bluuebunny/crossref_metadata_2025_split huggingface dataset:
The amoeboidal Dictyostelium aquaporin AqpB is gated via Tyr216 and aqpB gene deletion affects random cell motility
Authors: von Bülow Julia , Golldack André , Albers Tineke , Beitz Eric 
Published: December 2014

Background informationRegulation of aquaporin (AQPs) water channels mostly occurs on the transcriptional level or by intracellular trafficking. Direct AQP gating is comparatively rare and is described mainly for fungi and plants. Earlier, we identified a gated water‐specific AQP in Dictyostelium discoideum, AqpB, which is opened by truncation of an extended intracellular loop D (AqpB Δ208–219).ResultsWe show that Tyr216 of loop D is a key residue in the gating mechanism possibly involving phosphorylation. Mutation of Tyr216 to aspartate or glutamate initiated water permeability (Pf = 69 μm/s) to the same extent as AqpB Δ208–219, whereas neither replacement of Tyr216 by a positive arginine (Y216R) nor introduction of a negative charge in a neighbouring position (T217D) opened the channel. We overexpressed AqpB wildtype and AqpB Δ208–219 as GFP fusion constructs in Dictyostelium amoebae and found that the truncated, permanently open AqpB yielded cells with reduced capability to cope with hypotonic stress. Genetic deletion of aqpB yielded a strain with significantly reduced speed of random motility (4.5 μm/min vs. 6.3 μm/min of wildtype cells). Yet, chemotaxis towards folate and cAMP was unaffected. In this context, we identified a second, so‐far uncharacterised amoeboidal AQP, AqpD, whose role in directed cell locomotion needs to be established.ConclusionOur data add to the completion of the Dictyostelium model for cell motility and show that knowledge on the expression, permeability properties and localisation of amoeboidal AQPs are crucial for further development of the system.
Simulated training in colonoscopic stenting of colonic strictures: validation of a cadaver model
Authors: Iordache F. , Bucobo J. C. , Devlin D. , You K. , Bergamaschi R. 
Published: December 2014

AbstractAimThere are currently no available simulation models for training in colonoscopic stent deployment. The aim of this study was to validate a cadaver model for simulation training in colonoscopy with stent deployment for colonic strictures.MethodThis was a prospective study enrolling surgeons at a single institution. Participants performed colonoscopic stenting on a cadaver model. Their performance was assessed by two independent observers. Measurements were performed for quantitative analysis (time to identify stenosis, time for deployment, accuracy) and a weighted score was devised for assessment. The Mann–Whitney U‐test and Student's t‐test were used for nonparametric and parametric data, respectively. Cohen's kappa coefficient was used for reliability.ResultsTwenty participants performed a colonoscopy with deployment of a self‐expandable metallic stent in two cadavers (groups A and B) with 20 strictures overall. The median time was 206 s. The model was able to differentiate between experts and novices (P = 0. 013). The results showed a good consensus estimate of reliability, with kappa = 0.571 (P < 0.0001).ConclusionThe cadaver model described in this study has content, construct and concurrent validity for simulation training in colonoscopic deployment of self‐expandable stents for colonic strictures. Further studies are needed to evaluate the predictive validity of this model in terms of skill transfer to clinical practice.
The Interaction of Language‐Specific and Universal Factors During the Acquisition of Morphophonemic Alternations With Exceptions
Authors: Baer‐Henney Dinah , Kügler Frank , van de Vijver Ruben 
Published: December 2014

AbstractUsing the artificial language paradigm, we studied the acquisition of morphophonemic alternations with exceptions by 160 German adult learners. We tested the acquisition of two types of alternations in two regularity conditions while additionally varying length of training. In the first alternation, a vowel harmony, backness of the stem vowel determines backness of the suffix. This process is grounded in substance (phonetic motivation), and this universal phonetic factor bolsters learning a generalization. In the second alternation, tenseness of the stem vowel determines backness of the suffix vowel. This process is not based in substance, but it reflects a phonotactic property of German and our participants benefit from this language‐specific factor. We found that learners use both cues, while substantive bias surfaces mainly in the most unstable situation. We show that language‐specific and universal factors interact in learning.
Teratosphaeria gauchensis associated with trunk, stem and foliar lesions of Eucalyptus globulus in Portugal
Authors: Silva M. R. C. , Diogo E. , Bragança H. , Machado H. , Phillips A. J. L. 
Published: December 2014

