bluuebunny/crossref_metadata_2025 huggingface dataset:
United European Gastroenterology Week scientific abstracts and their progression to full publication
Authors: Raju Suneil A. , Sanders David S. , Akram Rahim , Glover Rebecca , Al-Rifaie Ammar , Peever Elise , Purves Josh , Scanu Emily , Kurien Matthew
Published: July 2017

Objective

Abstracts presentations at scientific meetings enable rapid dissemination of novel research. The percentage of abstracts that proceed to full publication from differing medical specialties is highly variable. This study aims to evaluate the outcomes of abstracts presented at the United European Gastroenterology Week (UEGW).

Materials and methods

All abstracts presented at UEGW between 2009 and 2011 were assessed. Cross-referencing of the first author, senior author and at least one keyword of the abstract was performed using PubMed and EMBASE databases. Abstracts and possible resultant full publications were then examined in tandem to ensure that they represented the same study. Data were also collected on lag time to publication, journal impact factors, country of the author and factors influencing subsequent publication.

Results

A total of 6785 abstracts (1438 oral and 5347 poster presentations) were presented during the period assessed. Of these, 2099 (30.9%) proceeded to full publication in indexed journals. Oral abstract presentations were most likely to proceed to full publication compared with poster presentations (odds ratio: 1.38, 95% confidence interval: 1.22–1.56) and were more likely to achieve publication in higher impact journals (median impact factor 4.78 vs. 2.89, P<0.0005). The median lag time to full publication was 15 (IQR: 7–15) months. The Netherlands had the highest United European Gastroenterology abstract conversion rate to full publication (46.8%).

Conclusion

This is the first study to assess the publication rates of UEGW. Findings are favourable with similar studies from other societies.
The Presence of Childhood Attention Deficit/Hyperactivity Disorder May Be Associated With Interpersonal Sensitivity in Patients With Social Anxiety Disorder
Authors: KOYUNCU AHMET , ÇELEBI FAHRI , ERTEKIN ERHAN , MEMIŞ ÇAĞDAŞ Ö. , TÜKEL RAŞIT
Published: July 2017

The goal of this study was to evaluate a possible association between childhood attention deficit/hyperactivity disorder (ADHD) and interpersonal sensitivity in patients with social anxiety disorder (SAD). The study involved 125 adult outpatients with a primary diagnosis of SAD. To evaluate childhood ADHD, the ADHD module of the Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version (K-SADS-PL) was used. Clinical and sociodemographic data were collected and clinical rating scales were completed. Mean total scores on the Interpersonal Sensitivity Measure were significantly higher in the group with SAD and ADHD than in the group with SAD without ADHD. Interpersonal Sensitivity Measure total scores were positively correlated with the severity of SAD symptoms and negatively correlated with mean age of onset of SAD. The presence of childhood ADHD may be associated with greater interpersonal sensitivity in patients with SAD.
Upper Lip Reconstruction
Authors: Luce Edward A.
Published: July 2017

Reconstruction of an aesthetically acceptable and functional upper lip requires a careful consideration of the transverse and vertical soft tissue, muscle, and skin deficiency. This review focuses on the reconstructive aspects of the upper lip. The functional anatomy of the upper lip is considerably complex and includes paired muscles in addition to the orbicularis, elevators of both the upper lip and commissure. The muscular action of facial expression recruits different sets of these paired muscles. Unlike the aesthetic uniform appearance of the lower lip commissure to commissure, the upper lip aesthetics can be divided into a central, philtrum unit, and a lateral upper lip unit. The lateral unit can be further subdivided into medial and lateral elements, with the medial more fixed and less mobile because of attachments superiorly at the alar sill and base. Reconstruction of the philtrum is best accomplished with an Abbe flap. Methods to reconstruct the lateral unit hinge on location, medial versus lateral, and defect size. A conceptual approach to successful reconstruction of upper lip defects entails the use of a classification based on the aesthetic unit, appropriate selection of the reconstructive option for a particular defect driven by location and size, and careful consideration given to a final result in harmony both transversely and vertically with the lower lip and the remainder of the midface.
Patient Education and Discharge Planning to Prevent Functional Decline in the Older Adult
Authors: Gunn Sharon
Published: July 2017

The population in the United States is aging, and persons older than 65 years account for over 50% of healthcare costs. Preventing functional decline in older adults through patient education and optimal discharge planning is one way we can succeed in decreasing healthcare costs, readmissions, and mortality in this population. The aim of this article is to present viable healthcare policy options to prevent or minimize functional decline in the older adult, regardless of what health-related facility the person enters. Policy objectives include mandating functional screening tests on all persons 65 years and older, addressing functional status as a required element of discharge planning, tracking and reporting patient outcomes, and utilizing advanced practice nurses to the full extent of their education and scope of practice. Three policy options are presented, analyzed, and compared. The summary concludes with a recommended policy option.
Rural Older Adult Physical Activity Promotion
Authors: Witcher Chad S. G.
Published: July 2017

