bluuebunny/crossref_metadata_2025 huggingface dataset:
Rate-Dependent Scaling of Dynamic Tensile Strength of Quasibrittle Structures
Authors: Le Jia-Liang , Eliáš Jan , Gorgogianni Anna , Vievering Joshua , Květoň Josef
Published: November 2017

This paper investigates the effect of strain rate on the scaling behavior of dynamic tensile strength of quasibrittle structures. The theoretical framework is anchored by a rate-dependent finite weakest link model. The model involves a rate-dependent length scale, which captures the transition from localized damage to diffused damage with an increasing strain rate. As a result, the model predicts a rate- and size-dependent probability distribution function of the nominal tensile strength. The transitional behavior of the strength distribution directly leads to the rate and size effects on the mean and standard deviation of the tensile strength. The model is verified by a series of stochastic discrete element simulations of dynamic fracture of aluminum nitride specimens. The simulations involve a set of geometrically similar specimens of various sizes subjected to a number of different strain rates. Both random microstructure geometry and fracture properties are considered in these simulations. The simulated damage pattern indicates that an increase in the strain rate results in a more diffusive cracking pattern, which supports the theoretical formulation. The simulated rate and size effects on the mean and standard deviation of the nominal tensile strength agree well with the predictions by the rate-dependent finite weakest link model.
Phase Transition of Temperature-Sensitive Hydrogel Under Mechanical Constraint
Authors: Shoujing Zheng , Zishun Liu
Published: November 2017

Temperature-sensitive hydrogel is blessed with outstanding properties which may be utilized for innovative appliance. However, this is not achievable if the phase transition property of it is not well understood. Under certain mechanical constraint or temperature stimuli, the hydrogel shows the phase transition, a very special phenomenon that has been study for decades. Those studies have cumulated many qualitative conclusions, yet the quantitative ones are still evasive. Using dynamic mechanical analysis (DMA), we have conducted experiments to quantitatively investigate this peculiar behavior. It is evident that the higher the temperature stimuli applied to hydrogel, the higher the stress which triggers phase transition. Based on the experimental results, a decision rule which predicts the stress triggering phase transition is proposed. Furthermore, theoretical study has also been carried out to study this phase transition phenomenon. With a proper fitting parameter and a transformation from referential state to free swelling state, we can compare the theoretical prediction of the stress–stretch curve with results from experiments. Besides experimental observations and theoretical analyses, another feature of this paper is to provide a numerical method to study phase transition under mechanical constraints.
Motion Responses of a Catenary-Taut-Hybrid Moored Single Module of a Semisubmersible Very Large Floating Structure in Multisloped Seabed
Authors: Wang Yiting , Wang Xuefeng , Xu Shengwen , Wang Lei
Published: November 2017

Motion responses of moored very large floating structures (VLFSs) in coastal regions are remarkably influenced by shallow water, seabed topography, and mooring system, which were given particular focus in this paper. A three-dimensional (3D) numerical model of a moored semisubmersible single module (SMOD) was described, and time domain simulated and experimentally validated. A catenary-taut-hybrid mooring system was adopted considering coastal space limitations. Large-scale catenary mooring lines were deployed on the deep water side, while taut chains were used on the shore side to decrease the anchor radius. Although the mooring system may induce a stiffness difference between the two sides, the effectiveness of the mooring system was demonstrated by time-domain simulation and model tests. The moored semisubmersible SMOD in shallow water exhibits significant low frequency characteristics. Water depth, asymmetric stiffness, and bottom topography effects were investigated by a series of sensitivity studies. The results show that these factors play an important role in motion responses of the moored SMOD, which can further conduce to better understandings on the hydrodynamic of the semisubmersible-type VLFSs.
An Efficient Convex Formulation for Model-Predictive Control on Wave-Energy Converters1
Authors: Zhong Qian , Yeung Ronald W.
Published: November 2017

Model-predictive control (MPC) has shown its strong potential in maximizing energy extraction for wave-energy converters (WECs) while handling hard constraints. However, the computational demand is known to be a primary concern for applying MPC in real time. In this work, we develop a cost function in which a penalty term on the slew rate of the machinery force is introduced and used to ensure the convexity of the cost function. Constraints on states and the input are incorporated. Such a constrained optimization problem is cast into a Quadratic Programming (QP) form and efficiently solved by a standard QP solver. The current MPC is found to have good energy-capture capability in both regular and irregular wave conditions, and is able to broaden favorably the bandwidth for capturing wave energy compared to other controllers in the literature. Reactive power required by the power-take-off (PTO) system is presented. The effects of the additional penalty term are discussed.
Automated Flexible Forming Strategy for Geometries With Multiple Features in Double-Sided Incremental Forming
Authors: Ndip-Agbor Ebot , Ehmann Kornel , Cao Jian
Published: November 2017

