect final cell differentiation.
Loss‐of‐function mutations of the endosomal chloride–proton exchanger ClC‐5 (Dent's disease) cause a major trafficking defect in proximal tubule cells, associated with lysosomal dysfunction, oxidative stress and dedifferentiation/proliferation.
A similar but milder defect is associated with mutations in CFTR (cystic fibrosis transmembrane conductance regulator).
Vesicular chloride transport appears to be important for the integrity of the endolysosomal pathway in epithelial cells.
AbstractThe epithelial cells lining the proximal tubules of the kidney reabsorb a large amount of filtered ions and solutes owing to receptor‐mediated endocytosis and polarized transport systems that reflect final cell differentiation. Dedifferentiation of proximal tubule cells and dysfunction of receptor‐mediated endocytosis characterize Dent's disease, a rare disorder caused by inactivating mutations in the CLCN5 gene that encodes the endosomal chloride–proton exchanger, ClC‐5. The disease is characterized by a massive urinary loss of solutes (renal Fanconi syndrome), with severe metabolic complications and progressive renal failure. Investigations of mutations affecting the gating of ClC‐5 revealed that the proximal tubule dysfunction may occur despite normal endosomal acidification. In addition to defective endocytosis, proximal tubule cells lacking ClC‐5 show a trafficking defect in apical receptors and transporters, as well as lysosomal dysfunction and typical features of dedifferentiation, proliferation and oxidative stress. A similar but milder defect is observed in mouse models with defective CFTR, a chloride channel that is also expressed in the endosomes of proximal tubule cells. These data suggest a major role for endosomal chloride transport in the maintenance of epithelial differentiation and reabsorption capacity of the renal proximal tubule.
Getting to the heart of hERG K+ channel gating
Authors: Perry Matthew D. , Ng Chai‐Ann , Mann Stefan A. , Sadrieh Arash , Imtiaz Mohammad , Hill Adam P. , Vandenberg Jamie I. 
Published: March 2015

AbstractPotassium ion channels encoded by the human ether‐a‐go‐go related gene (hERG) form the ion‐conducting subunit of the rapid delayed rectifier potassium current (IKr). Although hERG channels exhibit a widespread tissue distribution they play a particularly important role in the heart. There has been considerable interest in hERG K+ channels for three main reasons. First, they have very unusual gating kinetics, most notably rapid and voltage‐dependent inactivation coupled to slow deactivation, which has led to the suggestion that they may play a specific role in the suppression of arrhythmias. Second, mutations in hERG are the cause of 30–40% of cases of congenital long QT syndrome (LQTS), the commonest inherited primary arrhythmia syndrome. Third, hERG is the molecular target for the vast majority of drugs that cause drug‐induced LQTS, the commonest cause of drug‐induced arrhythmias and cardiac death. Drug‐induced LQTS has now been reported for a large range of both cardiac and non‐cardiac drugs, in which this side effect is entirely undesired. In recent years there have been comprehensive reviews published on hERG K+ channels (Vandenberg et al. 2012) and we will not re‐cover this ground. Rather, we focus on more recent work on the structural basis and dynamics of hERG gating with an emphasis on how the latest developments may facilitate translational research in the area of stratifying risk of arrhythmias.
Organization of left–right coordination of neuronal activity in the mammalian spinal cord: Insights from computational modelling
Authors: Shevtsova Natalia A. , Talpalar Adolfo E. , Markin Sergey N. , Harris‐Warrick Ronald M. , Kiehn Ole , Rybak Ilya A. 
Published: March 2015

