bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and Regulatory Changes in PBP4 Trigger Decreased β-Lactam Susceptibility in Enterococcus faecalis
Authors: Rice Louis B. , Desbonnet Charlene , Tait-Kamradt Amelia , Garcia-Solache Monica , Lonks John , Moon Thomas M. , D’Andréa Éverton D. , Page Rebecca , Peti Wolfgang
Published: April 2018

Enterococcus faecalis
strains resistant to penicillin and ampicillin are rare and have been associated with increases in quantities of low-affinity penicillin-binding protein 4 (PBP4) or with amino acid substitutions in PBP4. We report an
E. faecalis
strain (LS4828) isolated from a prosthetic knee joint that was subjected to long-term exposure to aminopenicillins. Subsequent cultures yielded
E. faecalis
with MICs of penicillins and carbapenems higher than those for wild-type strain
E. faecalis
JH2-2. Sequence analysis of the
pbp4
gene of LS4828 compared to that of JH2-2 revealed two point mutations with amino acid substitutions (V223I, A617T) and deletion of an adenine from the region upstream of the predicted
pbp4
−35 promoter sequence (UP region). Purified PBP4 from LS4828 exhibited less affinity for Bocillin FL than did PBP4 from JH2-2, which was recapitulated by purified PBP4 containing only the A617T mutation. Differential scanning fluorimetry studies showed that the LS4828 and A617T variants are destabilized compared to wild-type PBP4. Further, reverse transcription-PCR indicated increased transcription of
pbp4
in LS4828 and Western blot analysis with polyclonal PBP4 antibody revealed greater quantities of PBP4 in LS4828 than in JH2-2 lysates and membrane preparations. Placing the promoter regions from LS4828 or JH2-2 upstream of a green fluorescent protein reporter gene confirmed that the adenine deletion was associated with increased transcription. Together, these data suggest that the reduced susceptibility to β-lactam antibiotics observed in
E. faecalis
LS4828 results from a combination of both increased expression and remodeling of the active site, resulting in reduced affinity for penicillins and carbapenems.

IMPORTANCE
Enterococcus faecalis
is an important cause of community-acquired and nosocomial infections and creates therapeutic dilemmas because of its frequent resistance to several classes of antibiotics. We report an
E. faecalis
strain with decreased ampicillin and imipenem susceptibility isolated after prolonged courses of aminopenicillin therapy for a prosthetic joint infection. Its reduced susceptibility is attributable to a combination of increased quantities of low-affinity PBP4 and an amino acid substitution in proximity to the active site that destabilizes the protein. Our findings provide a cautionary tale for clinicians who elect to “suppress” infections in prosthetic joints and offer novel insights into the interaction of β-lactam antibiotics with low-affinity PBP4. These insights will help inform future efforts to develop therapeutics capable of inhibiting clinical enterococcal strains.
CRISPR/Cas9-Mediated Gene Disruption Reveals the Importance of Zinc Metabolism for Fitness of the Dimorphic Fungal Pathogen Blastomyces dermatitidis
Authors: Kujoth Gregory C. , Sullivan Thomas D. , Merkhofer Richard , Lee Taek-Jin , Wang Huafeng , Brandhorst Tristan , Wüthrich Marcel , Klein Bruce S.
Published: April 2018

Blastomyces dermatitidis
is a human fungal pathogen of the lung that can lead to disseminated disease in healthy and immunocompromised individuals. Genetic analysis of this fungus is hampered by the relative inefficiency of traditional recombination-based gene-targeting approaches. Here, we demonstrate the feasibility of applying CRISPR/Cas9-mediated gene editing to
Blastomyces
, including to simultaneously target multiple genes. We created targeting plasmid vectors expressing Cas9 and either one or two single guide RNAs and introduced these plasmids into
Blastomyces
via
Agrobacterium
gene transfer. We succeeded in disrupting several fungal genes, including
PRA1
and
ZRT1
, which are involved in scavenging and uptake of zinc from the extracellular environment. Single-gene-targeting efficiencies varied by locus (median, 60% across four loci) but were approximately 100-fold greater than traditional methods of
Blastomyces
gene disruption. Simultaneous dual-gene targeting proceeded with efficiencies similar to those of single-gene-targeting frequencies for the respective targets. CRISPR/Cas9 disruption of
PRA1
or
ZRT1
had a variable impact on growth under zinc-limiting conditions, showing reduced growth at early time points in low-passage-number cultures and growth similar to wild-type levels by later passage. Individual impairment of
PRA1
or
ZRT1
resulted in a reduction of the fungal burden in a mouse model of
Blastomyces
infection by a factor of ~1 log (range, up to 3 logs), and combined disruption of both genes had no additional impact on the fungal burden. These results underscore the utility of CRISPR/Cas9 for efficient gene disruption in dimorphic fungi and reveal a role for zinc metabolism in
Blastomyces
fitness
in vivo
.