Double-sided incremental forming (DSIF) is a dieless sheet metal forming process that uses two generic tools to form a part of arbitrary geometry from a clamped sheet via the accumulation of small localized deformations. In DSIF, there is a need for an automatic toolpath generation method to separate geometric features coupled with a strategy to form these features in the correct sequence such that they can be accurately formed. Traditional CNC machining toolpaths are not suitable for DSIF because these toolpaths are designed for material removal processes, which do not have to account for the motion of the virgin material during the process. This paper presents a novel and simple way to represent geometric features in a hierarchical tree structure during z-height-based slicing along with algorithms to generate different forming strategies using this tree structure. The proposed approach is demonstrated through physical experiments by forming a complex part with multiple features.
Doppler spectra of airborne ultrasound forward scattered by the rough surface of open channel turbulent water flows
Authors: Dolcetti Giulio , Krynkin Anton
Published: November 2017

Experimental data are presented on the Doppler spectra of airborne ultrasound forward scattered by the rough dynamic surface of an open channel turbulent flow. The data are numerically interpreted based on a Kirchhoff approximation for a stationary random water surface roughness. The results show a clear link between the Doppler spectra and the characteristic spatial and temporal scales of the water surface. The decay of the Doppler spectra is proportional to the velocity of the flow near the surface. At higher Doppler frequencies the measurements show a less steep decrease of the Doppler spectra with the frequency compared to the numerical simulations. A semi-empirical equation for the spectrum of the surface elevation in open channel turbulent flows over a rough bed is provided. The results of this study suggest that the dynamic surface of open channel turbulent flows can be characterized remotely based on the Doppler spectra of forward scattered airborne ultrasound. The method does not require any equipment to be submerged in the flow and works remotely with a very high signal to noise ratio.
Dissemination of Multidrug-Resistant Proteus mirabilis Clones Carrying a Novel Integron-Borne
bla
IMP-1
in a Tertiary Hospital
Authors: Ramos Ana Carolina , Cayô Rodrigo , Carvalhaes Cecilia Godoy , Jové Thomas , da Silva Greice Pereira , Sancho Fernanda Maciel Paschoin , Chagas-Neto Thomas , Medeiros Eduardo Alexandrino Servolo , Gales Ana Cristina
Published: November 2017

This study aimed to characterize multidrug-resistant
Proteus mirabilis
clones carrying a novel class 1 integron-borne
bla
IMP-1
. In
1359
was inserted into a large conjugative plasmid that also carried
bla
CTX-M-2
. The production of carbapenemases in
Enterobacteriaceae
that are intrinsically resistant to polymyxins and tigecycline is very worrisome, representing a serious challenge to clinicians and infection control teams.
Characterization of Plasmodium Atg3-Atg8 Interaction Inhibitors Identifies Novel Alternative Mechanisms of Action in Toxoplasma gondii
Authors: Varberg Joseph M. , LaFavers Kaice A. , Arrizabalaga Gustavo , Sullivan William J.
Published: November 2017

Protozoan parasites, including the apicomplexan pathogens
Plasmodium falciparum
(which causes malaria) and
Toxoplasma gondii
(which causes toxoplasmosis), infect millions of people worldwide and represent major human disease burdens. Despite their prevalence, therapeutic strategies to treat infections caused by these parasites remain limited and are threatened by the emergence of drug resistance, highlighting the need for the identification of novel drug targets. Recently, homologues of the core autophagy proteins, including Atg8 and Atg3, were identified in many protozoan parasites. Importantly, components of the Atg8 conjugation system that facilitate the lipidation of Atg8 are required for both canonical and parasite-specific functions and are essential for parasite viability. Structural characterization of the
P. falciparum
Atg3-Atg8 (PfAtg3-Atg8) interaction has led to the identification of compounds that block this interaction. Additionally, many of these compounds inhibit
P. falciparum
growth
in vitro
, demonstrating the viability of this pathway as a drug target. Given the essential role of the Atg8 lipidation pathway in
Toxoplasma
, we sought to determine whether three PfAtg3-Atg8 interaction inhibitors identified in the Medicines for Malaria Venture Malaria Box exerted a similar inhibitory effect in
Toxoplasma
. While all three inhibitors blocked
Toxoplasma
replication
in vitro
at submicromolar concentrations, they did not inhibit
T. gondii
Atg8 (TgAtg8) lipidation. Rather, high concentrations of two of these compounds induced TgAtg8 lipidation and fragmentation of the parasite mitochondrion, similar to the effects seen following starvation and monensin-induced autophagy. Additionally, we report that one of the PfAtg3-Atg8 interaction inhibitors induces
Toxoplasma
egress and provide evidence that this is mediated by an increase in intracellular calcium in response to drug treatment.
A Simplified Derivative of Human Defensin 5 with Potent and Efficient Activity against Multidrug-Resistant Acinetobacter baumannii
Authors: Wang Cheng , Zhao Gaomei , Wang Song , Chen Yin , Gong Yali , Chen Shilei , Xu Yang , Hu Mengjia , Wang Xinmiao , Zeng Hao , Wang Aiping , Liu Dengqun , Su Yongping , Cheng Tianmin , Chen Fang , Wang Junping
Published: November 2017

