bluuebunny/crossref_metadata_2025 huggingface dataset:
Facies and evolution of the carbonate factory during the Permian–Triassic crisis in South Tibet, China
Authors: Li Mingtao , Song Haijun , Woods Adam D. , Dai Xu , Wignall Paul B.
Published: April 2019

The nature of Phanerozoic carbonate factories is strongly controlled by the composition of carbonate‐producing faunas. During the Permian–Triassic mass extinction interval there was a major change in tropical shallow platform facies: Upper Permian bioclastic limestones are characterized by benthic communities with significant richness, for example, calcareous algae, fusulinids, brachiopods, corals, molluscs and sponges, while lowermost Triassic carbonates shift to dolomicrite‐dominated and bacteria‐dominated microbialites in the immediate aftermath of the Permian–Triassic mass extinction. However, the spatial–temporal pattern of carbonates distribution in high latitude regions in response to the Permian–Triassic mass extinction has received little attention. Facies and evolutionary patterns of a carbonate factory from the northern margin of peri‐Gondwana (palaeolatitude ca 40°S) are presented here based on four Permian–Triassic boundary sections that span proximal, inner to distal, and outer ramp settings from South Tibet. The results show that a cool‐water bryozoan‐dominated and echinoderm‐dominated carbonate ramp developed in the Late Permian in South Tibet. This was replaced abruptly, immediately after the Permian–Triassic mass extinction, by a benthic automicrite factory with minor amounts of calcifying metazoans developed in an inner/middle ramp setting, accompanied by transient subaerial exposure. Subsequently, an extensive homoclinal carbonate ramp developed in South Tibet in the Early Triassic, which mainly consists of homogenous dolomitic lime mudstone/wackestone that lacks evidence of metazoan frame‐builders. The sudden transition from a cool‐water, heterozoan dominated carbonate ramp to a warm‐water, metazoan‐free, homoclinal carbonate ramp following the Permian–Triassic mass extinction was the result of the combination of the loss of metazoan reef/mound builders, rapid sea‐level changes across Permian–Triassic mass extinction and profound global warming during the Early Triassic.
Determinants of Social Networks in Rural China: Does Transportation Have a Role to Play?
Authors: Xiong Ailun , Sun Xianhua , Li Hongyi , Westlund Hans
Published: April 2019

Objectives

In recent years, the origins and sources of social networks and social capital have been extensively studied. Previous studies have primarily focused on social demographic factors. To enrich our understanding of the determinants of social networks, this article explores the role of mobility in rural China.

Methods

Drawing upon a data set from the Chinese General Social Survey, this article first uses clustered effect logit models and then adopts a propensity score matching (PSM) model for a robustness check.

Results

The results demonstrate that citizens who have access to more advanced transportation modes and spend less time on traveling are more likely to establish weak ties, especially with nonagricultural citizens in prestigious job positions. The results also indicate that strong family ties are not the consequence of mobility. By disaggregating the full sample, this article further reveals that the young, rich, and female citizens reap more benefit from mobility.

Conclusions

Given the great importance of automobiles for strengthening social networks, this article suggests that car sharing/pooling/lifting programs might be a viable solution to social network deficits in rural areas.
The assembly of (+)‐vincadifformine‐ and (−)‐tabersonine‐derived monoterpenoid indole alkaloids in Catharanthus roseus involves separate branch pathways
Authors: Williams Danielle , Qu Yang , Simionescu Razvan , De Luca Vincenzo
Published: April 2019

The biological activity of monoterpenoid indole alkaloids (MIAs) has led to their use in cancer treatment and other medical applications. Their biosynthesis has involved the formation of reactive intermediates by responsible enzymes to elaborate several different chemical scaffolds. Modification of scaffolds through different substitution reactions has produced chemically diverse MIAs and related biological activities. The present study characterizes the three‐step pathway involved in the formation of (+)‐echitovenine, the major O‐acetylated MIA of Catharanthus roseus roots, and differentiates it from a parallel pathway involved in the formation of hörhammericine. Separate hydrolases convert a common reactive MIA intermediate to aspidosperma skeletons of opposite specific rotations, that is (+)‐vincadifformine and (−)‐tabersonine, respectively. The formation of (+) minovincinine from (+) vincadifformine 19‐hydroxylase (V19H) is catalyzed by a root‐specific cytochrome P450 with high amino acid sequence similarity to the leaf‐specific tabersonine‐3‐hydroxylase involved in vindoline biosynthesis. Similarly, O‐acetylation of (+)‐minovincinine to form (+) echitovenine involves minovincinine‐O‐acetytransferase. The substrate specificity of V19H and MAT for their respective (+)‐enantiomers defines the separate enantiomer‐specific pathway involved in (+)‐echitovenine biosynthesis and differentiates it from a parallel (−)‐enantiomer‐specific pathway involved in the formation of hörhammericine from (−)‐tabersonine.
The MYB transcription factor Emission of Methyl Anthranilate 1 stimulates emission of methyl anthranilate from Medicago truncatula hairy roots
Authors: Pollier Jacob , De Geyter Nathan , Moses Tessa , Boachon Benoît , Franco‐Zorrilla José M. , Bai Yuechen , Lacchini Elia , Gholami Azra , Vanden Bossche Robin , Werck‐Reichhart Danièle , Goormachtig Sofie , Goossens Alain
Published: April 2019