The last 3 decades of research in exercise science have demonstrated the role of physical activity (PA) in maintaining, as well as improving, a variety of health outcome measures in older adults. However, rates of regular participation in PA remain relatively low. This is a significant public health issue, as inactive and insufficiently physically active older adults are more likely to develop chronic diseases such as heart disease, stroke, and diabetes. Furthermore, disparities in PA exist. For example, older adults in rural areas are less physically active than those in urban areas. Determining why such disparities in health and PA participation exist is a complex, but important endeavor and, presently, the underlying mechanisms are not well understood. By adopting interpretive research methodologies and methods (ie, “qualitative”), we can explore various contextual factors such as historical influences, social norms, and the cultural milieu of particular locations, which may influence area-specific participation in PA. Drawing upon research conducted in Canada, this article discusses the PA perceptions, preferences, and experiences of rural older adults, contextualizes these findings for practice, and considers to what extent a “rethink” of approaches to PA promotion may be necessary to serve future generations of rural older adults.
Rapid Number Naming and Quantitative Eye Movements May Reflect Contact Sport Exposure in a Collegiate Ice Hockey Cohort
Authors: Hasanaj Lisena , Thawani Sujata P. , Webb Nikki , Drattell Julia D. , Serrano Liliana , Nolan Rachel C. , Raynowska Jenelle , Hudson Todd E. , Rizzo John-Ross , Dai Weiwei , McComb Bryan , Goldberg Judith D. , Rucker Janet C. , Galetta Steven L. , Balcer Laura J.
Published: July 2017

Background:

The King-Devick (K-D) test of rapid number naming is a reliable visual performance measure that is a sensitive sideline indicator of concussion when time scores worsen (lengthen) from preseason baseline. Within cohorts of youth athletes <18 years old, baseline K-D times become faster with increasing age. We determined the relation of rapid number-naming time scores on the K-D test to electronic measurements of saccade performance during preseason baseline assessments in a collegiate ice hockey team cohort. Within this group of young adult athletes, we also sought to examine the potential role for player age in determining baseline scores.

Methods:

Athletes from a collegiate ice hockey team received preseason baseline testing as part of an ongoing study of rapid rink-side performance measures for concussion. These included the K-D test (spiral-bound cards and tablet computer versions). Participants also performed a laboratory-based version of the K-D test with simultaneous infrared-based video-oculographic recordings using an EyeLink 1000+. This allowed measurement of the temporal and spatial characteristics of eye movements, including saccadic velocity, duration, and intersaccadic interval (ISI).

Results:

Among 13 male athletes, aged 18–23 years (mean 20.5 ± 1.6 years), prolongation of the ISI (a combined measure of saccade latency and fixation duration) was the measure most associated with slower baseline time scores for the EyeLink-paired K-D (mean 38.2 ± 6.2 seconds, r = 0.88 [95% CI 0.63–0.96], P = 0.0001), the K-D spiral-bound cards (36.6 ± 5.9 seconds, r = 0.60 [95% CI 0.08–0.87], P = 0.03), and K-D computerized tablet version (39.1 ± 5.4 seconds, r = 0.79 [95% CI 0.42–0.93], P = 0.001). In this cohort, older age was a predictor of longer (worse) K-D baseline time performance (age vs EyeLink-paired K-D: r = 0.70 [95% CI 0.24–0.90], P = 0.008; age vs K-D spiral-bound cards: r = 0.57 [95% CI 0.03–0.85], P = 0.04; age vs K-D tablet version: r = 0.59 [95% CI 0.06–0.86], P = 0.03) as well as prolonged ISI (r = 0.62 [95% CI 0.11–0.87], P = 0.02). Slower baseline K-D times were not associated with greater numbers of reported prior concussions.

Conclusions:

Rapid number-naming performance using the K-D at preseason baseline in this small cohort of collegiate ice hockey players is best correlated with ISI among eye movement-recording measures. Baseline K-D scores notably worsened with increasing age, but not with numbers of prior concussions in this small cohort. While these findings require further investigation by larger studies of contact and noncontact sports athletes, they suggest that duration of contact sports exposure may influence preseason test performance.
Asymmetric drop coalescence launches fungal ballistospores with directionality
Authors: Liu Fangjie , Chavez Roger L. , Patek S. N. , Pringle Anne , Feng James J. , Chen Chuan-Hua
Published: July 2017

Thousands of fungal species use surface energy to power the launch of their ballistospores. The surface energy is released when a spherical Buller's drop at the spore's hilar appendix merges with a flattened drop on the adaxial side of the spore. The launching mechanism is primarily understood in terms of energetic models, and crucial features such as launching directionality are unexplained. Integrating experiments and simulations, we advance a mechanistic model based on the capillary–inertial coalescence between the Buller's drop and the adaxial drop, a pair that is asymmetric in size, shape and relative position. The asymmetric coalescence is surprisingly effective and robust, producing a launching momentum governed by the Buller's drop and a launching direction along the adaxial plane of the spore. These key functions of momentum generation and directional control are elucidated by numerical simulations, demonstrated on spore-mimicking particles, and corroborated by published ballistospore kinematics. Our work places the morphological and kinematic diversity of ballistospores into a general mechanical framework, and points to a generic catapulting mechanism of colloidal particles with implications for both biology and engineering.
The role of the leading edge vortex in lift augmentation of steadily revolving wings: a change in perspective
Authors: Nabawy Mostafa R. A. , Crowther William J.
Published: July 2017