The increasing incidence of multidrug-resistant
Acinetobacter baumannii
(MDR
Ab
) infections worldwide has necessitated the development of novel antibiotics. Human defensin 5 (HD5) is an endogenous peptide with a complex architecture and antibacterial activity against MDR
Ab
. In the present study, we attempted to simplify the structure of HD5 by removing disulfide bonds. We found that the Cys2-4 bond was most indispensable for HD5 to inactivate MDR
Ab
, although the antibacterial activity of the derivative was significantly attenuated. We then replaced the noncationic and nonhydrophobic residues with electropositive Arg to increase the antibacterial activity of HD5 derivative that contains a Cys2-4 bond, obtaining another derivative termed HD5d5. The in
vitro
antibacterial assay and irradiation-wound-infection animal experiment both showed that HD5d5 was much more effective than HD5 at eliminating MDR
Ab
. Further investigations revealed that HD5d5 efficiently bound to outer membrane lipid A and penetrated membranes, leading to bacterial collapse and peptide translocation. Compared to HD5, more HD5d5 molecules were located in the cytoplasm of MDR
Ab
, and HD5d5 was more efficient at reducing the activities of superoxide dismutase and catalase, causing the accumulation of reactive oxygen species that are detrimental to microbes. In addition, HD5 failed to suppress the pathogenic outer membrane protein A of
Acinetobacter baumannii
(
Ab
OmpA) at concentrations up to 50 μg/ml, whereas HD5d5 strongly bound to
Ab
OmpA and exhibited a dramatic toxin-neutralizing ability, thus expanding the repertoire of drugs that is available to treat MDR
Ab
infections.
In Vitro
Activities of Ceftaroline and Comparators against Streptococcus pneumoniae Isolates from U.S. Hospitals: Results from Seven Years of the AWARE Surveillance Program (2010 to 2016)
Authors: Pfaller Michael A. , Mendes Rodrigo E. , Duncan Leonard R. , Flamm Robert K. , Sader Helio S.
Published: November 2017

We evaluated trends in
Streptococcus pneumoniae
antimicrobial susceptibility in United States hospitals in the 2010 to 2016 period. A total of 8,768 clinical isolates from 47 medical centers were tested for susceptibility by broth microdilution methods. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) rates decreased from 25.7% and 12.4%, respectively, in 2010 to 17.7% and 3.6%, respectively, in 2016. The susceptibilities to most comparator antimicrobial agents increased, whereas the susceptibilities to ceftaroline, levofloxacin, linezolid, and tigecycline remained stable. Ceftaroline retained potent activity against
S. pneumoniae
(>99.9%) with no marked variations.
Proof-of-Principle Study in a Murine Lung Infection Model of Antipseudomonal Activity of Phage PEV20 in a Dry-Powder Formulation
Authors: Chang Rachel Yoon Kyung , Chen Ke , Wang Jiping , Wallin Martin , Britton Warwick , Morales Sandra , Kutter Elizabeth , Li Jian , Chan Hak-Kim
Published: November 2017

Bacteriophage therapy is a promising alternative treatment to antibiotics, as it has been documented to be efficacious against multidrug-resistant bacteria with minimal side effects. Several groups have demonstrated the efficacy of phage suspension
in vivo
to treat lung infections using intranasal delivery; however, phage dry-powder administration to the lungs has not yet been explored. Powder formulations provide potential advantages over a liquid formulation, including easy storage, transport, and administration. The purpose of this study was to assess the bactericidal activities of phage dry-powder formulations against multidrug-resistant (MDR) strain
Pseudomonas aeruginosa
FADDI-PA001 in a mouse lung infection model. Phage PEV20 spray dried with lactose and leucine produced an inhalable powder at a concentration of 2 × 10
7
PFU/mg.
P. aeruginosa
lung infection was established by intratracheal administration of the bacterial suspension to neutropenic mice. At 2 h after the bacterial challenge, the infected mice were treated with 2 mg of the phage powder using a dry-powder insufflator. At 24 h after the phage treatment, the bacterial load in the lungs was decreased by 5.3 log
10
(
P
< 0.0005) in the phage-treated group compared with that in the nontreated group. Additionally, the phage concentration in the lungs was increased by 1 log
10
at 24 h in the treated group. These results demonstrate the feasibility of a pulmonary delivery of phage PEV20 dry-powder formulation for the treatment of lung infection caused by antibiotic-resistant
P. aeruginosa
.
Fluconazole-Resistant Candida auris Is Susceptible to Salivary Histatin 5 Killing and to Intrinsic Host Defenses
Authors: Pathirana Ruvini U. , Friedman Justin , Norris Hannah L. , Salvatori Ornella , McCall Andrew D. , Kay Jason , Edgerton Mira
Published: November 2017