Plants respond to herbivore or pathogen attacks by activating specific defense programs that include the production of bioactive specialized metabolites to eliminate or deter the attackers. Volatiles play an important role in the interaction of a plant with its environment. Through transcript profiling of jasmonate‐elicited Medicago truncatula cells, we identified Emission of Methyl Anthranilate (EMA) 1, a MYB transcription factor that is involved in the emission of the volatile compound methyl anthranilate when expressed in M. truncatula hairy roots, giving them a fruity scent. RNA sequencing (RNA‐Seq) analysis of the fragrant roots revealed the upregulation of a methyltransferase that was subsequently characterized to catalyze the O‐methylation of anthranilic acid and was hence named M. truncatula anthranilic acid methyl transferase (MtAAMT) 1. Given that direct activation of the MtAAMT1 promoter by EMA1 could not be unambiguously demonstrated, we further probed the RNA‐Seq data and identified the repressor protein M. truncatula plant AT‐rich sequence and zinc‐binding (MtPLATZ) 1. Emission of Methyl Anthranilate 1 binds a tandem repeat of the ACCTAAC motif in the MtPLATZ1 promoter to transactivate gene expression. Overexpression of MtPLATZ1 in transgenic M. truncatula hairy roots led to transcriptional silencing of EMA1, indicating that MtPLATZ1 may be part of a negative feedback loop to control the expression of EMA1. Finally, application of exogenous methyl anthranilate boosted EMA1 and MtAAMT1 expression dramatically, thus also revealing a positive amplification loop. Such positive and negative feedback loops seem to be the norm rather than the exception in the regulation of plant specialized metabolism.
The poly(A) polymerase PAPS1 interacts with the RNA‐directed DNA‐methylation pathway in sporophyte and pollen development
Authors: Zhang Yunming , Ramming Anna , Heinke Lisa , Altschmied Lothar , Slotkin R. Keith , Becker Jörg D. , Kappel Christian , Lenhard Michael
Published: April 2019

RNA‐based processes play key roles in the regulation of eukaryotic gene expression. This includes both the processing of pre‐mRNAs into mature mRNAs ready for translation and RNA‐based silencing processes, such as RNA‐directed DNA methylation (RdDM). Polyadenylation of pre‐mRNAs is one important step in their processing and is carried out by three functionally specialized canonical nuclear poly(A) polymerases in Arabidopsis thaliana. Null mutations in one of these, termed PAPS1, result in a male gametophytic defect. Using a fluorescence‐labelling strategy, we have characterized this defect in more detail using RNA and small‐RNA sequencing. In addition to global defects in the expression of pollen‐differentiation genes, paps1 null‐mutant pollen shows a strong overaccumulation of transposable element (TE) transcripts, yet a depletion of 21‐ and particularly 24‐nucleotide‐long short interfering RNAs (siRNAs) and microRNAs (miRNAs) targeting the corresponding TEs. Double‐mutant analyses support a specific functional interaction between PAPS1 and components of the RdDM pathway, as evident from strong synergistic phenotypes in mutant combinations involving paps1, but not paps2 paps4, mutations. In particular, the double‐mutant of paps1 and rna‐dependent rna polymerase 6 (rdr6) shows a synergistic developmental phenotype disrupting the formation of the transmitting tract in the female gynoecium. Thus, our findings in A. thaliana uncover a potentially general link between canonical poly(A) polymerases as components of mRNA processing and RdDM, reflecting an analogous interaction in fission yeast.
A unified DNA sequence and non‐DNA sequence mapping model of complex traits
Authors: Zeng Yanru , Zhu Xuli , Chen Chixiang , Banerjee Kalins , Sun Lidan , Yu Weiwu , Zheng Bingsong , Wu Rongling
Published: April 2019

Summary

Increasing evidence shows that quantitative inheritance is based on both DNA sequence and non‐DNA sequence variants. However, how to simultaneously detect these variants from a mapping study has been unexplored, hampering our effort to illustrate the detailed genetic architecture of complex traits. We address this issue by developing a unified model of quantitative trait locus (QTL) mapping based on an open‐pollinated design composed of randomly sampling maternal plants from a natural population and their half‐sib seeds. This design forms a two‐level hierarchical platform for a joint linkage‐linkage disequilibrium analysis of population structure. The EM algorithm was implemented to estimate and test DNA sequence‐based effects and non‐DNA sequence‐based effects of QTLs. We applied this model to analyze genetic mapping data from the OP design of a gymnosperm coniferous species, Torreya grandis, identifying 25 significant DNA sequence and non‐DNA sequence QTLs for seedling height and diameter growth in different years. Results from computer simulation show that the unified model has good statistical properties and is powerful for QTL detection. Our model enables the tests of how a complex trait is affected differently by DNA‐based effects and non‐DNA sequence‐based transgenerational effects, thus allowing a more comprehensive picture of genetic architecture to be charted and quantified.
np2QTL: networking phenotypic plasticity quantitative trait loci across heterogeneous environments
Authors: Ye Meixia , Jiang Libo , Chen Chixiang , Zhu Xuli , Wang Ming , Wu Rongling
Published: April 2019

