bluuebunny/crossref_metadata_2025_split huggingface dataset:
Input-dependent modulation of MEG gamma oscillations reflects gain control in the visual cortex
Authors: Orekhova Elena V. , Sysoeva Olga V. , Schneiderman Justin F. , Lundström Sebastian , Galuta Ilia A. , Goiaeva Dzerasa E. , Prokofyev Andrey O. , Riaz Bushra , Keeler Courtney , Hadjikhani Nouchine , Gillberg Christopher , Stroganova Tatiana A. 
Published: May 2018

AbstractGamma-band oscillations arise from the interplay between neural excitation (E) and inhibition (I) and may provide a non-invasive window into the state of cortical circuitry. A bell-shaped modulation of gamma response power by increasing the intensity of sensory input was observed in animals and is thought to reflect neural gain control. Here we sought to find a similar input-output relationship in humans with MEG via modulating the intensity of a visual stimulation by changing the velocity/temporal-frequency of visual motion. In the first experiment, adult participants observed static and moving gratings. The frequency of the MEG gamma response monotonically increased with motion velocity whereas power followed a bell-shape. In the second experiment, on a large group of children and adults, we found that despite drastic developmental changes in frequency and power of gamma oscillations, the relative suppression at high motion velocities was scaled to the same range of values across the life-span. In light of animal and modeling studies, the modulation of gamma power and frequency at high stimulation intensities characterizes the capacity of inhibitory neurons to counterbalance increasing excitation in visual networks. Gamma suppression may thus provide a non-invasive measure of inhibitory-based gain control in the healthy and diseased brain.
Quantitative analysis of the effect of environmental-scanning electron microscopy on collagenous tissues
Authors: Lee Woowon , Toussaint Kimani C. 
Published: May 2018

AbstractEnvironmental-scanning electron microscopy (ESEM) is routinely applied to various biological samples due to its ability to maintain a wet environment while imaging; moreover, the technique obviates the need for sample coating. However, there is limited research carried out on electron-beam (e-beam) induced tissue damage resulting from using the ESEM. In this paper, we use quantitative second-harmonic generation (SHG) microscopy to examine the effects of e-beam exposure from the ESEM on collagenous tissue samples prepared as either fixed, frozen, wet or dehydrated. Quantitative SHG analysis of tissues, before and after ESEM e-beam exposure in low-vacuum mode, reveals evidence of cross-linking of collagen fibers, however there are no structural differences observed in fixed tissue. Meanwhile wet-mode ESEM appears to radically alter the structure from a regular fibrous arrangement to a more random fiber orientation. We also confirm that ESEM images of collagenous tissues show higher spatial resolution compared to SHG microscopy, but the relative tradeoff with collagen specificity reduces its effectiveness in quantifying collagen fiber organization. Our work provides insight on both the limitations of the ESEM for tissue imaging, and the potential opportunity to use as a complementary technique when imaging fine features in the non-collagenous regions of tissue samples.
Comparative genomic analysis of a naturally competent Elizabethkingia anophelis isolated from an eye infection
Authors: Bulagonda Eswarappa Pradeep , Manivannan Bhavani , Mahalingam Niranjana , Lama Manmath , Chanakya Pachi Pulusu , Khamari Balaram , Jadhao Sudhir , Vasudevan Madavan , Nagaraja Valakunja 
Published: May 2018

AbstractElizabethkingia anophelis has now emerged as an opportunistic human pathogen. However, its mechanisms of transmission remain unexplained. Comparative genomic (CG) analysis of E. anopheles endophthalmitis strain surprisingly found from an eye infection patient with twenty-five other E. anophelis genomes revealed its potential to participate in horizontal gene transfer. CG analysis revealed that the study isolate has an open pan genome and has undergone extensive gene rearrangements. We demonstrate that the strain is naturally competent, hitherto not reported in any members of Elizabethkingia. Presence of competence related genes, mobile genetic elements, Type IV, VI secretory systems and a unique virulence factor arylsulfatase suggests a different lineage of the strain. Deciphering the genome of E. anophelis having a reservoir of antibiotic resistance genes and virulence factors associated with diverse human infections may open up avenues to deal with the myriad of its human infections and devise strategies to combat the pathogen.
GWAS reveals loci associated with velopharyngeal dysfunction
Authors: Chernus Jonathan , Roosenboom Jasmien , Ford Matthew , Lee Myoung Keun , Emanuele Beth , Anderton Joel , Hecht Jacqueline T. , Padilla Carmencita , Deleyiannis Frederic W. B. , Buxo Carmen J. , Feingold Eleanor , Leslie Elizabeth J. , Shaffer John R. , Weinberg Seth M. , Marazita Mary L. 
Published: May 2018