Candida auris
is a newly identified species causing invasive candidemia and candidiasis. It has broad multidrug resistance (MDR) not observed for other pathogenic
Candida
species. Histatin 5 (Hst 5) is a well-studied salivary cationic peptide with significant antifungal activity against
Candida albicans
and is an attractive candidate for treating MDR fungi, since antimicrobial peptides induce minimal drug resistance. We investigated the susceptibility of
C. auris
to Hst 5 and neutrophils, two first-line innate defenses in the human host. The majority of
C. auris
clinical isolates, including fluconazole-resistant strains, were highly sensitive to Hst 5: 55 to 90% of cells were killed by use of 7.5 μM Hst 5. Hst 5 was translocated to the cytosol and vacuole in
C. auris
cells; such translocation is required for the killing of
C. albicans
by Hst 5. The inverse relationship between fluconazole resistance and Hst 5 killing suggests different cellular targets for Hst 5 than for fluconazole.
C. auris
showed higher tolerance to oxidative stress than
C. albicans
, and higher survival within neutrophils, which correlated with resistance to oxidative stress
in vitro
. Thus, resistance to reactive oxygen species (ROS) is likely one, though not the only, important factor in the killing of
C. auris
by neutrophils. Hst 5 has broad and potent candidacidal activity, enabling it to combat MDR
C. auris
strains effectively.
In Vitro
Activity of the Siderophore Cephalosporin, Cefiderocol, against Carbapenem-Nonsusceptible and Multidrug-Resistant Isolates of Gram-Negative Bacilli Collected Worldwide in 2014 to 2016
Authors: Hackel Meredith A. , Tsuji Masakatsu , Yamano Yoshinori , Echols Roger , Karlowsky James A. , Sahm Daniel F.
Published: November 2017

The
in vitro
activity of the investigational siderophore cephalosporin, cefiderocol (formerly S-649266), was determined against a 2014–2016, 52-country, worldwide collection of clinical isolates of carbapenem-nonsusceptible
Enterobacteriaceae
(
n
= 1,022), multidrug-resistant (MDR)
Acinetobacter baumannii
(
n
= 368), MDR
Pseudomonas aeruginosa
(
n
= 262),
Stenotrophomonas maltophilia
(
n
= 217), and
Burkholderia cepacia
(
n
= 4) using the Clinical and Laboratory Standards Institute (CLSI) standard broth microdilution method. Iron-depleted cation-adjusted Mueller-Hinton broth (ID-CAMHB), prepared according to a recently approved (2017), but not yet published, CLSI protocol, was used to test cefiderocol; all other antimicrobial agents were tested using CAMHB. The concentration of cefiderocol inhibiting 90% (MIC
90
) of isolates of carbapenem-nonsusceptible
Enterobacteriaceae
was 4 μg/ml; cefiderocol MICs ranged from 0.004 to 32 μg/ml, and 97.0% (991/1,022) of isolates demonstrated cefiderocol MICs of ≤4 μg/ml. The MIC
90
s for cefiderocol for MDR
A. baumannii
, MDR
P. aeruginosa
, and
S. maltophilia
were 8, 1, and 0.25 μg/ml, respectively, with 89.7% (330/368), 99.2% (260/262), and 100% (217/217) of isolates demonstrating cefiderocol MICs of ≤4 μg/ml. Cefiderocol MICs for
B. cepacia
ranged from 0.004 to 8 μg/ml. We conclude that cefiderocol demonstrated potent
in vitro
activity against a 2014–2016, worldwide collection of clinical isolates of carbapenem-nonsusceptible
Enterobacteriaceae
, MDR
A. baumannii
, MDR
P. aeruginosa
,
S. maltophilia
, and
B. cepacia
isolates as 96.2% of all (1,801/1,873) isolates tested had cefiderocol MICs of ≤4 μg/ml.
Comparative
In Vitro
Activities of Relebactam, Imipenem, the Combination of the Two, and Six Comparator Antimicrobial Agents against 432 Strains of Anaerobic Organisms, Including Imipenem-Resistant Strains
Authors: Goldstein Ellie J. C. , Citron Diane M. , Tyrrell Kerin L. , Leoncio Eliza , Merriam C. Vreni
Published: November 2017