Despite its critical importance to our understanding of plant growth and adaptation, the question of how environment‐induced plastic response is affected genetically remains elusive. Previous studies have shown that the reaction norm of an organism across environmental index obeys the allometrical scaling law of part‐whole relationships. The implementation of this phenomenon into functional mapping can characterize how quantitative trait loci (QTLs) modulate the phenotypic plasticity of complex traits to heterogeneous environments. Here, we assemble functional mapping and allometry theory through Lokta−Volterra ordinary differential equations (LVODE) into an R‐based computing platform,np2QTL, aimed to map and visualize phenotypic plasticityQTLs. Based onLVODEparameters,np2QTLconstructs a bidirectional, signed and weighted network ofQTL−QTLepistasis, whose emergent properties reflect the ecological mechanisms for genotype−environment interactions over any range of environmental change. The utility ofnp2QTLwas validated by comprehending the genetic architecture of phenotypic plasticity via the reanalysis of published plant height data involving 3502 recombinant inbred lines of maize planted in multiple discrete environments.np2QTLalso provides a tool for constructing a predictive model of phenotypic responses in extreme environments relative to the median environment.
Research on Flipped Classroom Instructional Design Oriented the Cultivation of Subject Consciousness
Authors: Xiulin Ma , Jing Liang , Sheng Li , Jingjing Liu
Published: April 2019

The information age puts forward higher requirements for talent cultivation, and talents with independent learning concept and innovative spirit are urgently needed. As an activity of cultivating people, education plays an important role in promoting students' participation and cultivating students' subject consciousness, while Flipped Classroom provides a new way for that. This study combines the cultivation of subject consciousness with the practice of Flipped Classroom. Firstly, by analyzing the literature, three dimensions of subject consciousness are concluded: self-consciousness, social consciousness and practice consciousness, and the activities, strategies and evaluation of flipped teaching are designed. Then, the flipped mode and instructional design are applied to the teaching of public computer courses, which experienced two rounds of teaching practice. Finally, by comparing the experimental group with the control group and the longitudinal comparison of the time series, it is found that the flipped mode can effectively stimulate students' subject consciousness, and there is an obvious symbiotic relationship between the students' subject consciousness and performance; and it forms the strategy and effective model of cultivating students' subject consciousness.
Micro, Meso and Macro Levels of Social Analysis
Authors: Serpa Sandro , Ferreira Carlos Miguel
Published: April 2019

Micro, meso and macro are levels or scales that can and may be mobilised in social analysis. This paper aims to contribute to the reflection and discussion, in particular, of the use of the meso level in the apprehension of social reality, in its potential advantages and disadvantages. For this purpose, a document collection and selection was carried out. Furthermore, the authors’ experience in teaching and research in social sciences, especially in the area of Sociology, was also used. This analytical exercise allows concluding that the meso-social level is mobilised in some perspectives, focusing in a privileged way on the group or the organisation as a structure and intermediate process between the other two levels. As for implications, it may be asserted that the meso level only has heuristic capabilities in the interpretation of a particular social context if the other two levels are not neglected in the analysis.
The Impacts of Elastic Band Training on the Posterior Abdominal Wall Muscles of Olympic-Style Weightlifters
Authors: Erdağı Kenan , Poyraz Necdet , Bahar Sadullah , Işık Bülent
Published: April 2019

Purpose: In this study, it was aimed to examine the impacts of elastics band trainings, which were applied for 12 weeks on the Olympic-style weightlifters, on their sportive performances and psoas, ilacus, and quadratus lumborum muscle volumes.Materials and Methods: This research study was conducted on 4 groups, comprising of 12 men (elastic band training group (n=6), control group (n=6)), and 12 women (elastic band training group (n=6), control group (n=6)) Olympic-style weightlifters. The athletes in the elastic band training groups were engaged in standing hip flexion exercises, clamshell exercises, lying hip flexion exercises, and side bend exercises. Before and after the elastic band training applied to the Olympic-style weightlifters for 12 weeks, (1.5 Tesla) MRI device was used for the axial images of the regions starting from the 12th thoracic vertebrae to the trochanter minor of femur. The volume calculations of the muscles were conducted via the Cavalieri method.Results: After the elastic band training, it was determined that the total volume of posterior abdominal wall muscles of the men and women weightlifters in the elastic band training groups and the total weights lifted by them were higher compared to those of the control group individuals (p<0,001).Conclusion: As the result, it can be stated that including the posterior abdominal wall muscle developing trainings into the general programs of the weightlifters in the Olympic weightlifting sport can both enable an increase in the volumes of the muscles in this region and positively influence the performance of the athletes.
Judgments and Prejudices of Students against Their Failure in the Social Studies Class
Authors: Çatak Muzaffer
Published: April 2019

It is necessary to determine the ways of success in order to achieve success. It can be said that it is essential to be aware of the factors that may cause failure to achieve success. Some students have certain prejudices against their classes. This study aims to reveal the prejudice and negative judgments which are thought to affect the failures of students in the social studies class and to establish a solution by determining the prescribed prejudices and judgments that affect students' failures in the relevant class. In addition, as a result of this research, the students who regarded their failure in the social studies class as fundamentally teacher-based indicated it with 138 frequencies in 9 different coding, as self-based with 229 frequencies in 14 different coding and as program-based with 94 frequencies in 4 different coding. It has been seen that the students prioritized themselves more in comparison to the teacher-based and program-based considering the coding varieties and frequency numbers. It can be stated that the students regarded the program as the source of their failure the least.
Analysis of Amateur Soccer Players’ Leadership Levels in Terms of Their Positions
Authors: Ermiş Egemen
Published: April 2019