The presence of a stable leading edge vortex (LEV) on steadily revolving wings increases the maximum lift coefficient that can be generated from the wing and its role is important to understanding natural flyers and flapping wing vehicles. In this paper, the role of LEV in lift augmentation is discussed under two hypotheses referred to as ‘additional lift' and ‘absence of stall’. The ‘additional lift' hypothesis represents the traditional view. It presumes that an additional suction/circulation from the LEV increases the lift above that of a potential flow solution. This behaviour may be represented through either the ‘Polhamus leading edge suction' model or the so-called ‘trapped vortex' model. The ‘absence of stall' hypothesis is a more recent contender that presumes that the LEV prevents stall at high angles of attack where flow separation would normally occur. This behaviour is represented through the so-called ‘normal force' model. We show that all three models can be written in the form of the same potential flow kernel with modifiers to account for the presence of a LEV. The modelling is built on previous work on quasi-steady models for hovering wings such that model parameters are determined from first principles, which allows a fair comparison between the models themselves, and the models and experimental data. We show that the two models which directly include the LEV as a lift generating component are built on a physical picture that does not represent the available experimental data. The simpler ‘normal force' model, which does not explicitly model the LEV, performs best against data in the literature. We conclude that under steady conditions the LEV as an ‘absence of stall’ model/mechanism is the most satisfying explanation for observed aerodynamic behaviour.
A durable and biocompatible ascorbic acid-based covalent coating method of polydimethylsiloxane for dynamic cell culture
Authors: Leivo Joni , Virjula Sanni , Vanhatupa Sari , Kartasalo Kimmo , Kreutzer Joose , Miettinen Susanna , Kallio Pasi
Published: July 2017

Polydimethylsiloxane (PDMS) is widely used in dynamic biological microfluidic applications. As a highly hydrophobic material, native PDMS does not support cell attachment and culture, especially in dynamic conditions. Previous covalent coating methods use glutaraldehyde (GA) which, however, is cytotoxic. This paper introduces a novel and simple method for binding collagen type I covalently on PDMS using ascorbic acid (AA) as a cross-linker instead of GA. We compare the novel method against physisorption and GA cross-linker-based methods. The coatings are characterized by immunostaining, contact angle measurement, atomic force microscopy and infrared spectroscopy, and evaluated in static and stretched human adipose stem cell (hASC) cultures up to 13 days. We found that AA can replace GA as a cross-linker in the covalent coating method and that the coating is durable after sonication and after 6 days of stretching. Furthermore, we show that hASCs attach and proliferate better on AA cross-linked samples compared with physisorbed or GA-based methods. Thus, in this paper, we provide a new PDMS coating method for studying cells, such as hASCs, in static and dynamic conditions. The proposed method is an important step in the development of PDMS-based devices in cell and tissue engineering applications.
Balance control strategies during perturbed and unperturbed balance in standing and handstand
Authors: Blenkinsop Glen M. , Pain Matthew T. G. , Hiley Michael J.
Published: July 2017

Insights into sensorimotor control of balance were examined by the assessment of perturbed and unperturbed balance in standing and handstand postures. During perturbed and unperturbed balance in standing, the most prevalent control strategy was an ankle strategy, which was employed for more than 90% of the time in balance. During perturbed and unperturbed balance in handstand, the most prevalent control strategy was a wrist strategy, which was employed for more than 75% of the time in balance. In both postures, these strategies may be described as a single segment inverted pendulum control strategy, where the multi-segment system is controlled by torque about the most inferior joint with compensatory torques about all superior joints acting in the same direction to maintain a fixed orientation between superior segments. In contrast to previous literature, surprisingly little time was spent in a mixed strategy, representing less than 1% of time in standing balance and approximately 2% of time in handstand balance. Findings indicate that although the central nervous system may employ a number of control strategies during a trial, these strategies are employed individually rather than simultaneously.
Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth
Authors: Gomes Rodrigues Helder , Lefebvre Rémi , Fernández-Monescillo Marcos , Mamani Quispe Bernardino , Billet Guillaume
Published: July 2017