Relebactam is an important beta-lactamase inhibitor for certain aerobic organisms, but alone it has no antianaerobic activity, with most anaerobes having MICs of ≥32 μg/ml with the exception of a very few strains. There was no enhancement or antagonism of imipenem activity with the addition of relebactam, including activity against imipenem-resistant strains. The relebactam-imipenem combination had excellent overall activity against the anaerobes tested.
Revisiting Activation of and Mechanism of Resistance to Compound IQG-607 in Mycobacterium tuberculosis
Authors: Abbadi Bruno L. , Villela Anne D. , Rodrigues-Junior Valnês S. , Subtil Fernanda T. , Dalberto Pedro F. , Pinheiro Ana P. S. , Santos Diógenes S. , Machado Pablo , Basso Luiz A. , Bizarro Cristiano V.
Published: November 2017

IQG-607 is a metal complex previously reported as a promising anti-tuberculosis (TB) drug against isoniazid (INH)-resistant strains of
Mycobacterium tuberculosis
. Unexpectedly, we found that INH-resistant clinical isolates were resistant to IQG-607. Spontaneous mutants resistant to IQG-607 were subjected to whole-genome sequencing, and all sequenced colonies carried alterations in the
katG
gene. The
katG
(S315T) mutation was sufficient to confer resistance to IQG-607 in both MIC assays and inside macrophages. Moreover, overexpression of the InhA(S94A) protein caused IQG-607's resistance.
Salmonella enterica Serovar Typhimurium Alters the Extracellular Proteome of Macrophages and Leads to the Production of Proinflammatory Exosomes
Authors: Hui Winnie W. , Hercik Kamil , Belsare Sayali , Alugubelly Navatha , Clapp Beata , Rinaldi Carlos , Edelmann Mariola J.
Published: November 2017

Salmonella enterica
serovar Typhimurium is a Gram-negative bacterium, which can invade and survive within macrophages. Pathogenic salmonellae induce the secretion of specific cytokines from these phagocytic cells and interfere with the host secretory pathways. In this study, we describe the extracellular proteome of human macrophages infected with
S
. Typhimurium, followed by analysis of canonical pathways of proteins isolated from the extracellular milieu. We demonstrate that some of the proteins secreted by macrophages upon
S
. Typhimurium infection are released via exosomes. Moreover, we show that infected macrophages produce CD63
+
and CD9
+
subpopulations of exosomes at 2 h postinfection. Exosomes derived from infected macrophages trigger the Toll-like receptor 4-dependent release of tumor necrosis factor alpha (TNF-α) from naive macrophages and dendritic cells, but they also stimulate secretion of such cytokines as RANTES, IL-1ra, MIP-2, CXCL1, MCP-1, sICAM-1, GM-CSF, and G-CSF. Proinflammatory effects of exosomes are partially attributed to lipopolysaccharide, which is encapsulated within exosomes. In summary, we show for the first time that proinflammatory exosomes are formed in the early phase of macrophage infection with
S
. Typhimurium and that they can be used to transfer cargo to naive cells, thereby leading to their stimulation.
Mutations in Sugar-Nucleotide Synthesis Genes Restore Holdfast Polysaccharide Anchoring to Caulobacter crescentus Holdfast Anchor Mutants
Authors: Hardy Gail G. , Toh Evelyn , Berne Cécile , Brun Yves V.
Published: November 2017

Attachment is essential for microorganisms to establish interactions with both biotic and abiotic surfaces. Stable attachment of
Caulobacter crescentus
to surfaces requires an adhesive polysaccharide holdfast, but the exact composition of the holdfast is unknown. The holdfast is anchored to the cell envelope by outer membrane proteins HfaA, HfaB, and HfaD.
H
old
f
ast
a
nchor gene mutations result in holdfast shedding and reduced cell adherence. Translocation of HfaA and HfaD to the cell surface requires HfaB. The Wzx homolog HfsF is predicted to be a bacterial polysaccharide flippase. An
hfsF
deletion significantly reduced the amount of holdfast produced per cell and slightly reduced adherence. A Δ
hfsF
Δ
hfaD
double mutant was completely deficient in adherence. A suppressor screen that restored adhesion in the Δ
hfsF
Δ
hfaD
mutant identified mutations in three genes:
wbqV
,
rfbB
, and
rmlA
. Both WbqV and RfbB belong to a family of nucleoside-diphosphate epimerases, and RmlA has similarity to nucleotidyltransferases. The loss of
wbqV
or
rfbB
in the Δ
hfsF
Δ
hfaD
mutant reduced holdfast shedding but did not restore holdfast synthesis to parental levels. Loss of
wbqV
or
rfbB
did not restore adherence to a Δ
hfsF
mutant but did restore adherence and holdfast anchoring to a Δ
hfaD
mutant, confirming that suppression occurs through restoration of holdfast anchoring. The adherence and holdfast anchoring of a Δ
hfaA ΔhfaD
mutant could be restored by
wbqV
or
rfbB
mutation, but such mutations could not suppress these phenotypes in the Δ
hfaB
mutant. We hypothesize that HfaB plays an additional role in holdfast anchoring or helps to translocate an unknown factor that is important for holdfast anchoring.