IMPORTANCE
Blastomyces
is a human fungal pathogen that can cause serious, even fatal, lung infections. Genetic analysis of this fungus is possible but inefficient. We applied a recently developed gene editing technology, CRISPR/Cas9, to dramatically improve the efficiency with which gene disruptions are introduced into
Blastomyces
. We used this system to disrupt genes involved in zinc uptake and found that this reduced the fitness of the fungus upon infection.
Genomic Analysis of a Pan-Resistant Isolate of
Klebsiella pneumoniae
, United States 2016
Authors: de Man Tom J. B. , Lutgring Joseph D. , Lonsway David R. , Anderson Karen F. , Kiehlbauch Julia A. , Chen Lei , Walters Maroya Spalding , Sjölund-Karlsson Maria , Rasheed J. Kamile , Kallen Alexander , Halpin Alison Laufer
Published: April 2018

Antimicrobial resistance is a threat to public health globally and leads to an estimated 23,000 deaths annually in the United States alone. Here, we report the genomic characterization of an unusual
Klebsiella pneumoniae
, nonsusceptible to all 26 antibiotics tested, that was isolated from a U.S. patient. The isolate harbored four known beta-lactamase genes, including plasmid-mediated
bla
NDM-1
and
bla
CMY-6
, as well as chromosomal
bla
CTX-M-15
and
bla
SHV-28
, which accounted for resistance to all beta-lactams tested. In addition, sequence analysis identified mechanisms that could explain all other reported nonsusceptibility results, including nonsusceptibility to colistin, tigecycline, and chloramphenicol. Two plasmids, IncA/C2 and IncFIB, were closely related to mobile elements described previously and isolated from Gram-negative bacteria from China, Nepal, India, the United States, and Kenya, suggesting possible origins of the isolate and plasmids. This is one of the first
K. pneumoniae
isolates in the United States to have been reported to the Centers for Disease Control and Prevention (CDC) as nonsusceptible to all drugs tested, including all beta-lactams, colistin, and tigecycline.

IMPORTANCE
Antimicrobial resistance is a major public health threat worldwide. Bacteria that are nonsusceptible or resistant to all antimicrobials available are of major concern to patients and the public because of lack of treatment options and potential for spread. A
Klebsiella pneumoniae
strain that was nonsusceptible to all tested antibiotics was isolated from a U.S. patient. Mechanisms that could explain all observed phenotypic antimicrobial resistance phenotypes, including resistance to colistin and beta-lactams, were identified through whole-genome sequencing. The large variety of resistance determinants identified demonstrates the usefulness of whole-genome sequencing for detecting these genes in an outbreak response. Sequencing of isolates with rare and unusual phenotypes can provide information on how these extremely resistant isolates develop, including whether resistance is acquired on mobile elements or accumulated through chromosomal mutations. Moreover, this provides further insight into not only detecting these highly resistant organisms but also preventing their spread.
Coexistence of Multiple Endemic and Pandemic Lineages of the Rice Blast Pathogen
Authors: Gladieux Pierre , Ravel Sébastien , Rieux Adrien , Cros-Arteil Sandrine , Adreit Henri , Milazzo Joëlle , Thierry Maud , Fournier Elisabeth , Terauchi Ryohei , Tharreau Didier
Published: April 2018

The rice blast fungus
Magnaporthe oryzae
(syn.,
Pyricularia oryzae
) is both a threat to global food security and a model for plant pathology. Molecular pathologists need an accurate understanding of the origins and line of descent of
M. oryzae
populations in order to identify the genetic and functional bases of pathogen adaptation and to guide the development of more effective control strategies. We used a whole-genome sequence analysis of samples from different times and places to infer details about the genetic makeup of
M. oryzae
from a global collection of isolates. Analyses of population structure identified six lineages within
M. oryzae
, including two pandemic on japonica and indica rice, respectively, and four lineages with more restricted distributions. Tip-dating calibration indicated that
M. oryzae
lineages separated about a millennium ago, long after the initial domestication of rice. The major lineage endemic to continental Southeast Asia displayed signatures of sexual recombination and evidence of DNA acquisition from multiple lineages. Tests for weak natural selection revealed that the pandemic spread of clonal lineages entailed an evolutionary “cost,” in terms of the accumulation of deleterious mutations. Our findings reveal the coexistence of multiple endemic and pandemic lineages with contrasting population and genetic characteristics within a widely distributed pathogen.

IMPORTANCE
The rice blast fungus
Magnaporthe oryzae
(syn.,
Pyricularia oryzae
) is a textbook example of a rapidly adapting pathogen, and it is responsible for one of the most damaging diseases of rice. Improvements in our understanding of
Magnaporthe oryzae
’s diversity and evolution are required to guide the development of more effective control strategies. We used genome sequencing data for samples from around the world to infer the evolutionary history of
M. oryzae
. We found that
M. oryzae
diversified about 1,000 years ago, separating into six main lineages: two pandemic on japonica and indica rice, respectively, and four with more restricted distributions. We also found that a lineage endemic to continental Southeast Asia displayed signatures of sexual recombination and the acquisition of genetic material from multiple lineages. This work provides a population-level genomic framework for defining molecular markers for the control of rice blast and investigations of the molecular basis of differences in pathogenicity between
M. oryzae
lineages.
NAction! How Can Neuraminidase-Based Immunity Contribute to Better Influenza Virus Vaccines?
Authors: Krammer Florian , Fouchier Ron A. M. , Eichelberger Maryna C. , Webby Richard J. , Shaw-Saliba Kathryn , Wan Hongquan , Wilson Patrick C. , Compans Richard W. , Skountzou Ioanna , Monto Arnold S.
Published: April 2018