SummaryTeratosphaeria gauchensis and T. zuluensis both cause a stem canker of eucalypts that leads to serious damage in various parts of the world. Until recently, this disease was unknown in Portugal. Nevertheless, severe damage to Eucalyptus globulus has been observed in Portugal since 2006 when symptoms appeared as necrotic spots on young green stems and leaves, twig lesions, and dark oval‐shaped lesions on stems and trunks. The isolates from affected E. globulus tree plantations were identified using sequence data of the ITS1‐5.8S‐ITS2 and EF‐1α clusters, together with morphological characteristics. Based on these results, the causal organism was identified as T. gauchensis, which represents the first report of this pathogen from Portugal.
Chronic alcohol intake abolishes the relationship between dopamine synthesis capacity and learning signals in the ventral striatum
Authors: Deserno Lorenz , Beck Anne , Huys Quentin J. M. , Lorenz Robert C. , Buchert Ralph , Buchholz Hans‐Georg , Plotkin Michail , Kumakara Yoshitaka , Cumming Paul , Heinze Hans‐Jochen , Grace Anthony A. , Rapp Michael A. , Schlagenhauf Florian , Heinz Andreas 
Published: December 2014

AbstractDrugs of abuse elicit dopamine release in the ventral striatum, possibly biasing dopamine‐driven reinforcement learning towards drug‐related reward at the expense of non‐drug‐related reward. Indeed, in alcohol‐dependent patients, reactivity in dopaminergic target areas is shifted from non‐drug‐related stimuli towards drug‐related stimuli. Such ‘hijacked’ dopamine signals may impair flexible learning from non‐drug‐related rewards, and thus promote craving for the drug of abuse. Here, we used functional magnetic resonance imaging to measure ventral striatal activation by reward prediction errors (RPEs) during a probabilistic reversal learning task in recently detoxified alcohol‐dependent patients and healthy controls (N = 27). All participants also underwent 6‐[18F]fluoro‐DOPApositron emission tomography to assess ventral striatal dopamine synthesis capacity. Neither ventral striatal activation byRPEs nor striatal dopamine synthesis capacity differed between groups. However, ventral striatal coding ofRPEs correlated inversely with craving in patients. Furthermore, we found a negative correlation between ventral striatal coding ofRPEs and dopamine synthesis capacity in healthy controls, but not in alcohol‐dependent patients. Moderator analyses showed that the magnitude of the association between dopamine synthesis capacity andRPEcoding depended on the amount of chronic, habitual alcohol intake. Despite the relatively small sample size, a power analysis supports the reported results. Using a multimodal imaging approach, this study suggests that dopaminergic modulation of neural learning signals is disrupted in alcohol dependence in proportion to long‐term alcohol intake of patients. Alcohol intake may perpetuate itself by interfering with dopaminergic modulation of neural learning signals in the ventral striatum, thus increasing craving for habitual drug intake.
Stimulus intensity determines experience‐dependent modifications in neocortical neuron firing rates
Authors: Glazewski Stanislaw , Barth Alison L. 
Published: December 2014

AbstractAlthough subthreshold inputs of neocortical sensory neurons are broadly tuned, the spiking output is more restricted. These subthreshold inputs provide a substrate for stimulus intensity‐dependent changes their spiking output, as well as for experience‐dependent plasticity to alter firing properties. Here we investigated how different stimulus intensities modified the firing output of individual neurons in layer 2/3 of the mouse barrel cortex. Decreasing stimulus intensity over a 30‐fold range lowered the firing rates evoked by principal whisker stimulation and reduced the overall size of the responding ensemble in whisker‐undeprived animals. We then examined how these responses were changed after single‐whisker experience (SWE). After 7 days of SWE, the mean magnitude of response to spared whisker stimulation at the highest stimulus intensity was not altered. However, lower‐intensity whisker stimulation revealed a more than 10‐fold increase in mean firing output compared with control animals. Also, under control conditions, only ~15% of neurons showed any firing at low stimulus intensity, compared with more than 70% of neurons after SWE. However, response changes measured in the immediately surrounding representations were detected only for the highest stimulus intensity. Overall, these data showed that the measurement of experience‐dependent changes in the spike output of neocortical neurons was highly dependent upon stimulus intensity.
Interests shape how adolescents pay attention: the interaction of motivation and top‐down attentional processes in biasing sensory activations to anticipated events
Authors: Banerjee Snigdha , Frey Hans‐Peter , Molholm Sophie , Foxe John J. 
Published: December 2014