IMPORTANCE
Biofilm formation results in increased resistance to both environmental stresses and antibiotics.
Caulobacter crescentus
requires an adhesive holdfast for permanent attachment and biofilm formation, but the exact mechanism of polysaccharide anchoring to the cell and the holdfast composition are unknown. Here we identify novel polysaccharide genes that affect holdfast anchoring to the cell. We identify a new role for the holdfast anchor protein HfaB. This work increases our specific knowledge of the polysaccharide adhesin involved in
Caulobacter
attachment and the general knowledge regarding production and anchoring of polysaccharide adhesins by bacteria. This work also explores the interactions between different polysaccharide biosynthesis and secretion systems in bacteria.
Comparative Genomics of Myxobacterial Chemosensory Systems
Authors: Sharma Gaurav , Khatri Indu , Subramanian Srikrishna
Published: November 2017

Chemosensory systems (CSS) are among the most complex organizations of proteins functioning cooperatively to regulate bacterial motility and other cellular activities. These systems have been studied extensively in bacteria, and usually, they are present as a single system. Eight CSS, the highest number in bacteria, have been reported in
Myxococcus xanthus
DK1622 and are involved in coordinating diverse functions. Here, we have explored and compared the CSS in all available genomes of order
Myxococcales. Myxococcales
members contain 97 to 476 two-component system (TCS) proteins, which assist the bacteria in surviving and adapting to varying environmental conditions. The number of myxobacterial CSS ranges between 1 and 12, with the largest number in family
Cystobacteraceae
and the smallest in
Nannocystaceae
. CheA protein was used as a phylogenetic marker to infer evolutionary relatedness between different CSS, and six novel CSS (“extra CSS” [ECSS]) were thus identified in the myxobacteria besides the previously reported Che1 to Che8 systems from
M. xanthus
. Che1 to Che8 systems are monophyletic to deltaproteobacteria, whereas the newly identified ECSS form separate clades with different bacterial classes. The comparative modular organization was concordant with the phylogeny. Four clusters lacking CheA proteins were also identified via CheB-based phylogenetic analysis and were categorized as accessory CSS (ACSS). In
Archangium
, an orphan CSS was identified, in which both CheA and CheB were absent. The novel, accessory, and orphan multimodular CSS identified here suggest the emergence of myxobacterial CSS and could assist in further characterizing their roles.

IMPORTANCE
This study is focused on chemosensory systems (CSS), which help the bacterium in directing its movement toward or away from chemical gradients. CSS are present as a single system in most of the bacteria except in some groups, including
Myxococcus xanthus
, which has 8 CSS, the highest number reported to date. This is the first comprehensive study carrying out a comparative analysis of the 22 available myxobacterial genomes, which suggests the evolutionary diversity of these systems. We are interested in understanding the distribution of CSS within all known myxobacteria and their probable evolution.
Patients’ initial steps to cancer diagnosis in Denmark, England and Sweden: what can a qualitative, cross-country comparison of narrative interviews tell us about potentially modifiable factors?
Authors: MacArtney John , Malmström Marlene , Overgaard Nielsen Trine , Evans Julie , Bernhardson Britt-Marie , Hajdarevic Senada , Chapple Alison , Eriksson Lars E , Locock Louise , Rasmussen Birgit , Vedsted Peter , Tishelman Carol , Andersen Rikke Sand , Ziebland Sue
Published: November 2017

Objectives

To illuminate patterns observed in International Cancer Benchmarking Programme studies by extending understanding of the various influences on presentation and referral with cancer symptoms.

Design

Cross-country comparison of Denmark, England and Sweden with qualitative analysis of in-depth interview accounts of the prediagnostic process in lung or bowel cancer.

Participants

155 women and men, aged between 35 and 86 years old, diagnosed with lung or bowel cancer in 6 months before interview.

Setting

Participants recruited through primary and secondary care, social media and word of mouth. Interviews collected by social scientists or nurse researchers during 2015, mainly in participants’ homes.