AbstractVelopharyngeal dysfunction (VPD) occurs when the muscular soft palate (velum) and lateral pharyngeal walls are physically unable to separate the oral and nasal cavities during speech production leading to hypernasality and abnormal speech reduction. Because VPD is often associated with overt or submucous cleft palate, it could be present as a subclinical phenotype in families with a history of orofacial clefting. A key assumption to this model is that the overt and subclinical manifestations of the orofacial cleft phenotype exist on a continuum and therefore share common etiological factors. We performed a genome-wide association study in 976 unaffected relatives of isolated CP probands, 54 of whom had VPD. Five loci were significantly (p < 5 × 10−8) associated with VPD: 3q29, 9p21.1, 12q21.31, 16p12.3 and 16p13.3. An additional 15 loci showing suggestive evidence of association with VPD were observed. Several genes known to be involved in orofacial clefting and craniofacial development are located in these regions, such as TFRC, PCYT1A, BNC2 and FREM1. Although further research is necessary, this could be an indication for a potential shared genetic architecture between VPD and cleft palate, and supporting the hypothesis that VPD is a subclinical phenotype of orofacial clefting.
A regionally-adapted implementation of conservation agriculture delivers rapid improvements to soil properties associated with crop yield stability
Authors: Williams Alwyn , Jordan Nicholas R. , Smith Richard G. , Hunter Mitchell C. , Kammerer Melanie , Kane Daniel A. , Koide Roger T. , Davis Adam S. 
Published: May 2018

AbstractClimate models predict increasing weather variability, with negative consequences for crop production. Conservation agriculture (CA) may enhance climate resilience by generating certain soil improvements. However, the rate at which these improvements accrue is unclear, and some evidence suggests CA can lower yields relative to conventional systems unless all three CA elements are implemented: reduced tillage, sustained soil cover, and crop rotational diversity. These cost-benefit issues are important considerations for potential adopters of CA. Given that CA can be implemented across a wide variety of regions and cropping systems, more detailed and mechanistic understanding is required on whether and how regionally-adapted CA can improve soil properties while minimizing potential negative crop yield impacts. Across four US states, we assessed short-term impacts of regionally-adapted CA systems on soil properties and explored linkages with maize and soybean yield stability. Structural equation modeling revealed increases in soil organic matter generated by cover cropping increased soil cation exchange capacity, which improved soybean yield stability. Cover cropping also enhanced maize minimum yield potential. Our results demonstrate individual CA elements can deliver rapid improvements in soil properties associated with crop yield stability, suggesting that regionally-adapted CA may play an important role in developing high-yielding, climate-resilient agricultural systems.
Prioritizing monitoring and conservation efforts for fish spawning aggregations in the U.S. Gulf of Mexico
Authors: Grüss Arnaud , Biggs Christopher , Heyman William D. , Erisman Brad 
Published: May 2018

AbstractIn the U.S. Gulf of Mexico (U.S. GOM), the identification and characterization of transient fish spawning aggregation (FSA) sites is recognized as a regional priority for conservation, but progress is hindered by a lack of understanding of FSA distributions for most exploited species. We employed information compiled in regional databases on FSAs and monitoring for the U.S. GOM to fit species distribution models and produce maps showing the areas likely to host single- and multi-species transient FSA sites. Our results revealed two distinct regions of the U.S. GOM for prioritizing monitoring and conservation efforts for transient FSAs: the coastal waters surrounding major bay systems, particularly those of Texas and Louisiana, and portions of the continental shelf edge (the Flower Garden Banks area and the West Florida shelf edge). The next step would be to locate and characterize actual transient FSA sites in the U.S. GOM by surveying within the areas we identified.
Photonic machine learning implementation for signal recovery in optical communications
Authors: Argyris Apostolos , Bueno Julián , Fischer Ingo 
Published: May 2018