Neuraminidase is one of the two surface glycoproteins of influenza A and B viruses. It has enzymatic activity that cleaves terminal sialic acid from glycans, and that activity is essential at several points in the virus life cycle. While neuraminidase is a major target for influenza antivirals, it is largely ignored in vaccine development. Current inactivated influenza virus vaccines might contain neuraminidase, but the antigen quantity and quality are varied and not standardized. While there are data that show a protective role of anti-neuraminidase immunity, many questions remain unanswered. These questions, among others, concern the targeted epitopes or antigenic sites, the potential for antigenic drift, and, connected to that, the breadth of protection, differences in induction of immune responses by vaccination versus infection, mechanisms of protection, the role of mucosal antineuraminidase antibodies, stability, and the immunogenicity of neuraminidase in vaccine formulations. Reagents for analysis of neuraminidase-based immunity are scarce, and assays are not widely used for clinical studies evaluating vaccines. However, efforts to better understand neuraminidase-based immunity have been made recently. A neuraminidase focus group, NAction!, was formed at a Centers of Excellence for Influenza Research and Surveillance meeting at the National Institutes of Health in Bethesda, MD, to promote research that helps to understand neuraminidase-based immunity and how it can contribute to the design of better and broadly protective influenza virus vaccines. Here, we review open questions and knowledge gaps that have been identified by this group and discuss how the gaps can be addressed, with the ultimate goal of designing better influenza virus vaccines.
Trust, fear, stigma and disruptions: community perceptions and experiences during periods of low but ongoing transmission of Ebola virus disease in Sierra Leone, 2015
Authors: Nuriddin Azizeh , Jalloh Mohamed F , Meyer Erika , Bunnell Rebecca , Bio Franklin A , Jalloh Mohammad B , Sengeh Paul , Hageman Kathy M , Carroll Dianna D , Conteh Lansana , Morgan Oliver
Published: April 2018

Social mobilisation and risk communication were essential to the 2014–2015 West African Ebola response. By March 2015, >8500 Ebola cases and 3370 Ebola deaths were confirmed in Sierra Leone. Response efforts were focused on ‘getting to zero and staying at zero’. A critical component of this plan was to deepen and sustain community engagement. Several national quantitative studies conducted during this time revealed Ebola knowledge, personal prevention practices and traditional burial procedures improved as the outbreak waned, but healthcare system challenges were also noted. Few qualitative studies have examined these combined factors, along with survivor stigma during periods of ongoing transmission. To obtain an in-depth understanding of people’s perceptions, attitudes and behaviours associated with Ebola transmission risks, 27 focus groups were conducted between April and May 2015 with adult Sierra Leonean community members on: trust in the healthcare system, interactions with Ebola survivors, impact of Ebola on lives and livelihood, and barriers and facilitators to ending the outbreak. Participants perceived that as healthcare practices and facilities improved, so did community trust. Resource management remained a noted concern. Perceptions of survivors ranged from sympathy and empathy to fear and stigmatisation. Barriers included persistent denial of ongoing Ebola transmission, secret burials and movement across porous borders. Facilitators included personal protective actions, consistent messaging and the inclusion of women and survivors in the response. Understanding community experiences during the devastating Ebola epidemic provides practical lessons for engaging similar communities in risk communication and social mobilisation during future outbreaks and public health emergencies.
Chronic kidney disease care models in low- and middle-income countries: a systematic review
Authors: Stanifer John W , Von Isenburg Megan , Chertow Glenn M , Anand Shuchi
Published: April 2018

Introduction

The number of persons with chronic kidney disease (CKD) living in low- and middle-income countries (LMIC) is increasing rapidly; yet systems built to care for them have received little attention. In order to inform the development of scalable CKD care models, we conducted a systematic review to characterise existing CKD care models in LMICs.

Methods

We searched PubMed, Embase and WHO Global Health Library databases for published reports of CKD care models from LMICs between January 2000 and 31 October 2017. We used a combination of database-specific medical subject headings and keywords for care models, CKD and LMICs as defined by the World Bank.

Results

Of 3367 retrieved articles, we reviewed the full text of 104 and identified 17 articles describing 16 programmes from 10 countries for inclusion. National efforts (n=4) focused on the prevention of end-stage renal disease through enhanced screening, public awareness campaigns and education for primary care providers. Of the 12 clinical care models, nine focused on persons with CKD and the remaining on persons at risk for CKD; a majority in the first category implemented a multidisciplinary clinic with allied health professionals or primary care providers (rather than nephrologists) in lead roles. Four clinical care models used a randomised control design allowing for assessment of programme effectiveness, but only one was assessed as having low risk for bias; all four showed significant attenuation of kidney function decline in the intervention arms.