Results

Participants reported difficulties in interpreting diffuse bodily sensations and symptoms and deciding when to consult. There were examples of swift referrals by primary care professionals in all three countries. In all countries, participants described difficulty deciding if and when to consult, highlighting concerns about access to general practitioner appointments and overstretched primary care services, although this appears less prominent in the Swedish data. It was not unusual for there to be more than one consultation before referral and we noted two distinct patterns of repeated consultation: (1) situations where the participant left the primary care consultation with a plan of action about what should happen next; (2) participants were unclear about under which conditions to return to the doctors. This second pattern sometimes extended over many weeks during which patients described uncertainty, and sometimes frustration, about if and when they should return and whether there were any other feasible investigations. The latter pattern appeared more evident in the interviews in England and Denmark than Sweden.

Conclusion

We suggest that if clear action plans, as part of safety netting, were routinely used in primary care consultations then uncertainty, false reassurance and the inefficiency and distress of multiple consultations could be reduced.
Women and substance use: a qualitative study on sexual and reproductive health of women who use drugs in Delhi, India
Authors: Sharma Vartika , Sarna Avina , Tun Waimar , Saraswati Lopamudra Ray , Thior Ibou , Madan Ira , Luchters Stanley
Published: November 2017

Objectives

To explore contextual factors that increase vulnerabilities to negative sexual and reproductive health (SRH) outcomes and possible differences in SRH-related behaviours and the needs of women who use drugs (WUD) through non-injecting and injecting routes.

Design

Qualitative study design using semi-structured in-depth interviews.

Participants

Twenty women who injected drugs in the past 3 months and 28 women who reported using drugs through non-injecting routes in the past 1 month.

Setting

Interviews were conducted at community-based, drop-in centres in Delhi, India.

Results

Study findings illustrate that WUD were sexually active and had multiple sex partners including clients of sex work. Transient relationships were reported and many participants engaged in unsafe sex. Factors which affected safe sex behaviours included: gender power imbalance, limited agency for decision-making, lack of accurate information for correct self-risk assessment, and being under the influence of drugs. Despite high awareness, low and inconsistent contraceptive use was reported. Some participants were coerced to conceive while a few others reported their inability to conceive. Violence was a key determinant for SRH outcomes. Perception of certain adverse health outcomes (such as infertility) to be ‘common and expected among WUD’ influenced access to healthcare. Further, healthcare providers’ stigmatising attitudes and lack of women-centric services deterred women from uptake of healthcare services.

Conclusion

Findings highlight that SRH-related behaviours and needs of this group are a complex interplay of multiple determinants which need to be addressed at all levels: individual, family, community and institutional. It is imperative to roll out a ‘one-stop-shop’ for a comprehensive package of health services. Expansion of existing drop-in-centres could be considered for setting-up community-based women-centric services with appropriate linkage to drug dependence treatment and reproductive health services.
Resection of pancreatic cancer in Europe and USA: an international large-scale study highlighting large variations
Authors: Huang Lei , Jansen Lina , Balavarca Yesilda , Molina-Montes Esther , Babaei Masoud , van der Geest Lydia , Lemmens Valery , Van Eycken Liesbet , De Schutter Harlinde , Johannesen Tom B , Fristrup Claus W , Mortensen Michael B , Primic-Žakelj Maja , Zadnik Vesna , Becker Nikolaus , Hackert Thilo , Mägi Margit , Cassetti Tiziana , Sassatelli Romano , Grützmann Robert , Merkel Susanne , Gonçalves Ana F , Bento Maria J , Hegyi Péter , Lakatos Gábor , Szentesi Andrea , Moreau Michel , van de Velde Tony , Broeks Annegien , Sant Milena , Minicozzi Pamela , Mazzaferro Vincenzo , Real Francisco X , Carrato Alfredo , Molero Xavier , Besselink Marc G , Malats Núria , Büchler Markus W , Schrotz-King Petra , Brenner Hermann
Published: November 2017

Objective

Resection can potentially cure resectable pancreatic cancer (PaC) and significantly prolong survival in some patients. This large-scale international study aimed to investigate variations in resection for PaC in Europe and USA and determinants for its utilisation.

Design

Data from six European population-based cancer registries and the US Surveillance, Epidemiology, and End Results Program database during 2003–2016 were analysed. Age-standardised resection rates for overall and stage I–II PaCs were computed. Associations between resection and demographic and clinical parameters were assessed using multivariable logistic regression models.