AbstractMachine learning techniques have proven very efficient in assorted classification tasks. Nevertheless, processing time-dependent high-speed signals can turn into an extremely challenging task, especially when these signals have been nonlinearly distorted. Recently, analogue hardware concepts using nonlinear transient responses have been gaining significant interest for fast information processing. Here, we introduce a simplified photonic reservoir computing scheme for data classification of severely distorted optical communication signals after extended fibre transmission. To this end, we convert the direct bit detection process into a pattern recognition problem. Using an experimental implementation of our photonic reservoir computer, we demonstrate an improvement in bit-error-rate by two orders of magnitude, compared to directly classifying the transmitted signal. This improvement corresponds to an extension of the communication range by over 75%. While we do not yet reach full real-time post-processing at telecom rates, we discuss how future designs might close the gap.
Thermooptical evidence of carrier-stabilized ferroelectricity in ultrathin electrodeless films
Authors: Pacherova O. , Chvostova D. , Kocourek T. , Jelinek M. , Dejneka A. , Eliseev E. , Morozovska A. , Tyunina M. 
Published: May 2018

AbstractFerroelectric films may lose polarization as their thicknesses decrease to a few nanometers because of the depolarizing field that opposes the polarization therein. The depolarizing field is minimized when electrons or ions in the electrodes or the surface/interface layers screen the polarization charge or when peculiar domain configuration is formed. Here, we demonstrate ferroelectric phase transitions using thermooptical studies in ∼5-nm-thick epitaxial Pb0.5Sr0.5TiO3 films grown on different insulating substrates. By comparing theoretical modeling and experimental observations, we show that ferroelectricity is stabilized through redistribution of charge carriers (electrons or holes) inside ultrathin films. The related high-density of screening carriers is confined within a few-nanometers-thick layer in the vicinity of the insulator, thus resembling a two-dimensional carrier gas.
Glutamate mediated metabolic neutralization mitigates propionate toxicity in intracellular Mycobacterium tuberculosis
Authors: Lee Jae Jin , Lim Juhyeon , Gao Shengjia , Lawson Christopher P. , Odell Mark , Raheem Saki , Woo JeongIm , Kang Sung-Ho , Kang Shin-Seok , Jeon Bo-Young , Eoh Hyungjin 
Published: May 2018

AbstractMetabolic networks in biological systems are interconnected, such that malfunctioning parts can be corrected by other parts within the network, a process termed adaptive metabolism. Unlike Bacillus Calmette-Guérin (BCG), Mycobacterium tuberculosis (Mtb) better manages its intracellular lifestyle by executing adaptive metabolism. Here, we used metabolomics and identified glutamate synthase (GltB/D) that converts glutamine to glutamate (Q → E) as a metabolic effort used to neutralize cytoplasmic pH that is acidified while consuming host propionate carbon through the methylcitrate cycle (MCC). Methylisocitrate lyase, the last step of the MCC, is intrinsically downregulated in BCG, leading to obstruction of carbon flux toward central carbon metabolism, accumulation of MCC intermediates, and interference with GltB/D mediated neutralizing activity against propionate toxicity. Indeed, vitamin B12 mediated bypass MCC and additional supplement of glutamate led to selectively correct the phenotypic attenuation in BCG and restore the adaptive capacity of BCG to the similar level of Mtb phenotype. Collectively, a defective crosstalk between MCC and Q → E contributes to attenuation of intracellular BCG. Furthermore, GltB/D inhibition enhances the level of propionate toxicity in Mtb. Thus, these findings revealed a new adaptive metabolism and propose GltB/D as a synergistic target to improve the antimicrobial outcomes of MCC inhibition in Mtb.
Piezoelectricity and valley chern number in inhomogeneous hexagonal 2D crystals
Authors: Rostami Habib , Guinea Francisco , Polini Marco , Roldán Rafael 
Published: May 2018