AbstractThe voluntary allocation of attention to environmental inputs is a crucial mechanism of healthy cognitive functioning, and is probably influenced by an observer's level of interest in a stimulus. For example, an individual who is passionate about soccer but bored by botany will obviously be more attentive at a soccer match than an orchid show. The influence of monetary rewards on attention has been examined, but the impact of more common motivating factors (i.e. the level of interest in the materials under observation) remains unclear, especially during development. Here, stimulus sets were designed based on survey measures of the level of interest of adolescent participants in several item classes. High‐density electroencephalography was recorded during a cued spatial attention task in which stimuli of high or low interest were presented in separate blocks. The motivational impact on performance of a spatial attention task was assessed, along with event‐related potential measures of anticipatory top‐down attention. As predicted, performance was improved for the spatial target detection of high interest items. Further, the impact of motivation was observed in parieto‐occipital processes associated with anticipatory top‐down spatial attention. The anticipatory activity over these regions was also increased for high vs. low interest stimuli, irrespective of the direction of spatial attention. The results also showed stronger anticipatory attentional and motivational modulations over the right vs. left parieto‐occipital cortex. These data suggest that motivation enhances top‐down attentional processes, and can independently shape activations in sensory regions in anticipation of events. They also suggest that attentional functions across hemispheres may not fully mature until late adolescence.
Quantifying ecological memory in plant and ecosystem processes
Authors: Ogle Kiona , Barber Jarrett J. , Barron‐Gafford Greg A. , Bentley Lisa Patrick , Young Jessica M. , Huxman Travis E. , Loik Michael E. , Tissue David T. 
Published: December 2014

AbstractThe role of time in ecology has a long history of investigation, but ecologists have largely restricted their attention to the influence of concurrent abiotic conditions on rates and magnitudes of important ecological processes. Recently, however, ecologists have improved their understanding of ecological processes by explicitly considering the effects of antecedent conditions. To broadly help in studying the role of time, we evaluate the length, temporal pattern, and strength of memory with respect to the influence of antecedent conditions on current ecological dynamics. We developed the stochastic antecedent modelling (SAM) framework as a flexible analytic approach for evaluating exogenous and endogenous process components of memory in a system of interest. We designed SAM to be useful in revealing novel insights promoting further study, illustrated in four examples with different degrees of complexity and varying time scales: stomatal conductance, soil respiration, ecosystem productivity, and tree growth. Models with antecedent effects explained an additional 18–28% of response variation compared to models without antecedent effects. Moreover, SAM also enabled identification of potential mechanisms that underlie components of memory, thus revealing temporal properties that are not apparent from traditional treatments of ecological time‐series data and facilitating new hypothesis generation and additional research.
Vertigo and nystagmus in orthostatic hypotension
Authors: Choi J.‐H. , Seo J.‐D. , Kim M.‐J. , Choi B.‐Y. , Choi Y. R. , Cho B. M. , Kim J. S. , Choi K.‐D. 
Published: December 2014