The purpose of this study is to examine the leadership characteristics of amateur soccer players in terms of positions and some variables. 300 amateur soccer players playing in different clubs in the districts and the city centre of the province of Samsun were included in the study. A personal information form was given to subjects to find out their positions and some variables and Leadership Scale for Sport which was developed by Chelladurai and Saleh (1980) and which included 40 items and five subscales (training and instruction, democratic behaviour, social support, positive feedback and autocratic behaviour) was used to find out leadership levels. SPSS 22.0 program was used in the statistical analysis of the study. When the results of the study were examined, statistically significant difference was found only in positive feedback subscale when the subjects’ leadership levels were compared according to age groups and education levels (p<0.05), while no significance was found in other subscales (p>0.05). When leadership levels were compared in terms of the total period of time they played soccer, their positions, the number of clubs they played for and the state of being the captain, no statistical significance was found in all of the subscales (p>0.05). As a conclusion, it can be seen that leadership levels of soccer players did not differ according to positions, the state of being the captain, the total period of time they played soccer and the number of clubs they played for, while positive feedback was found to develop positively only as age and the state of education increased.
The Effects of Sport Education and Fine Arts Education on Social Appearance Anxiety
Authors: Ermiş Egemen , Imamoğlu Gülten
Published: April 2019

The purpose of this study is to compare the social appearance anxiety levels of university students studying in different fields. Social appearance anxiety scales which were filled in by 481 students were assessed in the study. T-test and one way ANOVA were used for statistical analysis, while LSD tests were used to find out differences.Social appearance anxiety scale scores were found to be higher in male students when compared with female students. No statistically significant difference was found between social appearance anxiety scale scores in terms of genders (p>0.05). In terms of field of education, social appearance anxiety scale scores of students receiving sport education were found to be lower than the scores of students receiving art and music education and the highest social appearance anxiety scale scores were found in students in the department of educational sciences. Statistically significant difference was found between social appearance anxiety scale scores in terms of field of education (p<0.001).As a conclusion, it was found that sport education caused a higher decrease in social appearance anxiety when compared with fine arts education, while fine arts education caused a decrease in social appearance anxiety when compared with students who received neither sport nor fine arts education. In terms of social appearance contribution, it is thought that art and music education have similar effects to those of sport. Giving sport education to students who are not receiving sport education or making them do sport and giving those interested in sport a chance to be interested in art can be a factor in decreasing social appearance anxiety.
The Study of Effects of Olympic-Style Weightlifting Trainings on the Thickness of the Quadriceps Femoris Tendon of Athletes
Authors: Erdağı Kenan , Tüfekçi Osman
Published: April 2019

Objectives: The study aims to investigate the thickness of the quadriceps femoris tendon in Olympic-style weightlifting athletes and sedentary individuals. Methods: The study included 25 women and 25 men Olympic-style weightlifting athletes aged 18-19 years as the study group and 25 women and 25 men sedentary individuals as the control group. In the study, the thickness of the quadriceps femoris tendon on both knees was measured by ultrasonographic imaging. Results: The mean thickness of the quadriceps femoris tendon was significantly larger in the athletes than in the sedentary individuals. No correlation was found between the age, height, training years of the athletes and the thickness of the quadriceps femoris tendon. Conclusion: It might be stated that Olympic-style weightlifting has a hypertrophic effect on the quadriceps femoris tendon of athletes.
Improved spike inference accuracy by estimating the peak amplitude of unitary [Ca2+] transients in weakly GCaMP6f‐expressing hippocampal pyramidal cells
Authors: Éltes Tímea , Szoboszlay Miklos , Kerti‐Szigeti Katalin , Nusser Zoltan
Published: April 2019

Key points

The amplitude of unitary, single action potential‐evoked [Ca2+] transients negatively correlates with GCaMP6f expression, but displays large variability among hippocampal pyramidal cells with similarly low expression levels.

The summation of fluorescence signals is frequency‐dependent, supralinear and also shows remarkable cell‐to‐cell variability.

The main source of spike inference error is variability in the peak amplitude, and not in the decay or supralinearity.

We developed two procedures to estimate the peak amplitudes of unitary [Ca2+] transients and show that spike inference performed with MLspike using these unitary amplitude estimates in weakly GCaMP6f‐expressing cells results in error rates of ∼5%.