AbstractConversion of mechanical forces to electric signal is possible in non-centrosymmetric materials due to linear piezoelectricity. The extraordinary mechanical properties of two-dimensional materials and their high crystallinity make them exceptional platforms to study and exploit the piezoelectric effect. Here, the piezoelectric response of non-centrosymmetric hexagonal two-dimensional crystals is studied using the modern theory of polarization and k·p model Hamiltonians. An analytical expression for the piezoelectric constant is obtained in terms of topological quantities, such as the valley Chern number. The theory is applied to semiconducting transition metal dichalcogenides and hexagonal Boron Nitride. We find good agreement with available experimental measurements for MoS2. We further generalize the theory to study the polarization of samples subjected to inhomogeneous strain (e.g., nanobubbles). We obtain a simple expression in terms of the strain tensor, and show that charge densities ≳1011cm−2 can be induced by realistic inhomogeneous strains, ϵ ≈ 0.01–0.03.
Assessment of groundwater quality in the Al- Burayhi and Hedran sub-basin, Taiz, Yemen – A GIS approach
Authors: Naser Ramzy , El Bakkali Mohammed , Darwesh Nabil , El Kharrim Khadija , Belghyti Driss 
Published: May 2018

In many parts of the world, groundwater sources are the single most important supply for the production of drinking water, particularly in areas with limited or polluted surface water sources. Fresh water has become a scarce commodity due to over exploitation and pollution of water. Many countries and international organizations, including Wolrd Health Organization, are seeking to promote people's access to safe drinking water. The situation in Yemen is no exception. Although we rely on groundwater significantly in our lives and our survival, we do not manage it in a way that ensures its sustainability and maintenance of pollution.
The objective of this study is to determine the suitability of the groundwater in Al Burayhi and Hedran sub-basin (one of the sub-basins of the Upper Valley Rasyan) as a source of drinking water in the shade of the expected deterioration due to natural processes (water interaction with rocks, semi-dry climate) and human activities.
Development of a technique for the real-time determination of crack geometries in laboratory samples
Authors: M Buss Thomas , P Rouse James , J Hyde Christopher , D Garvey Seamus 
Published: May 2018

Crack size determination using electrical potentials both in service and in the laboratory has been undertaken for many years. In the laboratory this has mainly concentrated on the measurement of crack depth, with either alternating current (AC) or direct current (DC) supplies. Some work to determine the varying depth along the width of cracks as an inspection tool of in service parts using mapping methods has been done. This has used both AC and DC utilising various models to understand the data recorded, in Alternating Current Potential Drop (ACPD) a range of frequencies have been used to give various skin depths.
The resulting analyses have been grouped into two groups 'thin skin' and 'thick skin', in the thin skin case the skin depth is significantly smaller than the depth of the crack 1/10th of the crack depth whereas in the thick skin cases are for cases where skin depth is over this limit. Some work has been carried out to try and unify these two approaches.
The work presented here looks to develop a method using variable frequency ACPD to resolve further information about cracks growing in laboratory specimens. A system has been developed to rapidly sweep a wide frequency band and record voltage drop across a crack or feature. A selection of steel samples with known geometries and features have been used to trial and benchmark the technique. These samples have a range of cross sections as well as machined features or a range of shapes and sizes to simulate a range of crack geometries. This work has been approximated using a 2D computational model. This has been done using a reduced thickness approach.
The relevance of non-stationarities and non-Gaussianities in vibration fatigue
Authors: Česnik Martin , Slavič Janko , Capponi Lorenzo , Palmieri Massimiliano , Cianetti Filippo , Boltežar Miha 
Published: May 2018