Background and purposeGeneralized cerebral ischaemia from cardiovascular dysfunction usually leads to presyncopal dizziness, but several studies reported a higher frequency of rotatory vertigo in cardiovascular patients. Whether generalized cerebral ischaemia due to cardiovascular disorders may produce objective vestibular dysfunction was investigated.MethodsThirty‐three patients with orthostatic dizziness/vertigo due to profound orthostatic hypotension and 30 controls were recruited. All participants underwent recording of eye movements during two orthostatic challenging tests: the Schellong and the squatting−standing tests. Most patients had neuroimaging, and patients with abnormal eye movements were subjected to follow‐up evaluations.ResultsSymptoms associated with orthostatic dizziness/vertigo included blurred vision, fainting and tinnitus. Ten (30%) of 33 patients developed rotatory vertigo and nystagmus during the Schellong (n = 5) or squatting−standing test (n = 5). Four of them showed pure downbeat nystagmus whilst five had downbeat and horizontal nystagmus with or without torsional component. Patients with orthostatic nystagmus had shorter duration of orthostatic intolerance than those without nystagmus (1.0 ± 1.6 vs. 11.0 ± 9.7 months, P < 0.001). In two patients, orthostatic nystagmus disappeared during follow‐up despite the persistence of profound orthostatic hypotension.ConclusionsGeneralized cerebral ischaemia caused by orthostatic hypotension induces rotatory vertigo due to objective vestibular dysfunction. The presence of orthostatic vertigo and nystagmus has an association with the duration of orthostatic intolerance.
White matter abnormalities associate with type and localization of focal epileptogenic lesions
Authors: Campos Brunno M. , Coan Ana C. , Beltramini Guilherme C. , Liu Min , Yassuda Clarissa L. , Ghizoni Enrico , Beaulieu Christian , Gross Donald W. , Cendes Fernando 
Published: December 2014

SummaryObjectiveTo evaluate white matter (WM) integrity of distinct groups of patients with antiepileptic drug (AED)–resistant localization‐related epilepsies.MethodsWe used diffusion tensor imaging (DTI) fiber‐tractography and voxel‐based morphometry (VBM) to investigate differences of WM micro‐ and macrostructural integrity in patients with different drug‐resistant localization‐related epilepsies: 17 with temporal lobe epilepsy with magnetic resonance imaging (MRI) signs of hippocampal sclerosis (TLE‐HS), 17 with TLE and normal MRI (TLE‐NL), 14 with frontal lobe epilepsy and subtle MRI signs of focal cortical dysplasia (FLE‐FCD), and 112 healthy controls. We performed fiber‐tractography using a semiautomatic deterministic method to yield average fractional anisotropy (FA), axial (AD), and radial (RD) diffusivity ipsilateral and contralateral to the epileptogenic zone of the following tracts based on their functional and anatomic relevance: body of fornix (BoF), body of cingulum (BoC), inferior frontal occipital (IFO), and uncinate fasciculi (UF). In addition, we performed VBM of the WM maps to assess macrostructural integrity differences among groups.ResultsTLE‐HS had ipsilateral and contralateral decreased FA and increased RD for all tracts. VBM showed WM alterations mainly in the ipsilateral parahippocampal region and contralateral superior temporal gyrus. FLE‐FCD showed bilateral FA decreases only in the BoC and ipsilateral RD increases also in the BoC. VBM showed WM reduction mainly in the ipsilateral precuneus and posterior and anterior cingulum. No significant WM alterations were found in the TLE‐NL in DTI or VBM analysis.SignificanceWM abnormalities differ in distinct AED‐resistant localization‐related epilepsies. The diverse distribution of the WM damage in these patients suggests that the localization of the epileptic networks may play a role in the WM burden. However, the distinct degree of this damage, more accentuated in TLE‐HS, also suggests that the underlying cause of the epilepsy is probably an additional factor to explain this WM damage.
Comparative analyses of tooth wear in free‐ranging and captive wild equids
Authors: Taylor L. A. , Müller D. W. H. , Schwitzer C. , Kaiser T. M. , Castell J. C. , Clauss M. , Schulz‐Kornas E. 
Published: December 2014