Investigating neuronal activity using genetically encoded Ca2+ indicators in behaving animals is hampered by inaccuracies in spike inference from fluorescent tracers. Here we combine two‐photon [Ca2+] imaging with cell‐attached recordings, followed by post hoc determination of the expression level of GCaMP6f, to explore how it affects the amplitude, kinetics and temporal summation of somatic [Ca2+] transients in mouse hippocampal pyramidal cells (PCs). The amplitude of unitary [Ca2+] transients (evoked by a single action potential) negatively correlates with GCaMP6f expression, but displays large variability even among PCs with similarly low expression levels. The summation of fluorescence signals is frequency‐dependent, supralinear and also shows remarkable cell‐to‐cell variability. We performed experimental data‐based simulations and found that spike inference error rates using MLspike depend strongly on unitary peak amplitudes and GCaMP6f expression levels. We provide simple methods for estimating the unitary [Ca2+] transients in individual weakly GCaMP6f‐expressing PCs, with which we achieve spike inference error rates of ∼5%.
Modeling infrasonic propagation through a spherical atmospheric layer—Analysis of the stratospheric pair
Authors: Blom Philip
Published: April 2019

Methods are developed to calculate acoustic propagation paths through an atmospheric layer surrounding a spherical globe in order to more accurately model the propagation of infrasonic signals, which are often observed after propagating hundreds or thousands of kilometers. A generalized curvilinear coordinate system is used to define the ray tracing equations from the eikonal equation for a moving, inhomogeneous atmosphere, and the specific case of spherical coordinates is applied to obtain a system of coupled equations describing geometric propagation paths in an atmospheric layer surrounding a globe. Comparison with propagation predictions using a Cartesian geometry shows that even for relatively short infrasonic propagation distances of a few hundred kilometers, differences introduced by the change in geometry are significant. Characteristics of the stratospheric pair are considered, and it is found that differences in the upward and downward legs of the propagation paths corresponding to the fast and slow stratospheric arrivals are changed such that spherical coordinate geometry predicts a decrease in the relative arrival time between the two. Analysis of regional infrasonic signals produced by a series of surface explosions shows that predictions obtained using spherical geometry are more accurate in cases where the tropospheric and stratospheric waveguides are accurately characterized.
Sport Policy Institutionalization: Examining the Adoption of Concussion Legislation Across States
Authors: Lu Landy Di , Heinze Kathryn L.
Published: April 2019

Multilevel examinations of sport policy institutionalization are scarce in sport management scholarship. As sport policies diffuse across geographic boundaries, there is often variation in the timing of adoption. In this study, the authors used event history analysis to examine the effect of institutional factors, within and between states, on the speed of youth sport concussion legislation adoption. Our quantitative analyses show that a series of intrastate factors—state norms, disruptive events, and local advocacy—had a significant influence on the timing of state policy adoption, but interstate social networks did not. Supporting qualitative data provide additional insight about the relationship between disruptive events and local advocacy in the adoption of concussion legislation. This study contributes to a better understanding of institutional factors in the diffusion of sport policy across geographic boundaries and offers an approach for future research examining variation in sport policy or practice adoption.
Mechanism of Microbicidal Action of E-101 Solution, a Myeloperoxidase-Mediated Antimicrobial, and Its Oxidative Products
Authors: Denys Gerald A. , Devoe Neil C. , Gudis Polyxeni , May Meghan , Allen Robert C. , Stephens Jackson T.
Published: April 2019

E-101 solution is a first-in-class myeloperoxidase-mediated antimicrobial developed for topical application. It is composed of porcine myeloperoxidase (pMPO), glucose oxidase (GO), glucose, sodium chloride, and specific amino acids in an aqueous solution.
In Situ
Structures of Polar and Lateral Flagella Revealed by Cryo-Electron Tomography
Authors: Zhu Shiwei , Schniederberend Maren , Zhitnitsky Daniel , Jain Ruchi , Galán Jorge E. , Kazmierczak Barbara I. , Liu Jun
Published: April 2019

The bacterial flagellum has evolved as one of the most sophisticated self-assembled molecular machines, which confers locomotion and is often associated with virulence of bacterial pathogens. Variation in species-specific features of the flagellum, as well as in flagellar number and placement, results in structurally distinct flagella that appear to be adapted to the specific environments that bacteria encounter. Here, we used cutting-edge imaging techniques to determine high-resolution
in situ
structures of polar flagella in
Pseudomonas aeruginosa
and peritrichous flagella in
Salmonella enterica
serovar Typhimurium, demonstrating substantial variation between flagella in these organisms. Importantly, we observed novel flagellar subassemblies and provided additional insight into the structural basis of flagellar assembly and loss in both
P. aeruginosa
and
S
. Typhimurium.
Deep Mutational Scan of the Highly Conserved Influenza A Virus M1 Matrix Protein Reveals Substantial Intrinsic Mutational Tolerance
Authors: Hom Nancy , Gentles Lauren , Bloom Jesse D. , Lee Kelly K.
Published: April 2019

The M1 matrix protein is critical for many stages of the influenza virus infection cycle. Currently, we have an incomplete understanding of this highly conserved protein’s function and structure. Key regions of M1, particularly in the C terminus of the protein, remain poorly characterized. In this study, we used deep mutational scanning to determine the extent of M1’s tolerance to mutation. Surprisingly, nearly two-thirds of the M1 sequence exhibits a high tolerance for substitutions, contrary to the extremely low sequence diversity observed across naturally occurring M1 isolates. Sites with low mutational tolerance were also identified, suggesting that they likely play critical functional roles and are under selective pressure. These results reveal the intrinsic mutational tolerance throughout M1 and shape future inquiries probing the functions of this essential influenza A virus protein.
First Crystal Structure of a Nonstructural Hepatitis E Viral Protein Identifies a Putative Novel Zinc-Binding Protein
Authors: Proudfoot Andrew , Hyrina Anastasia , Holdorf Meghan , Frank Andreas O. , Bussiere Dirksen
Published: April 2019