Key points
Coordination of neuronal activity between left and right sides of the mammalian spinal cord is provided by several sets of commissural interneurons (CINs) whose axons cross the midline. Genetically identified inhibitory V0D and excitatory V0V CINs and ipsilaterally projecting excitatory V2a interneurons were shown to secure left–right alternation at different locomotor speeds.
We have developed computational models of neuronal circuits in the spinal cord that include left and right rhythm‐generating centres interacting bilaterally via three parallel pathways mediated by V0D, V2a–V0V and V3 neuron populations.
The models reproduce the experimentally observed speed‐dependent left–right coordination in normal mice and the changes in coordination seen in mutants lacking specific neuron classes.
The models propose an explanation for several experimental results and provide insights into the organization of the spinal locomotor network and parallel CIN pathways involved in gait control at different locomotor speeds.
AbstractDifferent locomotor gaits in mammals, such as walking or galloping, are produced by coordinated activity in neuronal circuits in the spinal cord. Coordination of neuronal activity between left and right sides of the cord is provided by commissural interneurons (CINs), whose axons cross the midline. In this study, we construct and analyse two computational models of spinal locomotor circuits consisting of left and right rhythm generators interacting bilaterally via several neuronal pathways mediated by different CINs. The CIN populations incorporated in the models include the genetically identified inhibitory (V0D) and excitatory (V0V) subtypes of V0 CINs and excitatory V3 CINs. The model also includes the ipsilaterally projecting excitatory V2a interneurons mediating excitatory drive to the V0V CINs. The proposed network architectures and CIN connectivity allow the models to closely reproduce and suggest mechanistic explanations for several experimental observations. These phenomena include: different speed‐dependent contributions of V0D and V0V CINs and V2a interneurons to left–right alternation of neural activity, switching gaits between the left–right alternating walking‐like activity and the left–right synchronous hopping‐like pattern in mutants lacking specific neuron classes, and speed‐dependent asymmetric changes of flexor and extensor phase durations. The models provide insights into the architecture of spinal network and the organization of parallel inhibitory and excitatory CIN pathways and suggest explanations for how these pathways maintain alternating and synchronous gaits at different locomotor speeds. The models propose testable predictions about the neural organization and operation of mammalian locomotor circuits.
Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques
Authors: Hernandez V. , Abella R. , Calvo J. F. , Jurado‐Bruggemann D. , Sancho I. , Carrasco P. 
Published: March 2015

Purpose:Several authors have recommended a 2 mm tolerance for multileaf collimator (MLC) positioning in sliding window treatments. In volumetric modulated arc therapy (VMAT) treatments, however, the optimal tolerance for MLC positioning remains unknown. In this paper, the authors present the results of a multicenter study to determine the optimal tolerance for both techniques.Methods:The procedure used is based on dynalog file analysis. The study was carried out using seven Varian linear accelerators from five different centers. Dynalogs were collected from over 100 000 clinical treatments and in‐house software was used to compute the number of tolerance faults as a function of the user‐defined tolerance. Thus, the optimal value for this tolerance, defined as the lowest achievable value, was investigated.Results:Dynalog files accurately predict the number of tolerance faults as a function of the tolerance value, especially for low fault incidences. All MLCs behaved similarly and the Millennium120 and the HD120 models yielded comparable results. In sliding window techniques, the number of beams with an incidence of hold‐offs >1% rapidly decreases for a tolerance of 1.5 mm. In VMAT techniques, the number of tolerance faults sharply drops for tolerances around 2 mm. For a tolerance of 2.5 mm, less than 0.1% of the VMAT arcs presented tolerance faults.Conclusions:Dynalog analysis provides a feasible method for investigating the optimal tolerance for MLC positioning in dynamic fields. In sliding window treatments, the tolerance of 2 mm was found to be adequate, although it can be reduced to 1.5 mm. In VMAT treatments, the typically used 5 mm tolerance is excessively high. Instead, a tolerance of 2.5 mm is recommended.
Lung dynamic MRI deblurring using low‐rank decomposition and dictionary learning
Authors: Gou Shuiping , Wang Yueyue , Wu Jiaolong , Lee Percy , Sheng Ke 
Published: March 2015

Purpose:Lung dynamic MRI (dMRI) has emerged to be an appealing tool to quantify lung motion for both planning and treatment guidance purposes. However, this modality can result in blurry images due to intrinsically low signal‐to‐noise ratio in the lung and spatial/temporal interpolation. The image blurring could adversely affect the image processing that depends on the availability of fine landmarks. The purpose of this study is to reduce dMRI blurring using image postprocessing.Methods:To enhance the image quality and exploit the spatiotemporal continuity of dMRI sequences, a low‐rank decomposition and dictionary learning (LDDL) method was employed to deblur lung dMRI and enhance the conspicuity of lung blood vessels. Fifty frames of continuous 2D coronal dMRI frames using a steady state free precession sequence were obtained from five subjects including two healthy volunteer and three lung cancer patients. In LDDL, the lung dMRI was decomposed into sparse and low‐rank components. Dictionary learning was employed to estimate the blurring kernel based on the whole image, low‐rank or sparse component of the first image in the lung MRI sequence. Deblurring was performed on the whole image sequences using deconvolution based on the estimated blur kernel. The deblurring results were quantified using an automated blood vessel extraction method based on the classification of Hessian matrix filtered images. Accuracy of automated extraction was calculated using manual segmentation of the blood vessels as the ground truth.Results:In the pilot study, LDDL based on the blurring kernel estimated from the sparse component led to performance superior to the other ways of kernel estimation. LDDL consistently improved image contrast and fine feature conspicuity of the original MRI without introducing artifacts. The accuracy of automated blood vessel extraction was on average increased by 16% using manual segmentation as the ground truth.Conclusions:Image blurring in dMRI images can be effectively reduced using a low‐rank decomposition and dictionary learning method using kernels estimated by the sparse component.
Monte Carlo simulation of PET and SPECT imaging of 90Y
Authors: Takahashi Akihiko , Himuro Kazuhiko , Yamashita Yasuo , Komiya Isao , Baba Shingo , Sasaki Masayuki 
Published: March 2015