Conclusions

Overall, very few rigorous CKD care models have been reported from LMICs. While preliminary data indicate that national efforts or clinical CKD care models bolstering primary care are successful in slowing kidney function decline, limited data on regional causes of CKD to inform national campaigns, and on effectiveness and affordability of local programmes represent important challenges to scalability.
Neonatal Seizure Detection Using Deep Convolutional Neural Networks
Authors: Ansari Amir H. , Cherian Perumpillichira J. , Caicedo Alexander , Naulaers Gunnar , De Vos Maarten , Van Huffel Sabine
Published: April 2018

Identifying a core set of features is one of the most important steps in the development of an automated seizure detector. In most of the published studies describing features and seizure classifiers, the features were hand-engineered, which may not be optimal. The main goal of the present paper is using deep convolutional neural networks (CNNs) and random forest to automatically optimize feature selection and classification. The input of the proposed classifier is raw multi-channel EEG and the output is the class label: seizure/nonseizure. By training this network, the required features are optimized, while fitting a nonlinear classifier on the features. After training the network with EEG recordings of 26 neonates, five end layers performing the classification were replaced with a random forest classifier in order to improve the performance. This resulted in a false alarm rate of 0.9 per hour and seizure detection rate of 77% using a test set of EEG recordings of 22 neonates that also included dubious seizures. The newly proposed CNN classifier outperformed three data-driven feature-based approaches and performed similar to a previously developed heuristic method.
Simplified and Yet Turing Universal Spiking Neural P Systems with Communication on Request
Authors: Wu Tingfang , Bîlbîe Florin-Daniel , Păun Andrei , Pan Linqiang , Neri Ferrante
Published: April 2018

Spiking neural P systems are a class of third generation neural networks belonging to the framework of membrane computing. Spiking neural P systems with communication on request (SNQ P systems) are a type of spiking neural P system where the spikes are requested from neighboring neurons. SNQ P systems have previously been proved to be universal (computationally equivalent to Turing machines) when two types of spikes are considered. This paper studies a simplified version of SNQ P systems, i.e. SNQ P systems with one type of spike. It is proved that one type of spike is enough to guarantee the Turing universality of SNQ P systems. Theoretical results are shown in the cases of the SNQ P system used in both generating and accepting modes. Furthermore, the influence of the number of unbounded neurons (the number of spikes in a neuron is not bounded) on the computation power of SNQ P systems with one type of spike is investigated. It is found that SNQ P systems functioning as number generating devices with one type of spike and four unbounded neurons are Turing universal.
Integrating EEG and MEG Signals to Improve Motor Imagery Classification in Brain–Computer Interface
Authors: Corsi Marie-Constance , Chavez Mario , Schwartz Denis , Hugueville Laurent , Khambhati Ankit N. , Bassett Danielle S. , De Vico Fallani Fabrizio
Published: April 2018

We adopted a fusion approach that combines features from simultaneously recorded electroencephalogram (EEG) and magnetoencephalogram (MEG) signals to improve classification performances in motor imagery-based brain–computer interfaces (BCIs). We applied our approach to a group of 15 healthy subjects and found a significant classification performance enhancement as compared to standard single-modality approaches in the alpha and beta bands. Taken together, our findings demonstrate the advantage of considering multimodal approaches as complementary tools for improving the impact of noninvasive BCIs.
Radioactive contamination of scintillators
Authors: Danevich F. A. , Tretyak V. I.
Published: April 2018

Low counting experiments (search for double [Formula: see text] decay and dark matter particles, measurements of neutrino fluxes from different sources, search for hypothetical nuclear and subnuclear processes, low background [Formula: see text], [Formula: see text], [Formula: see text] spectrometry) require extremely low background of a detector. Scintillators are widely used to search for rare events both as conventional scintillation detectors and as cryogenic scintillating bolometers. Radioactive contamination of a scintillation material plays a key role to reach low level of background. Origin and nature of radioactive contamination of scintillators, experimental methods and results are reviewed. A programme to develop radiopure crystal scintillators for low counting experiments is discussed briefly.
Spatial correlation analysis of urban traffic state under a perspective of community detection
Authors: Yang Yanfang , Cao Jiandong , Qin Yong , Jia Limin , Dong Honghui , Zhang Aomuhan
Published: April 2018

Understanding the spatial correlation of urban traffic state is essential for identifying the evolution patterns of urban traffic state. However, the distribution of traffic state always has characteristics of large spatial span and heterogeneity. This paper adapts the concept of community detection to the correlation network of urban traffic state and proposes a new perspective to identify the spatial correlation patterns of traffic state. In the proposed urban traffic network, the nodes represent road segments, and an edge between a pair of nodes is added depending on the result of significance test for the corresponding correlation of traffic state. Further, the process of community detection in the urban traffic network (named GWPA-K-means) is applied to analyze the spatial dependency of traffic state. The proposed method extends the traditional K-means algorithm in two steps: (i) redefines the initial cluster centers by two properties of nodes (the GWPA value and the minimum shortest path length); (ii) utilizes the weight signal propagation process to transfer the topological information of the urban traffic network into a node similarity matrix. Finally, numerical experiments are conducted on a simple network and a real urban road network in Beijing. The results show that GWPA-K-means algorithm is valid in spatial correlation analysis of traffic state. The network science and community structure analysis perform well in describing the spatial heterogeneity of traffic state on a large spatial scale.
The adsorption properties of CHx species on metal modified graphene
Authors: Tang Yanan , Shen Zigang , Chen Weiguang , Zhu Dalei , Chai Huadou , Zhao Mingyu
Published: April 2018