SummaryReasons for performing studyCaptive breeding has played a crucial role in the conservation of threatened equid species. Grazing ruminants and rhinoceros in captivity have less abrasion‐dominated tooth wear than their free‐ranging conspecifics, with potential negative consequences for their health. However, a similar study on wild equids in captivity is missing.ObjectivesThe aim was to establish if different tooth wear patterns are exhibited by free‐ranging and captive equids.Study designCross‐sectional study of museum specimens comparing free‐ranging and captive equids.MethodsDental casts of maxillary cheek teeth of 228 museum specimens (122 from free‐ranging and 106 from captive individuals) of 7 wild equid species were analysed using the extended mesowear method. Although teeth showing specific abnormalities were not scored, the presence of focal overgrowths (hooks) of the rostral premolars (106, 206) was recorded.ResultsCaptive Equus ferus przewalskii, E. grevyi, E. hemionus, E. quagga boehmi and E. zebra hartmannae have less abrasion‐dominated tooth wear on their premolars than their free‐ranging conspecifics (P<0.001). Fewer differences were exhibited between populations in the molars. No differences were exhibited in the distal cusp of the molars (110, 210) between populations, except in a small sample of E. kiang. Captive equids exhibited more homogeneous wear along the tooth row whereas free‐ranging equids exhibited a tooth wear gradient, with more abrasion on premolars than molars. There were more rostral hooks on the premolars (106, 206) in the captive than the free‐ranging population (P = 0.02).ConclusionsCaptive equids did experience less abrasion‐dominated tooth wear than their free‐ranging conspecifics, but the differences in tooth wear were less pronounced than those between captive and free‐ranging wild ruminant and rhinoceros species. This indicates that feeding regimes for captive equids deviate less from natural diets than those for captive ruminants and rhinoceros but that factors leading to hook formation, in particular feeding height, should receive special attention.The Summary is available in Chinese – see Supporting information.
A meta‐analysis of haddock size‐selection data
Authors: Fryer Robert John , O'Neill Finbarr Gerard , Edridge Alexius 
Published: December 2014

AbstractMany jurisdictions have introduced management regimes prohibiting or limiting discarding, and a key objective of the European Union Common Fisheries Policy is the gradual elimination of discards. One way of reducing the catch of unwanted fish is to use more size‐selective gears. Gear‐based management options can best be explored using models that predict size selection across a wide range of variables related to gear design. Such a model is developed for haddock (Melanogrammus aeglefinus) through a meta‐analysis of 21 trials of codend selection and 19 trials of the combined selection of the codend and a square mesh panel. Individual‐haul estimates of the 50% retention length (l50) and the selection range (SR) are related to a set of explanatory variables through a structural model that describes the dual process of panel and codend selection. Codend l50 and SR are positively related to codend mesh size and negatively related to the codend twine diameter. Codend l50 is also negatively related to the number of open meshes around the codend circumference. Panel l50 increases with panel mesh size. The panel contributes more to gear selection as it is moved closer to the codline. The panel is most effective between November and January and least between May and July, periods which broadly coincide with peak and poor haddock condition. The results are illustrated for a typical trawler targeting haddock in the Scottish whitefish sector, and the utility of the model for gear design and legislation is discussed.
Significant nonsymbiotic nitrogen fixation in Patagonian ombrotrophic bogs
Authors: Knorr Klaus‐Holger , Horn Marcus A. , Borken Werner 
Published: December 2014

AbstractNitrogen (N) nutrition in pristine peatlands relies on the natural input of inorganic N through atmospheric deposition or biological dinitrogen (N2) fixation. However, N2 fixation and its significance for N cycling, plant productivity, and peat buildup are mostly associated with the presence of Sphagnum mosses. Here, we report high nonsymbiotic N2‐fixation rates in two pristine Patagonian bogs with diversified vegetation and natural N deposition. Nonsymbiotic N2 fixation was measured in samples from 0 to 10, 10 to 20, and 40 to 50 cm depth using the 15N2 assay as well as the acetylene reduction assay (ARA). The ARA considerably underestimated N2 fixation and can thus not be recommended for peatland studies. Based on the 15N2 assay, high nonsymbiotic N2‐fixation rates of 0.3–1.4 μmol N2 g−1 day−1 were found down to 50 cm under micro‐oxic conditions (2 vol.%) in samples from plots covered by Sphagnum magellanicum or by vascular cushion plants, latter characterized by dense and deep aerenchyma roots. Peat N concentrations point to greater potential of nonsymbiotic N2 fixation under cushion plants, likely because of the availability of easily decomposable organic compounds and oxic conditions in the rhizosphere. In the Sphagnum plots, high N2 fixation below 10 cm depth rather reflects the potential during dry periods or low water level when oxygen penetrates the top peat layer and triggers peat mineralization. Natural abundance of the 15N isotope of live Sphagnum (5.6 δ‰) from 0 to 10 cm points to solely N uptake from atmospheric deposition and nonsymbiotic N2 fixation. A mean 15N signature of −0.7 δ‰ of peat from the cushion plant plots indicates additional N supply from N mineralization. Our findings suggest that nonsymbiotic N2 fixation overcomes N deficiency in different vegetation communities and has great significance for N cycling and peat accumulation in pristine peatlands.