Studying dental ontogeny in mammals can provide valuable insight on the evolution of their masticatory apparatus and their related adaptations. The multiple acquisitions of a prolonged to continuous growth of teeth in herbivorous mammals in response to high abrasion represent an intensively investigated issue. However, the ontogenetic and architectural patterns associated with these repeated dental innovations remain poorly known. Here, we focused on two case studies corresponding to distant mammalian clades, the extinct Mesotheriidae (Notoungulata), which shared some striking dental features with the extant Ctenodactylidae (Rodentia). We studied the impact of prolonged to continuous growth of molars on their occlusal complexity, their relative size and their dynamics in the jaw. We found that variations of occlusal complexity patterns are the result of paedomorphic or peramorphic heterochronic processes impacting dental crown. We showed that variations in both upper and lower molar proportions generally follow the inhibitory developmental cascade model. In that context, prolonged dental growth implies transitory adjustments due to wear, and also involves dental migration and loss when combined with molar lengthening. Interestingly, these features may be present in many mammals having prolonged dental growth, and emphasize the crucial need of considering these aspects in future evolutionary and developmental studies.
Kelp and dolphin gulls cause perineal wounds in South American fur seal pups (
Arctocephalus australis
) at Guafo Island, Chilean Patagonia
Authors: Seguel Mauricio , Muñoz Francisco , Montalva Felipe , Perez-Venegas Diego , Pavés Héctor , Gottdenker Nicole
Published: July 2017

During five reproductive seasons, we documented the presence, extent and origin of perineal wounds in South American fur seal pups (
Arctocephalus australis
) on Guafo Island, Northern Chilean Patagonia. The seasonal prevalence of perineal wounds ranged from 5 to 9%, and new cases were more common at the end of the breeding season (February), when pups were on average two months old and were actively expelling hookworms (
Uncinaria
sp). Histologically, wounds corresponded to marked ulcerative lymphoplasmacytic and histiocytic dermatitis with granulation tissue and mixed bacterial colonies. In 2015 and 2017, kelp gulls (
Larus dominicanus
) and dolphin gulls (
Leucophaeus scoresbii
) were observed picking and wounding the perineal area of marked pups. This behaviour occurred more frequently after the pups' defecation, when sea gulls engaged in consumption of pups' faeces. The affected pups usually had moderate to marked hookworm infections along with bloody diarrhoea and anaemia. Pups with severe wounds (23% of affected animals) had swollen perineal areas and signs of secondary systemic bacterial infection. We propose that seagulls on Guafo Island have learned to consume remains of blood and parasites in the faeces of pups affected by hookworm infection, causing perineal wounds during this process. We conclude that this perineal wounding is an unintentional, occasional negative effect of an otherwise commensal gull–fur seal relationship.
Mathematical and computational modelling of skin biophysics: a review
Authors: Limbert Georges
Published: July 2017

The objective of this paper is to provide a review on some aspects of the mathematical and computational modelling of skin biophysics, with special focus on constitutive theories based on nonlinear continuum mechanics from elasticity, through anelasticity, including growth, to thermoelasticity. Microstructural and phenomenological approaches combining imaging techniques are also discussed. Finally, recent research applications on skin wrinkles will be presented to highlight the potential of physics-based modelling of skin in tackling global challenges such as ageing of the population and the associated skin degradation, diseases and traumas.
Male–female relatedness at specific SNP-linkage groups influences cryptic female choice in Chinook salmon (Oncorhynchus tshawytscha)
Authors: Geßner Cornelia , Johnson Sheri L. , Fisher Paul , Clarke Shannon , Rutherford Kim , Symonds Jane , Gemmell Neil J.
Published: July 2017

In a range of taxa, the relatedness between mates influences both pre- and post-mating processes of sexual selection. However, relatively little is known about the genetic loci facilitating such a bias, with the exception of the major histocompatibility complex. Here, we performed tightly controlled replicatedin vitrofertilization trials to explore the impact of relatedness on two possible mechanisms of cryptic female choice (CFC) in Chinook salmon (Oncorhynchus tshawytscha). We tested (i) whether relatedness of mates, assessed using 682 single nucleotide polymorphisms (SNPs) on 29 SNP-linkage groups (LGs), biases a male's sperm velocity in ovarian fluid (a parameter previously shown to predict male fertilization success), and (ii) whether relatedness of mates governs fertilization success via other mechanisms, probably via sperm–egg interactions. We found that relatedness on three LGs explained the variation in sperm velocity, and relatedness on two LGs explained fertilization success, which might indicate the presence of genes important in sperm–ovarian fluid and sperm–egg interactions in these genomic regions. Mapping of the SNPs on these LGs to the rainbow trout genome revealed two genes that affect fertility in humans and represent candidate genes for further studies. Our results thereby provide a novel contribution to the understanding of the mechanism of CFC.
Oyster reefs as carbon sources and sinks
Authors: Fodrie F. Joel , Rodriguez Antonio B. , Gittman Rachel K. , Grabowski Jonathan H. , Lindquist Niels. L. , Peterson Charles H. , Piehler Michael F. , Ridge Justin T.
Published: July 2017