In classical fatigue of materials, the frequency contents of dynamic loading are well below the natural frequencies of the observed structure or test specimen. However, when dealing with vibration fatigue the frequency contents of dynamic loading and structure's dynamic response overlap, resulting in amplified stress loads of the structure. For such cases, frequency counting methods are especially convenient. Gaussianity and stationarity assumptions are applied in frequency-domain methods for obtaining dynamic structure's response and frequency-domain methods for calculating damage accumulation rate. Since it is common in real environments for the structure to be excited with non-Gaussian and non-stationary loads, this study addresses the effects of such dynamic excitation to experimental time-to-failure of a structure.
Initially, the influence of non-Gaussian stationary excitation is experimentally studied via excitation signals with equal power density spectrum and different values of kurtosis. Since no relevant changes of structure's time-to-failure were observed, the study focused on non-stationary excitation signals that are also inherently non-Gaussian. The non-stationarity of excitation was achieved by amplitude modulation and significantly shorter times-to-failure were observed when compared to experiments with stationary non-Gaussian excitation.
Additionally, the structure's time-to-failure varied with the rate of the amplitude modulation. To oversee this phenomenon the presented study proposes a non-stationarity index which can be obtained from the excitation time history. The non-stationarity index was experimentally confirmed as a reliable estimator for severity of non-stationary excitation. The non-stationarity index is used to determine if the frequencydomain methods can safely be applied for time-to-failure calculation.
Carbon dioxide versus air insufflation enteroscopy: a systematic review and meta-analysis based on randomized controlled trials
Authors: Aquino Julio , Bernardo Wanderley , de Moura Diogo , Morita Flávio , Rocha Rodrigo , Minata Maurício , Coronel Martin , Rodela Gustavo , Ishida Robson , Kuga Rogério , de Moura Eduardo 
Published: May 2018

Abstract
Objectives To compare the insufflation of CO2 and ambient air in enteroscopy.
Search sources The investigators researched the electronic databases MedLine, Cochrane Library, Central, LILACS, BVS, Scopus and Cinahl. The grey search was conducted in the base of theses of the University of São Paulo, books of digestive endoscopy and references of selected articles and in previous systematic revisions.
Study eligibility criteria The evaluation of eligibility was performed independently, in a non-blind manner, by two reviewers, firstly by title and abstract, followed by complete text. Disagreements between the reviewers were resolved by consensus.
Data collection and analysis method Through the spreadsheet of data extraction, where one author extracted the data and a second author checked the extraction. Disagreements were resolved by debate between the two reviewers. The quality analysis of the studies was performed using the Jadad score. The software RevMan 5 version 5.3 was used for the meta-analysis.
Results Four randomized clinical trials were identified, totaling 473 patients submitted to enteroscopy and comparing insufflation of CO2 and ambient air. There was no statistical difference in the intubation depth between the two groups. When CO2 insufflation was reduced, there was a significant difference in pain levels 1 hour after the procedure (95 % IC, –2.49 [–4.72, –0.26], P: 0.03, I2: 20%) and 3 hours after the procedure (95% IC, –3.05 [–5.92, –0.18], P: 0.04, I2: 0 %). There was a usage of lower propofol dosage in the CO2 insufflation group, with significant difference (95 % IC, –67.68 [–115.53, –19.84], P: 0.006, I2: 0 %). There was no significant difference between the groups in relation to the use of pethidine and to the oxygen saturation.
Limitations Restricted number of randomized clinical trials and nonuniformity of data were limitations to the analysis of the outcomes.
Conclusion The use of CO2 as insufflation gas in enteroscopy reduces the pain levels 1 hour and 3 hours after the procedure, in addition to the reduction of the sedation (propofol) dosage used.
Endoscopic electrochemotherapy for esophageal cancer: a phase I clinical study
Authors: Egeland Charlotte , Baeksgaard Lene , Johannesen Helle , Löfgren Johan , Plaschke Christina , Svendsen Lars , Gehl Julie , Achiam Michael 
Published: May 2018

Abstract
Background and study aims Esophageal cancer is on the rise in the western world and the disease has a poor 5-year survival prognosis below 20 %. Electrochemotherapy is a treatment where a chemotherapeutic drug is combined with locally applied electrical pulses, in order to increase the drug’s cytotoxicity in malignant cells. This study presents the first results with electrochemotherapy treatment in esophageal cancer.
Patients and methods In this first-in-human trial, six patients with advanced esophageal cancer were treated with electrochemotherapy using intravenous bleomycin. All side effects and adverse events (AEs) were registered and the patients were later evaluated with gastroscopy and 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI).
Results Treatment were well tolerated, main AEs being nausea, vomiting, oral thrush, pneumonia, retrosternal pain, fever, and hoarseness. No serious complications were observed. Five patients had a visual tumor response confirmed by gastroscopy. In two cases, these findings were confirmed with 18F-FDG PET/MRI as it revealed a reduction of total tumor mass.
Conclusion Electrochemotherapy in patients with advanced esophageal cancer was conducted without major safety concerns. This study paves the way for larger studies, which may further elucidate response rates for and side effects of this new treatment.