The adsorption geometries of CH[Formula: see text] species (x = 0, 1, 2, 3 and 4) on the metal embedded graphene (M–graphene) substrates and the change in electronic structure and magnetic property of systems are analyzed using the first-principles calculations. The calculated results show that the doped metal atoms can provide transferred electrons to neighboring carbon atoms at defective site and thus exhibit positive charges, as well as turning the adsorption sensing of M–graphene for detecting CH[Formula: see text] species. Compared with the adsorbed CH3, the adsorption of C, CH and CH2 species exhibit more stability ([Formula: see text]3.0 eV) on M–graphene. Besides, more stable C atom on M–graphene can effectively turn the magnetic property of systems as compared with other species. This result provides a useful reference for fabricating the functional metal–graphene complex as gas sensors and catalytic materials.
An efficient routing strategy for traffic dynamics on two-layer complex networks
Authors: Ma Jinlong , Wang Huiling , Zhang Zhuxi , Zhang Yi , Duan Congwen , Qi Zhaohui , Liu Yu
Published: April 2018

In order to alleviate traffic congestion on multilayer networks, designing an efficient routing strategy is one of the most important ways. In this paper, a novel routing strategy is proposed to reduce traffic congestion on two-layer networks. In the proposed strategy, the optimal paths in the physical layer are chosen by comprehensively considering the roles of nodes’ degrees of the two layers. Both numerical and analytical results indicate that our routing strategy can reasonably redistribute the traffic load of the physical layer, and thus the traffic capacity of two-layer complex networks are significantly enhanced compared with the shortest path routing (SPR) and the global awareness routing (GAR) strategies. This study may shed some light on the optimization of networked traffic dynamics.
Fabrication of absorption gratings with X-ray lithography for X-ray phase contrast imaging
Authors: Wang Bo , Wang Yu-Ting , Yi Fu-Ting , Zhang Tian-Chong , Liu Jing , Zhou Yue
Published: April 2018

Grating-based X-ray phase contrast imaging is promising especially in the medical area. Two or three gratings are involved in grating-based X-ray phase contrast imaging in which the absorption grating of high-aspect-ratio is the most important device and the fabrication process is a great challenge. The material with large atomic number Z is used to fabricate the absorption grating for excellent absorption of X-ray, and Au is usually used. The fabrication process, which involves X-ray lithography, development and gold electroplating, is described in this paper. The absorption gratings with 4 [Formula: see text]m period and about 100 [Formula: see text]m height are fabricated and the high-aspect-ratio is 50.
Weight-Equitable Subdivision of Red and Blue Points in the Plane
Authors: Buot Jude , Kano Mikio
Published: April 2018

Let [Formula: see text] and [Formula: see text] be two disjoint sets of red points and blue points, respectively, in the plane in general position. Assign a weight [Formula: see text] to each red point and a weight [Formula: see text] to each blue point, where [Formula: see text] and [Formula: see text] are positive integers. Define the weight of a region in the plane as the sum of the weights of red and blue points in it. We give necessary and sufficient conditions for the existence of a line that bisects the weight of the plane whenever the total weight [Formula: see text] is [Formula: see text], for some integer [Formula: see text]. Moreover, we look closely into the special case where [Formula: see text] and [Formula: see text] since this case is important to generate a weight-equitable subdivision of the plane. Among other results, we show that for any configuration of [Formula: see text] with total weight [Formula: see text], for some integer [Formula: see text] and odd integer [Formula: see text], the plane can be subdivided into [Formula: see text] convex regions of weight [Formula: see text] if and only if [Formula: see text]. Using the proofs of the main result, we also give a polynomial time algorithm in finding a weight-equitable subdivision in the plane.
DYNAMIC MEAN–VARIANCE OPTIMIZATION PROBLEMS WITH DETERMINISTIC INFORMATION
Authors: SCHWEIZER MARTIN , ZIVOI DANIJEL , ŠIKIĆ MARIO
Published: April 2018

We solve the problems of mean–variance hedging (MVH) and mean–variance portfolio selection (MVPS) under restricted information. We work in a setting where the underlying price process [Formula: see text] is a semimartingale, but not adapted to the filtration [Formula: see text] which models the information available for constructing trading strategies. We choose as [Formula: see text] the zero-information filtration and assume that [Formula: see text] is a time-dependent affine transformation of a square-integrable martingale. This class of processes includes in particular arithmetic and exponential Lévy models with suitable integrability. We give explicit solutions to the MVH and MVPS problems in this setting, and we show for the Lévy case how they can be expressed in terms of the Lévy triplet. Explicit formulas are obtained for hedging European call options in the Bachelier and Black–Scholes models.
DYNAMIC ANALYSIS OF THREE DIFFERENT HIGH BAR DISMOUNTS IN THE SIMMECHANICS ENVIRONMENT
Authors: SERBEST KASIM , BERISHA MILAIM , CILLI MURAT
Published: April 2018