Carbon burial is increasingly valued as a service provided by threatened vegetated coastal habitats. Similarly, shellfish reefs contain significant pools of carbon and are globally endangered, yet considerable uncertainty remains regarding shellfish reefs' role as sources (+) or sinks (−) of atmospheric CO
2
. While CO
2
release is a by-product of carbonate shell production (then burial), shellfish also facilitate atmospheric-CO
2
drawdown via filtration and rapid biodeposition of carbon-fixing primary producers. We provide a framework to account for the dual burial of inorganic and organic carbon, and demonstrate that decade-old experimental reefs on intertidal sandflats were net sources of CO
2
(7.1 ± 1.2 MgC ha
−1
yr
−1
(µ ± s.e.)) resulting from predominantly carbonate deposition, whereas shallow subtidal reefs (−1.0 ± 0.4 MgC ha
−1
yr
−1
) and saltmarsh-fringing reefs (−1.3 ± 0.4 MgC ha
−1
yr
−1
) were dominated by organic-carbon-rich sediments and functioned as net carbon sinks (on par with vegetated coastal habitats). These landscape-level differences reflect gradients in shellfish growth, survivorship and shell bioerosion. Notably, down-core carbon concentrations in 100- to 4000-year-old reefs mirrored experimental-reef data, suggesting our results are relevant over centennial to millennial scales, although we note that these natural reefs appeared to function as slight carbon sources (0.5 ± 0.3 MgC ha
−1
yr
−1
). Globally, the historical mining of the top metre of shellfish reefs may have reintroduced more than 400 000 000 Mg of organic carbon into estuaries. Importantly, reef formation and destruction do not have reciprocal, counterbalancing impacts on atmospheric CO
2
since excavated organic material may be remineralized while shell may experience continued preservation through reburial. Thus, protection of existing reefs could be considered as one component of climate mitigation programmes focused on the coastal zone.
Adaptation to public goods cheats in
Pseudomonas aeruginosa
Authors: O'Brien Siobhán , Luján Adela M. , Paterson Steve , Cant Michael A. , Buckling Angus
Published: July 2017

Cooperation in nature is ubiquitous, but is susceptible to social cheats who pay little or no cost of cooperation yet reap the benefits. The effect such cheats have on reducing population productivity suggests that there is selection for cooperators to mitigate the adverse effects of cheats. While mechanisms have been elucidated for scenarios involving a direct association between producer and cooperative product, it is less clear how cooperators may suppress cheating in an anonymous public goods scenario, where cheats cannot be directly identified. Here, we investigate the real-time evolutionary response of cooperators to cheats when cooperation is mediated by a diffusible public good: the production of iron-scavenging siderophores by
Pseudomonas aeruginosa
. We find that siderophore producers evolved in the presence of a high frequency of non-producing cheats were fitter in the presence of cheats, at no obvious cost to population productivity. A novel morphotype independently evolved and reached higher frequencies in cheat-adapted versus control populations, exhibiting reduced siderophore production but increased production of pyocyanin—an extracellular toxin that can also increase the availability of soluble iron. This suggests that cooperators may have mitigated the negative effects of cheats by downregulating siderophore production and upregulating an alternative iron-acquisition public good. More generally, the study emphasizes that cooperating organisms can rapidly adapt to the presence of anonymous cheats without necessarily incurring fitness costs in the environment they evolve in.
Multi-functional roles of a soldier-specific volatile as a worker arrestant, primer pheromone and an antimicrobial agent in a termite
Authors: Mitaka Yuki , Mori Naoki , Matsuura Kenji
Published: July 2017

Division of labour in eusocial insects is characterized by efficient communication systems based on pheromones. Among such insects, termites have evolved specialized sterile defenders, called soldiers. Because they are incapable of feeding themselves, it has been suggested that soldiers are sustained by workers and emit the pheromone arresting workers. However, such a soldier pheromone has not been identified in any termite species, and the details of the soldier–worker interaction remain to be explored. Here, we identified a soldier-specific volatile sesquiterpene as a worker arrestant, which also acts as a primer pheromone regulating soldier differentiation and fungistatic agent in a termiteReticulitermes speratus. Chemical analyses revealed that (−)-β-elemene is the major component of soldier extract, and its authentic standard exhibited arrestant activity to workers and inhibited the differentiation from workers to soldiers. This compound also showed fungistatic activity against entomopathogenic fungi. These suggest that (−)-β-elemene secreted by soldiers acts not only as a worker arrestant but also as one component of inhibitory primer pheromone and an anti-pathogenic agent. Our study provides novel evidence supporting the multi-functionality of termite soldier pheromone and provides new insights into the role of soldiers and the evolutionary mechanisms of pheromone compounds.
Communication from learned to innate olfactory processing centers is required for memory retrieval inDrosophila
Authors: Dolan Michael-John , Belliart-Guérin Ghislain , Shakeel Bates Alexander , Aso Yoshinori , Frechter Shahar , Roberts Ruairí J.V. , Schlegel Philipp , Wong Allan , Hammad Adnan , Bock Davi , Rubin Gerald M. , Preat Thomas , Plaçais Pierre-Yves , Jefferis Gregory S.X.E.
Published: July 2017