Hepatitis E virus (HEV) is an emerging virus found predominately in developing countries; it causes an estimated 20 million infections, which result in approximately 57,000 deaths a year. Although it is known that the nonstructural proteins of HEV ORF1 are expressed as a single transcript, there is debate as to whether ORF1 functions as a single polyprotein or if it is processed into separate domains via a viral or endogenous cellular protease. Here we present the first structural and biophysical characterization of an HEV nonstructural protein using a construct that has partially overlapping boundaries with the predicted putative cysteine protease.
Coordination of Polyploid Chromosome Replication with Cell Size and Growth in a Cyanobacterium
Authors: Ohbayashi Ryudo , Nakamachi Ai , Hatakeyama Tetsuhiro S. , Watanabe Satoru , Kanesaki Yu , Chibazakura Taku , Yoshikawa Hirofumi , Miyagishima Shin-ya
Published: April 2019

Polyploidy has evolved many times across the kingdom of life. The relationship between cell growth and chromosome replication in bacteria has been studied extensively in monoploid model organisms such as
Escherichia
coli
but not in polyploid organisms. Our study of the polyploid cyanobacterium
Synechococcus elongatus
demonstrates that replicating chromosome number is restricted and regulated by DnaA to maintain a relatively stable gene copy number/cell volume ratio during cell growth. In addition, our results suggest that polyploidy confers resistance to UV, which damages DNA. This compensatory polyploidy is likely necessitated by photosynthesis, which requires sunlight and generates damaging reactive oxygen species, and may also explain how polyploid bacteria can adapt to extreme environments with high risk of DNA damage.
The Impact of Anthelmintic Treatment on Human Gut Microbiota Based on Cross-Sectional and Pre- and Postdeworming Comparisons in Western Kenya
Authors: Easton Alice V. , Quiñones Mariam , Vujkovic-Cvijin Ivan , Oliveira Rita G. , Kepha Stella , Odiere Maurice R. , Anderson Roy M. , Belkaid Yasmine , Nutman Thomas B.
Published: April 2019

The gut microbiome is an important factor in human health. It is affected by what we eat, what medicines we take, and what infections we acquire. In turn, it affects the way we absorb nutrients and whether we have excessive intestinal inflammation. Intestinal worms may have an important impact on the composition of the gut microbiome. Without a complete understanding of the impact of mass deworming programs on the microbiome, it is impossible to accurately calculate the cost-effectiveness of such public health interventions and to guard against any possible deleterious side effects. Our research examines this question in a “real-world” setting, using a longitudinal cohort, in which individuals with and without worm infections are treated with deworming medication and followed up at both three weeks and three months posttreatment. We quantify the impact of roundworms and hookworms on gut microbial composition, suggesting that the impact is small, but that treatment of hookworm infection results in significant changes. This work points to the need for follow-up studies to further examine the impact of hookworm on the gut microbiota and determine the health consequences of the observed changes.
Diversification of Colonization Factors in a Multidrug-Resistant Escherichia coli Lineage Evolving under Negative Frequency-Dependent Selection
Authors: McNally Alan , Kallonen Teemu , Connor Christopher , Abudahab Khalil , Aanensen David M. , Horner Carolyne , Peacock Sharon J. , Parkhill Julian , Croucher Nicholas J. , Corander Jukka
Published: April 2019

Infections with multidrug-resistant (MDR) strains of
Escherichia coli
are a significant global public health concern. To combat these pathogens, we need a deeper understanding of how they evolved from their background populations. By understanding the processes that underpin their emergence, we can design new strategies to limit evolution of new clones and combat existing clones. By combining population genomics with modelling approaches, we show that dominant MDR clones of
E. coli
are under the influence of negative frequency-dependent selection, preventing them from rising to fixation in a population. Furthermore, we show that this selection acts on genes involved in anaerobic metabolism, suggesting that this key trait, and the ability to colonize human intestinal tracts, is a key step in the evolution of MDR clones of
E. coli
.
Phycobilisomes Harbor FNR
L
in Cyanobacteria
Authors: Liu Haijun , Weisz Daniel A. , Zhang Mengru M. , Cheng Ming , Zhang Bojie , Zhang Hao , Gerstenecker Gary S. , Pakrasi Himadri B. , Gross Michael L. , Blankenship Robert E.
Published: April 2019

Cyanobacterial light-harvesting complex PBSs are essential for photochemistry in light reactions and for balancing energy flow to carbon fixation in the form of ATP and NADPH. We isolated a new type of PBS without an allophycocyanin core (i.e., CpcL-PBS). CpcL-PBS contains both a spectral red-shifted chromophore, enabling efficient energy transfer to chlorophyll molecules in the reaction centers, and an increased FNR
L
content with various rod lengths. Identification of a close association of FNR
L
with both CpcG-PBS and CpcL-PBS brings new insight to its regulatory role for fine-tuning light energy transfer and carbon fixation through both noncyclic and cyclic electron transport.
Effects of occupational exposure to respirable quartz dust on acute myocardial infarction
Authors: Gellissen Johannes , Pattloch Dagmar , Möhner Matthias
Published: April 2019

Objectives

The aim of this study is to investigate the effects of occupational exposure to respirable quartz (RQ) on first acute myocardial infarction (AMI). RQ causes pulmonary diseases like silicosis and has also been linked to cardiovascular diseases. Inflammation is hypothesised as the underlying pathway.