This study compares certain kinematic and kinetic parameters in giant circles performed before twisting, double stretched and double tucked dismounts using the dynamic model in the SimMechanics environment. The joint moments calculated using the designed model were investigated for the three different dismounts. The study included a 13-year-old voluntary national gymnast with seven years of training history. Markers were placed on the wrist, elbow, shoulder, hip, knee and ankle joints of the gymnast. The gymnast was asked to perform twisting, double stretched and double tucked dismounts. MATLAB and SimMechanics were used to calculate joint moments. The moves were simulated and the joint moments during the moves were calculated using the SimMechanics toolbox. The study observed that the highest joint moment was in the wrist joint in all three dismounts, in line with the findings of previous studies. However, unlike other studies, higher joint moments were calculated in the accelerated giant circle performed together with thrusts, compared with the regular giant circle. While there were similar maximum moment values in twisting dismounts and double tucked dismounts, an almost three times higher moment was observed in double stretched dismounts. In terms of joint moments, stretched dismount is obviously the most difficult move, which is consistent with the difficulty levels. A recorded performance of the mechanical model created in the SimMechanics environment was investigated in terms of the twist angle and moments generated on the bar, and found to be sufficient and useful. However, there are certain restrictions regarding the methods employed in this study. We concluded that the mechanical model will allow for the performance of kinematic and kinetic analyses of different gymnasts and types of moves thanks to its flexible structure.
STUDY ON VIBRATION CHARACTERISTICS AND TRANSMISSION PERFORMANCE OF ROUND WINDOW MEMBRANE UNDER INVERSE EXCITATION
Authors: YAO WENJUAN , TANG DUTIN , CHEN YIQIANG , LI BINGTAI
Published: April 2018

According to the vibration characteristics of the round window membrane, a mechanical model that contains round window membrane and the soft tissue is established. The Euler equation of the whole of round window membrane and the soft tissue and the complementary boundary conditions are derived by the variational principle. Combined with the Bessel function, the analytical solution of the total displacement of round window membrane and the soft tissue is obtained by using Mathematica. The results are in good agreement with experimental data, which confirms the validity of the analytical solution of the model. At the same time, the effect of different thicknesses and different elastic modulus of soft tissue on the total displacement of round window membrane and soft tissue is studied by analytical method. The results show that with the thickening of the soft tissue, the total displacement of round window membrane and the soft tissue decreased gradually. However, with the decrease of elastic modulus of the soft tissue, the total displacement of round window membrane and the soft tissue increased gradually. Furthermore, the relationship between thickness and elastic modulus of the soft tissue and the corresponding range selection is achieved, which can evaluate the transmission performance of round window membrane efficiently and provide theoretical basis for the reverse excitation of artificial prosthesis.
Quantum color image watermarking based on Arnold transformation and LSB steganography
Authors: Zhou Ri-Gui , Hu Wenwen , Fan Ping , Luo Gaofeng
Published: April 2018

In this paper, a quantum color image watermarking scheme is proposed through twice-scrambling of Arnold transformations and steganography of least significant bit (LSB). Both carrier image and watermark images are represented by the novel quantum representation of color digital images model (NCQI). The image sizes for carrier and watermark are assumed to be [Formula: see text] and [Formula: see text], respectively. At first, the watermark is scrambled into a disordered form through image preprocessing technique of exchanging the image pixel position and altering the color information based on Arnold transforms, simultaneously. Then, the scrambled watermark with [Formula: see text] image size and 24-qubit grayscale is further expanded to an image with size [Formula: see text] and 6-qubit grayscale using the nearest-neighbor interpolation method. Finally, the scrambled and expanded watermark is embedded into the carrier by steganography of LSB scheme, and a key image with [Formula: see text] size and 3-qubit information is generated at the meantime, which only can use the key image to retrieve the original watermark. The extraction of watermark is the reverse process of embedding, which is achieved by applying a sequence of operations in the reverse order. Simulation-based experimental results involving different carrier and watermark images (i.e. conventional or non-quantum) are simulated based on the classical computer’s MATLAB 2014b software, which illustrates that the present method has a good performance in terms of three items: visual quality, robustness and steganography capacity.
A Moving Kriging Interpolation Meshfree Method Based on Naturally Stabilized Nodal Integration Scheme for Plate Analysis
Authors: Thai Chien H. , Nguyen-Xuan H.
Published: April 2018

A moving Kriging interpolation (MKI) meshfree method based on naturally stabilized nodal integration (NSNI) scheme is presented to study static, free vibration and buckling behaviors of isotropic Reissner–Mindlin plates. Gradient strains are directly computed at nodes similar to the direct nodal integration (DNI). Outstanding features of the current approach are to alleviate instability solutions in the DNI and to decrease computational cost significantly when compared with the traditional high-order Gauss quadrature scheme. The NSNI is a naturally implicit gradient expansion and does not employ a divergence theorem for strain fields as addressed in the stabilized conforming nodal integration method. The present formulation is derived from the Galerkin weak form and avoids a naturally shear-locking phenomenon without using any other techniques. Thanks to satisfied Kronecker delta function property of MKI shape function, essential boundary conditions (BCs) are easily and directly enforced similar to the finite element method. A variety of numerical examples with various geometries, stiffness ratios and BCs are studied to verify the effectiveness of the present approach.
3D Adaptive Combined DE/FE Algorithm for Analyzing Impact Fracture of Laminated Glass
Authors: Xu Wei , Zang Mengyan , Sakamoto Jiro , Zhang Shupei
Published: April 2018