Animals can show either learned or innate behavioral responses to a given stimulus. How these circuits interact to produce an appropriate behavioral response is unknown. In theDrosophilaolfactory system, the lateral horn (LH) and the mushroom body (MB) are thought to mediate innate and learned olfactory behavior respectively, although the function of the LH has not been directly tested. Here we identify two LH cell-types (PD2a1/b1) that receive input from an MB output neuron required for recall of aversive olfactory memories. In contrast to the model above we find that PD2a1/b1 are required for aversive memory retrieval. PD2a1/b1 activity is modulated by training, indicating that memory information is passed to the innate olfactory processing centre. We map the connectivity of PD2a1/b1 to other olfactory neurons with connectomic data. This provides a circuit mechanism by which learned and unlearned olfactory information can interact to produce appropriate behavior.
Long-term consolidation switches goal proximity coding from hippocampus to retrosplenial cortex
Authors: Patai E. Zita , Javadi Amir-Homayoun , Ozubko Jason D. , O’Callaghan Andrew , Ji Shuman , Robin Jessica , Grady Cheryl , Winocur Gordon , Rosenbaum Shayna R. , Moscovitch Morris , Spiers Hugo J.
Published: July 2017

Recent research indicates the hippocampus may code the distance to the goal during navigation of newly learned environments. It is unclear however, whether this also pertains to highly familiar environments where extensive systems-level consolidation is thought to have transformed mnemonic representations. Here we recorded fMRI while University College London and Imperial College London students navigated virtual simulations of their own familiar campus (> 2 years of exposure) and the other campus learned days before scanning. Posterior hippocampal activity tracked the proximity to the goal in the newly learned campus, but not in the familiar campus. By contrast retrosplenial cortex tracked the distance to the goal in the familiar campus, but not in the recently learned campus. These responses were abolished when participants were guided to their goal by external cues. These results open new avenues of research on navigation and consolidation of spatial information and help advance models of how neural circuits support navigation in novel and highly familiar environments.

Significance Statement

Historically, research on the hippocampal formation has focused on its role in long-term memory and navigation – often in isolation. No study to date has directly compared realistic navigation within familiar with recently learned environments, nor has it been explored how the neural substrates, along with computational codes, may change. In this study, we show for the first time, a shift from hippocampal to cortical coding of distance to a goal during active navigation. This study bridges the gap between memory consolidation and navigation, and paves the way for more functional and realistic understanding of the hippocampus.
A cross-validation-based approach for delimiting reliable home range estimates
Authors: Dougherty Eric R , Carlson Colin J , Blackburn Jason K , Getz Wayne M
Published: July 2017

Background

With decreasing costs of GPS telemetry devices, data repositories of animal movement paths are increasing almost exponentially in size. A series of complex statistical tools have been developed in conjunction with this increase in data. Each of these methods offers certain improvements over previously proposed methods, but each has certain assumptions or shortcomings that make its general application difficult. In the case of the recently developed Time Local Convex Hull (T-LoCoH) method, the subjectivity in parameter selection serves as one of the primary impediments to its more widespread use. While there are certain advantages to the flexibility it offers for question-driven research, the lack of an objective approach for parameter selection may prevent some users from exploring the benefits of the method.

Results

Here we present a cross-validation-based approach for selecting parameter values to optimize the T-LoCoH algorithm. We demonstrate the utility of the approach using a case study from the Etosha National Park anthrax system. Utilizing the proposed algorithm, rather than the guidelines in the T-LoCoH documentation, results in significantly different values for derived site fidelity metrics.

Conclusions

Due to its basis in principles of cross-validation, the application of this method offers a more objective approach than the relatively subjective guidelines set forth in the T-LoCoH documentation and enables a more accurate basis for the comparison of home ranges among individuals and species, as well as among studies.
Imaging action potential in single mammalian neurons by tracking the accompanying sub-nanometer mechanical motion
Authors: Yang Yunze , Liu Xian-Wei , Yu Hui , Guan Yan , Wang Shaopeng , Tao Nongjian
Published: July 2017

Action potentials in neurons have been studied traditionally by the patch clamp and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with sub-nanometer detection limit and sub-millisecond temporal resolution. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2 - 0.4 nm. The work indicates that action potentials may be studied non-invasively in single mammalian neurons by label-free imaging of the accompanying subnanometer mechanical motion.
Secretion of redox-active metabolites as a general strategy for iron acquisition in plants
Authors: Rajniak Jakub , Giehl Ricardo F. , Chang Evelyn , Murgia Irene , von Wirén Nicolaus , Sattely Elizabeth S.
Published: July 2017

Iron is an essential but often poorly bioavailable nutrient due to its low solubility, especially in alkaline soils. Plants have evolved at least two distinct strategies to extract iron from soil: solubilization of ferric iron by phytosiderophores, and reduction to the ferrous form at the root surface followed by direct import. Here, we describe the discovery of a novel redox-active catecholic metabolite, termed sideretin, which derives from the coumarin fraxetin, and is the primary molecule exuded byArabidopsis thalianaroots in response to iron deficiency. Using a combination of metabolomics, heterologous expression, and coexpression analysis we have identified two enzymes that complete the biosynthetic pathway of sideretin. Chemical characterization of synthetic sideretin and biological assays with pathway mutants suggest that sideretin is critical for iron nutrition and support a role for small molecule-mediated iron reduction inA. thalianaunder iron-limiting growth conditions. Further, we show that sideretin production is evolutionarily ancient and occurs in eudicot species only distantly related toA. thaliana. In addition to sideretin, untargeted metabolomics of the root exudates of various eudicots revealed the production of structurally diverse redox-active molecules in response to iron deficiency. Our results indicate that secretion of small molecule reductants by roots may be a widespread and previously underappreciated component of the reduction-based iron uptake strategy.
Probabilistic language models in cognitive neuroscience: promises and pitfalls
Authors: Armeni Kristijan , Willems Roel M. , Frank Stefan
Published: July 2017