Methods

We performed a 1:3 matched case–control study nested in a cohort of male uranium miners. We included cases (identified from hospital records and validated according to WHO criteria) who had suffered their first AMI while still employed and <65 years of age. Controls were matched by date of birth and Wismut recruitment era. RQ exposure was derived from a job-exposure matrix. We performed a conditional logistic regression adjusted for smoking, metabolic syndrome and baseline erythrocyte sedimentation rate. Subgroups by date of birth and Wismut recruitment era were analysed to minimise the impact of pre-exposures.

Results

The study base comprised 292 matched sets. The cumulative exposure ranged from 0 to 38.9 mg/m3-years RQ. The adjusted OR of the highest RQ tertile (>14.62 mg/m3-years) was 1.27 (95% CI 0.82 to 1.98). However, for miners born after 1928 and hired in the earliest recruitment era (1946–1954), a significantly elevated risk was seen in the highest RQ tertile (OR=6.47 [95% CI 1.33 to 31.5]; 50 matched sets).

Conclusions

An impact of quartz dust on first AMI was observed only in a small subgroup that had virtually no pre-exposure to RQ. Further studies on the basis of complete occupational history are required to substantiate this finding.
Sexual network characteristics of men who have sex with men with syphilis and/or gonorrhoea/chlamydia in Lima, Peru: network patterns as roadmaps for STI prevention interventions
Authors: Blair Cherie , Passaro Ryan Colby , Segura Eddy R , Lake Jordan E , Perez-Brumer Amaya G , Sanchez Jorge , Lama Javier R , Clark Jesse L
Published: April 2019

Objective

While men who have sex with men (MSM) are disproportionately affected by Peru’s overlapping HIV and STI epidemics, there are few data on how partnership-level and network-level factors affect STI transmission in Peru. We explored partnership-level and network-level factors associated with gonorrhoea/chlamydia (Neisseria gonorrhoeaeand/orChlamydia trachomatis(NG/CT)) and/or syphilis infection among MSM in Peru.

Methods

We present the results of a cross-sectional secondary analysis of MSM (n=898) tested for syphilis and NG/CT infection as part of the screening process for two STI control trials in Lima, Peru. Participants completed questionnaires on demographics, sexual identity and role, characteristics of their three most recent sexual partners (partner sexual orientation, gender, role, partnership type, partner-specific sexual acts) and 30-day sexual network characteristics (number of sexual partners, partnership types, frequency of anal/vaginal intercourse). Participants were tested for syphilis and urethral, rectal and oropharyngeal NG/CT. Differences in network characteristics were analysed with χ2and Kruskal-Wallis tests.

Results

Approximately 38.9% of participants had a new STI diagnosis (syphilis (rapid plasma reagin ≥16): 10.6%; NG/CT: 22.9%; syphilis-NG/CT coinfection: 5.4%). Condomless anal intercourse (CAI) was not significantly associated with an STI diagnosis. Gay-identified participants with exclusively homosexual networks had a higher prevalence of STIs (47.4%) than gay-identified MSM with only heterosexual/bisexual partners (34.6%, p=0.04), despite reporting fewer sexual partners (any partners: 2, 1–4 vs 3, 2–6; p=0.001; casual partners: 1, 0–3 vs 2, 1–4; p=0.001) and more stable partnerships (1, 0–1 vs 0, 0–1; p=0.003) in the last month.

Conclusions

Network size and the number of casual sexual partners were associated with NG/CT infection among MSM in Peru. Despite reporting fewer sexual risk behaviours (smaller network size, more stable partnerships, less CAI), MSM with homosexual-only sexual networks had a higher prevalence of NG/CT and syphilis. These findings suggest network composition among MSM in Peru plays an important role in the risk for STI acquisition.
Gastroprotective activity ofLoranthus acaciaeflower extract in a rodent model of ethanol-induced ulcer
Authors: Abbas Manal A. , Kandil Yasser I. , Disi Ahmad M. , Jaffal Sahar M.
Published: April 2019

Loranthus acaciae (Loranthaceae) is a perennial green semi-parasitic plant used in ethnopharmacological medicine for healing wounds. The protective effect of L. acaciae on gastric ulcer induced by ethanol was investigated in a rat model. Ulcer index and total glutathione level were measured and histological and immunohistochemical studies for the expression of cyclooxygenase-2 were performed. Furthermore, chemical constituents of the flower extract were analyzed. Ulcer index was significantly lowered in L. acaciae-treated groups. Protection ratios were 75.9%, 98.9%, and 70.7% for 250 mg/kg and 500 mg/kg of L. acaciae and 40 mg/kg of esomeprazole, respectively. Histological examination revealed fewer hemorrhage in mucosa and less edema in submucosa of L. acaciae-treated groups compared with control. In the esomeprazole-treated group, there was mild disruption in the surface epithelium and mild hemorrhage. However, edema and leucocytes infiltration in the submucosa layer were present. Immunohistochemical staining of stomach sections for cyclooxygenase-2 (COX-2) was negative in the control group as well as in the L. acaciae-treated groups. Total glutathione level in mucosa layer of the stomach was higher in L. acaciae-treated groups compared with control. Liquid chromatography-mass spectrometric analysis revealed the presence of loranthin and rutin as the major constituents. It can be concluded that L. acaciae imparted a gastroprotective action against ethanol-induced ulcer in rats.