Laminated glass has been wildly employed in automobile windshields, modern buildings, etc. thanks to its security and durability performance. A novel 3D adaptive combined DE/FE algorithm is proposed to research its impact fracture mechanical properties if the fracture region is small relative to a specimen while the cracks are propagating at a random position. The proposed method can automatically convert the distorted finite elements into the spherical discrete elements during simulating the impact fracture of laminated glass. In this method a system is completely discretized into the finite elements at the initial moment without any discrete element existing until part of the finite elements becoming severely deformed. Subsequently each finite element, whose maximum tensile stress exceeds a user-specified conversion criterion, is converted into eight spherical discrete elements. At the same time the system is fragmented into two subdomains, the finite element (FE) and the discrete element (DE) subdomains. An extrinsic cohesive fracture model is adaptively adopted only in the DE subregion to capture the crack propagation when the normal stress between the DEs equals or exceeds the cohesive strength. The impact fracture of a glass beam is simulated by the adaptive algorithm and the discrete element method, respectively. Beside of the micro-cracks and cohesive zone, almost the same crack patterns are captured by both the numerical methods. Fortunately, the efficiency of the proposed method is much higher (10 times in this case) than that of the pure DEM. A satisfactory agreement of the simulation results certified the feasibility and effectiveness of such an adaptive algorithm. Finally, the impact fracture simulation is performed by the adaptive algorithm on a laminated glass beam which has the same size as the experimental specimens. Besides of the differences on the cracks occurrence and propagation angle, a similar agreement of the fracture patterns is observed as the experimental results. The common conclusions on the role of PVB interlayer can be obviously obtained by analyzing the simulation results, the same by analyzing the experimental ones. The proposed method is hopeful to be employed to analyze the impact fracture of an automobile windshield subjects to the head impact for the protection of pedestrians safety, the traffic accident reconstruction and the structural optimization of windshield.
Stimuli-triggered reversible switching mechanism between H- and J-type supramolecular assemblies of cationic porphyrins adsorbed on tungsten(VI) oxide surface
Authors: Adachi Kenta , Ura Yukimasa , Kanetada Naoya
Published: April 2018

Supramolecular organic dye–inorganic semiconductor nanocrystal assemblies are potentially useful in a broad range of technologies and applications, including photovoltaic systems, but the molecular basis of the adsorption of dye molecules onto the semiconductor surfaces remains poorly understood. Herein, we investigated the pH-dependent adsorption and conformational change of two cationic porphyrin stereoisomers [5,10-diphenyl-15,20-di([Formula: see text]-methyl-4-pyridyl)porphyrin (cis-DMPyP) and 5,15-diphenyl-10,20-di([Formula: see text]-methyl-4-pyridyl)porphyrin (trans-DMPyP)] on the tungsten(VI) oxide (WO[Formula: see text] colloid nanoparticle in aqueous media by means of UV-vis absorption spectroscopy. In accordance with the combination of a modified Langmuir adsorption model and Kasha’s exciton coupling model, the molecular orientation and stacking arrangement of DMPyP derivatives on the WO[Formula: see text] colloid surface are discussed in detail. In the trans-DMPyP/WO[Formula: see text] aqueous system, trans-DMPyP molecules adopted flat-on orientation with respect to the WO[Formula: see text] colloid surface and eventually formed head-to-tail [Formula: see text]-dimers regardless of pH conditions. cis-DMPyP molecules in the acidic system also lay flat-on and mainly formed [Formula: see text]-dimers on the WO[Formula: see text] colloid surface, whereas ones in the neutral system exhibited a dominant edge-on orientation and had a higher tendency to form face-to-face [Formula: see text]-dimers. Additionally, we have also convincingly demonstrated the pH-triggered switchable [Formula: see text]-stacking geometry of cis-DMPyP molecules from [Formula: see text]- to [Formula: see text]-dimer and vice versa on the WO[Formula: see text] colloid surface. Such findings will undoubtedly provide a pertinent guideline for the rational design of stimuli-responsive organic-inorganic materials.
Investigations of Reduction Effect of Vertical Wall on Dam-Break-Simulated Tsunami Surge Exerted on Wharf Piles
Authors: Chen Cheng , Melville Bruce W. , Nandasena N. A. K.
Published: April 2018

For a preliminary investigation of the impact of a tsunami surge on wharf piles, a tsunami flume was built in a laboratory, and a dam break flow was generated by a gate-reservoir system to simulate a tsunami surge. In addition, a vertical wall was installed in front of the wharf model so that its effect in reducing tsunami load could be studied. Five different tsunami surge strengths were generated by this gate-reservoir system. Wave transducers were used in the test flume to capture surge heights and velocities, and hence the surge front profiles, for different surge strengths. High-speed video cameras (210 frames per second) were used to record the flow motion of the tsunami surge, and pressure sensors (1000[Formula: see text]Hz in frequency) were used to capture the time histories of the tsunami pressure on the wharf piles. Four stages of tsunami surge motions were observed by this high-speed camera. Accordingly, the pressure time history can be divided into three phases. In our experimental range, pressures were influenced by surge height and wall height, but not by the wall position. Based on the dimensionless experimental data (pile heights, surge heights, vertical wall heights, and surge pressures), equations for estimating tsunami loads on wharf pile are proposed, expressing surge front (peak impact) pressure and quasi-steady pressure as functions of surge height, wall height, and pile height.
Morphological Segmentation and Part-of-Speech Tagging for the Arabic Heritage
Authors: Mohamed Emad
Published: April 2018