Cognitive neuroscientists of language comprehension study how neural computations relate to cognitive computations during comprehension. On the cognitive part of the equation, it is important that the computations and processing complexity are explicitly defined. Probabilistic language models can be used to give a computationally explicit account of language complexity during comprehension. Whereas such models have so far predominantly been evaluated against behavioral data, only recently have the models been used to explain neurobiological signals. Measures obtained from these models emphasize the probabilistic, information-processing view of language understanding and provide a set of tools that can be used for testing neural hypotheses about language comprehension. Here, we provide a cursory review of the theoretical foundations and example neuroimaging studies employing probabilistic language models. We high-light the advantages and potential pitfalls of this approach and indicate avenues for future research.
Dynamic semantic cognition: Characterising coherent and controlled conceptual retrieval through time using magnetoencephalography and chronometric transcranial magnetic stimulation
Authors: Teige Catarina , Mollo Giovanna , Millman Rebecca , Savill Nicola , Smallwood Jonathan , Cornelissen Piers L. , Jefferies Elizabeth
Published: July 2017

Distinct neural processes are thought to support the retrieval of semantic information that is (i) coherent with strongly-encoded aspects of knowledge, and (ii) non-dominant yet relevant for the current task or context. While the brain regions that support coherent and controlled patterns of semantic retrieval are relatively well-characterised, the temporal dynamics of these processes are not well-understood. This study used magnetoencephalography (MEG) and dual-pulse chronometric transcranial magnetic stimulation (cTMS) in two separate experiments to examine temporal dynamics within the temporal lobe during the retrieval of strong and weak associations. MEG results revealed a dissociation within left temporal cortex: anterior temporal lobe (ATL) showed greater oscillatory response for strong than weak associations, while posterior middle temporal gyrus (pMTG) showed the reverse pattern. In the cTMS experiment, stimulation of ATL at ~150ms disrupted the efficient retrieval of strong associations, indicating a necessary role for ATL in coherent conceptual activations. Stimulation of pMTG at the onset of the second word disrupted the retrieval of weak associations, suggesting this site may maintain information about semantic context from the first word, allowing engagement of semantic control. Together these studies provide converging evidence for a functional dissociation within the temporal lobe, across both tasks and time.
Overexpression of Channelrhodopsin 2 interferes with the GABAb receptor-mediated depression of GABA release from the somatostatin-containing interneurons of the prefrontal cortex
Authors: Liu Lei , Ito Wataru , Morozov Alexei
Published: July 2017

Region and cell-type restricted expression of light activated ion channels is the indispensable tool to study properties of synapses in specific circuits and to monitor synaptic alterations by various stimuli including neuromodulators and behaviors, both ex vivo and in vivo. These analyses require the light-activated proteins or viral vectors for their delivery that do not interfere with the phenomenon under study. Here, we report a case of such interference in which the high-level expression of Channelrhodopsin-2 (ChR2) introduced in the somatostatin-positive GABAergic neurons (SOM-INs) of the dorsomedial prefrontal cortex (dmPFC) by an adeno-associated virus vector (AAV) weakens the presynaptic GABAb receptor-mediated suppression of GABA release.
Extracellular monomeric and aggregated tau efficiently enter human neurons through overlapping but distinct pathways
Authors: Wassmer T. , Evans L. , Fraser G. , Smith J. , Perkinton M. , Billinton A. , Livesey F.J.
Published: July 2017

A current working model is that Alzheimer's disease actively spreads from diseased to healthy neurons, mediated by transfer of extracellular, abnormal, disease-specific forms of the microtubule-associated protein tau. It is currently unclear whether transfer of tau between neurons is a toxic gain-of-function process in dementia, or reflects a constitutive biological process. We report two mechanisms of entry of monomeric tau to neurons: a rapid early dynamin-dependent phase, and a second, slower actin-dependent phase, suggesting that monomeric tau enters neurons via rapid saturable clathrin-mediated endocytosis and also by bulk endocytosis. Aggregated tau entry is independent of actin polymerisation and largely dynamin dependent, consistent with clathrin-mediated endocytosis and distinct from macropinocytosis, the major route for aggregated tau entry reported for non-neuronal cells. Anti-tau antibodies abrogate tau entry into neurons, with tau carrying antibody with it into neurons, indicating that antibody binding is insufficient to prevent neuronal tau entry.
Introgression patterns between house mouse subspecies and species reveal genomic windows of frequent exchange
Authors: Ullrich Kristian Karsten , Linnenbrink Miriam , Tautz Diethard
Published: July 2017