Novelty 500 mg/kg L. acaciae protected the stomach by 98.9% from ulcerogenic effect of ethanol. L. acaciae increased total glutathione level but not COX-2 expression in gastric mucosa. Loranthin and rutin were the major constituents in L. acaciae flower extract.
Markov chain modulated Poisson process to stimulate the number of blockages in sewer networks
Authors: Altarabsheh Ahmad , Ventresca Mario , Kandil Amr , Abraham Dulcy
Published: April 2019

Blockage failure is the most common type of operational failure in sewer networks that can cause loss of service and flooding, which can result in environmental pollution, health risks, property damage, and traffic disruption. There are currently very few blockage prediction models that are either deterministic in nature or depend only on static factors in predicting blockages. This study aims to overcome these drawbacks in the current blockage prediction models and proposes a methodology that aims to predict the expected number of blockages in sewer networks as a function of pipe conditions (dynamic variable) and pipe physical attributes (static variables) using a Markov chain modulated Poisson process modeling framework. The framework is applied to case study sewer network in the city of Sahab, Jordan, that contains information about the pipes’ physical attributes and their current condition. Bayesian analysis is then performed to evaluate the proposed framework.
Lyapunov Theory-Based Fusion Neural Networks for the Identification of Dynamic Nonlinear Systems
Authors: Plakias Spyridon , Boutalis Yiannis S.
Published: April 2019

This paper introduces a novel fusion neural architecture and the use of a novel Lyapunov theory-based algorithm, for the online approximation of the dynamics of nonlinear systems. The proposed neural system, in combination with the proposed update rule of the neural weights, achieves fast convergence of the identification process, ensuring at the same time stability of the error system in the sense of Lyapunov theory. The fusion neural system combines the features that are extracted from two-independent neural streams, a feedforward and a diagonal recurrent one, satisfying different design criteria of the identification task. Simulation results for five cases reveal the approximation strength of both proposed fusion neural architecture and proposed learning algorithm. Also, additional experiments demonstrate the effectiveness in cases of parameter variations and additive noise.
The necessary and sufficient condition for clustering of nodes based on the signs of connections in generalized signed networks
Authors: Wang Qi , Wang Yinhe , Gao Zilin , Zhang Lili , Wang Wenli
Published: April 2019

This paper investigates the clustering problem for the generalized signed networks. By rigorous derivations, a sufficient and necessary condition for clustering of the nodes in generalized signed networks is proposed in this paper. In order to obtain this condition, the concept of friends group is first introduced for the nodes based on their links’ sign. Then, the unprivileged network is also defined in this paper by employing the concepts of structural hole and broker. Compared with the existing clustering algorithms, the outstanding advantage in this paper is that only the positive or negative (especially, or zero) sign of the links is required regardless of their density or sparsity. We have proved mathematically that a generalized signed network is classifiable if and only if it is an unprivileged network. Finally, two examples associated with numerical simulations are proposed to generate the unprivileged networks.
Ground state of spin-2 dipolar rotating Bose–Einstein condensates
Authors: Zhao Qiang
Published: April 2019

We study the ground state of spin-2 dipolar rotating Bose–Einstein condensates in a harmonic potential. As the strength of dipolar interaction enhances, our results show that the vortex number becomes smaller and smaller at a fixed component. In addition, the vortex stripe occurs and its number increases. The components m[Formula: see text]1 or ±2 display the same density and the total density shows layered distribution. Increasing the rotational frequency to a higher value, the vortex number and vortex row number increase. We also plot the dependence of angular momentum Lz as a function of dipole strength c[Formula: see text], showing that Lz decreases with increasing c[Formula: see text].
Interfacial properties of aramid/basalt fiber reinforced hybrid composites by addition of Halloysite nanotube
Authors: Lee Jin-Woo , Yu Tianyu , Park Soo-Jeong , Kim Yun-Hae
Published: April 2019

We investigated the effect of Halloysite nanotube (HNT) addition on the interfacial and bending properties of hybrid composites. Test specimens were prepared using a vacuum bag method, which is manufactured by using an autoclave device. Ultrasound device was used to uniformly disperse HNT nanoparticles into the epoxy. Amount of the nanoparticles was determined by the weight of the epoxy resin. The Fracture toughness, ILSS and bending strength of Aramid/Basalt fiber hybrid composite specimens were decreased by more than certain amount of HNT. This phenomenon is presumably due to aggregation of HNT.
Study on optimization of laser cladding using Stellite 6 powder for exhaust valve face of marine engine
Authors: Song Moo-Keun , Park Su-Han , Lee Su-Jin , Kim Jong-Do
Published: April 2019

In this study, experiments with various parameters were performed to apply laser cladding to the exhaust valve face of a marine engine and optimum conditions were derived. The used specimen was an actual exhaust valve, and the heat source was a high-power diode laser. Cladding was applied to the exhaust valve face using the optimum conditions, and a sound clad layer without internal defects, such as pores and cracks, was formed. The average hardness of the clad layer formed under the optimum conditions was higher than 529 Hv. Component analysis showed a very low dilution rate inside the clad layer.