We annotate 60,000 words of Classical Arabic (CA) with topics in philosophy, religion, literature, and law with fine-grain segment-based morphological descriptions. We use these annotations for building a morphological segmenter and part-of-speech (POS) tagger for CA. With character-level classification and features from the word and its lexical context, the segmenter achieves a word accuracy of 96.8% with the main issue being a high rate of out-of-vocabulary words. A token-based POS tagger achieves an accuracy of 96.22% with 97.72% on known tokens despite the small size of the corpus. An error analysis shows that most of the tagging errors are results of segmentation and that quality improves with more data being added. The morphological segmenter and tagger have a wide range of potential applications in processing CA, a low-resource variety of the language.
Incorporating Prior Knowledge into Word Embedding for Chinese Word Similarity Measurement
Authors: Huang Degen , Pei Jiahuan , Zhang Cong , Huang Kaiyu , Ma Jianjun
Published: April 2018

Word embedding-based methods have received increasing attention for their flexibility and effectiveness in many natural language-processing (NLP) tasks, including Word Similarity (WS). However, these approaches rely on high-quality corpus and neglect prior knowledge. Lexicon-based methods concentrate on human’s intelligence contained in semantic resources, e.g., Tongyici Cilin, HowNet, and Chinese WordNet, but they have the drawback of being unable to deal with unknown words. This article proposes a three-stage framework for measuring the Chinese word similarity by incorporating prior knowledge obtained from lexicons and statistics into word embedding: in the first stage, we utilize retrieval techniques to crawl the contexts of word pairs from web resources to extend context corpus. In the next stage, we investigate three types of single similarity measurements, including lexicon similarities, statistical similarities, and embedding-based similarities. Finally, we exploit simple combination strategies with math operations and the counter-fitting combination strategy using optimization method. To demonstrate our system’s efficiency, comparable experiments are conducted on the PKU-500 dataset. Our final results are 0.561/0.516 of Spearman/Pearson rank correlation coefficient, which outperform the state-of-the-art performance to the best of our knowledge. Experiment results on Chinese MC-30 and SemEval-2012 datasets show that our system also performs well on other Chinese datasets, which proves its transferability. Besides, our system is not language-specific and can be applied to other languages, e.g., English.
Nonlinear Predictive Control System for Stiction Compensation in Electropneumatic Control Valves
Authors: Araújo M. E. U. J. , Gadelha J. R. T. , Santos W. M. , Maitelli A. L. , Araújo F. M. U.
Published: April 2018

This paper presents the implementation of a system that deals with static friction (stiction) in electropneumatic control valves, one of the most common nonlinearities that causes problems such as limit cycles and consequently wear of the valve and its moving parts, as well as losses in production and maintenance costs. This system is composed of a nonlinear predictive controller with adjustable constraints and an online database for estimation of the stiction parameters. The predictive controller uses constraints on the valve speed during its excursion, as well as constraints on the control signal to bring the valve to the desired position and slip it when necessary. The strategy adopted also showed robustness, being able to cope with changes in the spring and stiction parameters, which caused mismatch between the model and the controller and consequently loss of performance or even instability.
Luteinizing Hormone/Human Chorionic Gonadotropin Receptor Immunohistochemical Score Associated with Poor Prognosis in Endometrial Cancer Patients
Authors: Sorbi Flavia , Projetto Elisabetta , Turrini Irene , Baroni Gianna , Pillozzi Serena , Ghizzoni Viola , Vergoni Federica , Castiglione Francesca , Malentacchi Francesca , Fambrini Massimiliano , Noci Ivo
Published: April 2018

The aim of this study was to develop a scoring system of the immunohistochemical (IHC) expression of luteinizing hormone/human chorionic gonadotropin receptor (LHCG-R) in endometrial cancer (EC) patients. Nonconsecutive hysterectomy specimens containing EC collected from April 2013 to October 2015 were selected. Hematoxylin-eosin stained sections from each case were reviewed and representative sections from each tumor were selected. IHC staining was performed for the detection of LHCG-R. The percentage of stained cells and the staining intensity were assessed in order to develop an immunohistochemical score. Moreover, we examined the correlation of the score with grading and lymphovascular space invasion (LVSI). There was a statistically significant positive correlation between grading and IHC scoring (p=0.01) and a statistically significant positive correlation between LVSI and IHC score (p<0.01). In conclusion, we suggest that the immunohistochemical score presented here could be used as a marker of bad prognosis of EC patients. Nevertheless, further studies are needed in order to validate it. The study was registered in the Careggi Hospital public trials registry with the following number: 2013/0011391.