Purpose:Yittrium‐90 (90Y) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single‐photon emission computed tomography (SPECT). However, because 90Y also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of 90Y bremsstrahlung SPECT, PET imaging has been suggested as an alternative. In this paper, the authors present the Monte Carlo‐based simulation–reconstruction framework for 90Y to comprehensively analyze the PET and SPECT imaging techniques and to quantitatively consider the disadvantages associated with them.Methods:Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP‐PET) generates a sinogram, and reconstructs the tomography image using a time‐of‐flight ordered subset expectation maximization (TOF‐OSEM) algorithm with attenuation compensation. To evaluate MCEP‐PET, simulated results of 18F PET imaging were compared with the experimental results. The results confirmed that MCEP‐PET can simulate the experimental results very well. The SPECT code (MCEP‐SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded 90Y bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of 90Y without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min.Results:The simulated 90Y‐PET image accurately simulated the experimental results. PET image is visually superior to SPECT image because of the low background noise. The simulation reveals that the detected photon number in SPECT is comparable to that of PET, but the large fraction (approximately 75%) of scattered and penetration photons contaminates SPECT image. The lower limit of 90Y detection in SPECT image was approximately 200 kBq/ml, while that in PET image was approximately 100 kBq/ml.Conclusions:By comparing the background noise level and the image concentration profile of both the techniques, PET image quality was determined to be superior to that of bremsstrahlung SPECT. The developed simulation codes will be very useful in the future investigations of PET and bremsstrahlung SPECT imaging of 90Y.
Volume loss from Antarctic ice shelves is accelerating
Authors: Paolo Fernando S. , Fricker Helen A. , Padman Laurie 
Published: March 2015

Disappearing faster around the edgesThe floating ice shelves around Antarctica, which buttress ice streams from the continent and slow their discharge into the sea, are thinning at faster rates. Paoloet al.present satellite data showing that ice shelves in many regions around the edge of the continent are losing mass. This result increases concern about how fast sea level might rise as climate continues to warm. If warming continues to cause ice shelves to thin, as they have for the past couple of decades, their disappearance may allow land-based ice to collapse and melt.Science, this issue p.327
Draft Genome Sequences of Four Bacillus thermoamylovorans Strains Isolated from Milk and Acacia Gum, a Food Ingredient
Authors: Krawczyk Antonina O. , Berendsen Erwin M. , Eijlander Robyn T. , de Jong Anne , Wells-Bennik Marjon H. J. , Kuipers Oscar P. 
Published: March 2015

ABSTRACT

The thermophilic bacterium
Bacillus thermoamylovorans
produces highly heat-resistant spores that can contaminate food products, leading to their spoilage. Here, we present the whole-genome sequences of four B. thermoamylovorans strains, isolated from milk and acacia gum.
Draft Genome Sequence of the Yeast
Starmerella bombicola
NBRC10243, a Producer of Sophorolipids, Glycolipid Biosurfactants
Authors: Matsuzawa Tomohiko , Koike Hideaki , Saika Azusa , Fukuoka Tokuma , Sato Shun , Habe Hiroshi , Kitamoto Dai , Morita Tomotake 
Published: March 2015

ABSTRACT

The yeast
Starmerella bombicola
NBRC10243 is an excellent producer of sophorolipids (SLs) from various feedstocks. Here, we report the draft genome sequence of S. bombicola NBRC10243. Analysis of the sequence may provide insight into the properties of this yeast that make it superior for use in the production of functional glycolipids and biomolecules, leading to the further development of S. bombicola NBRC10243 for industrial applications.
Whole-Genome Sequencing of Mycoplasma mycoides subsp. mycoides Italian Strain 57/13, the Causative Agent of Contagious Bovine Pleuropneumonia
Authors: Orsini M. , Krasteva I. , Marcacci M. , Ancora M. , Ciammaruconi A. , Gentile B. , Lista F. , Pini A. , Scacchia M. , Sacchini F. , Cammà C. 
Published: March 2015

ABSTRACT

Mycoplasma mycoides
subsp. mycoides is generally considered one of most pathogenic Mycoplasma species, and it is the etiological agent of contagious bovine pleuropneumonia (CBPP). Here, we present the annotated genome sequence of M. mycoides subsp. mycoides Italian strain 57/13, isolated in 1992 during CBPP outbreaks in Italy.