Based on whole genome sequencing data, we have studied the patterns of introgression in a phylogenetically well defined set of populations, sub-species and species of mice (Mus m. domesticus,Mus m. musculus,Mus m. castaneusandMus spretus). We find that many discrete genomic regions are subject to repeated and mutual introgression and exchange. The majority of these regions code for genes that are involved in parasite defense or genomic conflict. They include genes involved in adaptive immunity, such as the MHC region or antibody coding regions, but also genes involved in innate immune reactions of the epidermis. We find also clusters of KRAB zinc finger proteins that control the spread of transposable elements and genes that are involved in meiotic drive. These findings suggest that even well separated populations and species maintain the capacity to exchange genetic material in a special set of evolutionary active genes.
Hybrid multiple diffraction in semipolar wurtzite materials: (\bf 01\overline{1}2)-oriented ZnMgO/ZnO heterostructures as an illustration
Authors: de Prado Esther , Martínez-Tomás M. Carmen , Deparis Christiane , Muñoz-Sanjosé Vicente , Zúñiga-Pérez Jesús
Published: July 2017

X-ray diffraction has been widely used to characterize the structural properties (strain and structural quality) of semiconductor heterostructures. This work employs hybrid multiple diffraction to analyzer-oriented Zn1−xMgxO layers grown by molecular beam epitaxy on ZnO substrates. In such a low-symmetry material system, additional features appear in symmetric reflection scans, which are described as arising from hybrid multiple diffraction. First, the Bragg conditions necessary for these high-order processes to occur are introduced and applied to explain all the observed satellite reflections, identify the planes that contribute and computea priorithe angles at which they are observed. Furthermore, thanks to this hybrid multiple-diffraction technique, it is possible to determine the layer lattice parameters (in-plane and out-of-plane) in an easy and accurate way by using one single measurement in standard symmetric conditions. The achieved precision is at least as high as that obtained from the combination of symmetric and asymmetric reciprocal space map measurements.
Electron backscatter diffraction study of orientation gradients at the grain boundaries of a polycrystalline steel sheet deformed along different loading paths
Authors: Signorelli J. W. , Roatta A. , De Vincentis N. , Schwindt C. , Avalos M. , Bolmaro R. E. , Bozzolo N.
Published: July 2017

In a polycrystal, the heterogeneity of plastic deformation in a particular grain is greatly enhanced by adjacent grains that constrain the grain's local behavior, often imposing orientation gradients. This work aims to characterize and quantify the local orientation gradients near grain boundaries (GBs). Electron backscatter diffraction (EBSD) measurements were made on a 0.67 mm thick aluminium-killed drawing quality (AKDQ) steel sheet subjected to different loading paths that are typical of forming operations. A statistical analysis shows that a considerable fraction of the analyzed GB profiles can be described by an orientation profile with a constant slope near the GB. In order to quantify this behavior, as well as the degree of localization, two new parameters, based on the local orientation gradient assessed by EBSD, are proposed: BET (boundary effective thickness) and GAS (gradient average severity). These parameters should be considered together, the BET as an effective thickness of the GB zone where the orientation gradient takes place and the GAS as a measure of the magnitude or severity of the orientation gradient. Additionally, the GAS parameter shows a strong correlation with the accumulated macroscopic strain for the investigated deformation levels and loading paths, while the BET profile clearly reveals the influence of the GB on the misorientation profiles. Tension and biaxial stretching results lead to a BET value between 1.5 and 2 µm. Finally, it is shown that the local misorientation in the GB zone, on both sides of the GB line, is disperse and it does not correlate simply with misorientation or even the slip-transfer geometry across the GB. Moreover, the observed average local misorientation dispersions in GB zones are different for each loading condition.
The quorum-quenching lactonase from Alicyclobacter acidoterrestris: purification, kinetic characterization, crystallization and crystallographic analysis
Authors: Bergonzi Celine , Schwab Michael , Chabriere Eric , Elias Mikael
Published: July 2017

Lactonases comprise a class of enzymes that hydrolyze lactones, including acyl-homoserine lactones (AHLs); the latter are used as chemical signaling molecules by numerous Gram-negative bacteria. Lactonases have therefore been demonstrated to quench AHL-based bacterial communication. In particular, lactonases are capable of inhibiting bacterial behaviors that depend on these chemicals, such as the formation of biofilms or the expression of virulence factors. A novel representative from the metallo-β-lactamase superfamily, named AaL, was isolated from the thermoacidophilic bacterium Alicyclobacter acidoterrestris. Kinetic characterization proves AaL to be a proficient lactonase, with catalytic efficiencies (k
cat/K
m) against AHLs in the region of 105 M
−1 s−1. AaL exhibits a very broad substrate specificity. Its structure is expected to reveal the molecular determinants for its substrate binding and specificity, as well as to provide grounds for future protein-engineering projects. Here, the expression, purification, characterization, crystallization and X-ray diffraction data collection of AaL at 1.65 Å resolution are reported.