Results

A total of 153 698 records were analysed. In population-based registries in 2012–2014, resection rates ranged from 13.2% (Estonia) to 21.2% (Slovenia) overall and from 34.8% (Norway) to 68.7% (Denmark) for stage I–II tumours, with great international variations. During 2003–2014, resection rates only increased in USA, the Netherlands and Denmark. Resection was significantly less frequently performed with more advanced tumour stage (ORs for stage III and IV versus stage I–II tumours: 0.05–0.18 and 0.01–0.06 across countries) and increasing age (ORs for patients 70–79 and ≥80 versus those <60 years: 0.37–0.63 and 0.03–0.16 across countries). Patients with advanced-stage tumours (stage III–IV: 63.8%–81.2%) and at older ages (≥70 years: 52.6%–59.5%) receiving less frequently resection comprised the majority of diagnosed cases. Patient performance status, tumour location and size were also associated with resection application.

Conclusion

Rates of PaC resection remain low in Europe and USA with great international variations. Further studies are warranted to explore reasons for these variations.
Cutaneous vasomotor adaptation following repeated, isothermal heat exposures: evidence of adaptation specificity
Authors: Notley Sean R. , Taylor Elizabeth A. , Ohnishi Norikazu , Taylor Nigel A.S.
Published: November 2017

Unequivocal enhancement of cutaneous vasomotor function has yet to be demonstrated following heat acclimation, possibly because the adaptation stimulus was not sustained, or because thermoeffector function was not assessed at equivalent deep-body temperatures. Therefore, forearm and local cutaneous vascular conductances were evaluated during exercise eliciting matched deep-body temperatures (37.5 °C, 38.5 °C), before and after isothermal heat acclimation. Both indices increased (21% and 25%), confirming cutaneous vasomotor adaptation can occur, provided those experimental design specifications are satisfied.
Honey bee survival is affected by interactions between field-relevant rates of fungicides and insecticides used in apple and blueberry production
Authors: Manning Paul , Ramanaidu Krilen , Cutler G. Christopher
Published: November 2017

Certain compounds of low toxicity can increase the susceptibility of an organism to toxic substances; this is known as potentiation. Demethylation inhibiting (DMI) fungicides can potentiate insecticides by impairing the production of detoxification enzymes. As both DMI fungicides and insecticides can be used near or during crop bloom, the combination may be hazardous if exposed to pollinators. Using pesticides used in blueberry or apple production, we conducted laboratory bioassays to test how combinations of field-relevant concentrations of DMI fungicides and insecticides affected honey bee ( Apis mellifera) survival. We found propiconazole, a DMI fungicide, potentiated the toxicity of the neonicotinoid insecticide acetamiprid. We found no evidence of propiconazole potentiating field-relevant concentrations of the spinosyn insecticide spinetoram. We also found that the DMI fungicide flusilazole potentiated spinetoram but not acetamiprid. A fungicidal formulation combining pyraclostrobin and boscalid did not potentiate either insecticide. Given that bees can be simultaneously exposed to multiple pesticides, understanding the potential of pesticide potentiation and synergism may help mitigate risks associated with pollinator exposure to pesticides.
Ethanol-Induced Alterations of T Cells and Cytokines after Surgery in a Murine Infection Model
Authors: Lanzke Nadine , Menk Mario , von Haefen Clarissa , Sargsyan Lilit , Scharf Bianca , Wernecke Klaus-Dieter , Spies Claudia D.
Published: November 2017

Background. Interactions between alcohol, infection, and surgery and their effect on differentiation and functionality of T helper cells are not yet completely understood. We hypothesized that alcohol and surgery disturb differentiation of T helper cells and contribute to an impaired immune response.Methods. Mice were treated with alcohol for two weeks. Saline treatment served as control. Clinical performance and weight were assessed. On day 14, a median laparotomy was performed and animals were challenged withKlebsiella pneumoniaeintranasally. Bacterial load was determined in lungs and blood. T helper cell subpopulations and the released cytokines were assessed in lungs, spleens, and plasma. Key transcription factors of T cell differentiation were evaluated.Results. Alcohol significantly impaired clinical appearance and body weight of animals with postsurgical infection(p<0.05). Bacterial load was significantly higher after alcohol treatment(p<0.05). T helper cell subsets and released cytokine levels were significantly altered in lung, but not in spleen. Expression of transcription factors of T helper cell lineage commitment did not translate into different counts of T helper cells.Conclusions. Alcohol and surgery lead to significant cellular and functional modulations of T helper cells during postsurgical infection. These effects may contribute to an impaired immune response after surgery.
On Hofstadter Heart Sequences
Authors: Alkan Altug , Fox Nathan , Aybar O. Ozgur
Published: November 2017

The Hofstadter Q-sequence and the Hofstadter-Conway $10000 sequence are perhaps the two best known examples of meta-Fibonacci sequences. In this paper, we explore an unexpected connection between them. When the Q-sequence is subtracted from the Conway sequence, a chaotic pattern of heart-shaped figures emerges. We use techniques of Pinn and Tanny et al. to explore this sequence. Then, we introduce and analyze an apparent relative of the Q-sequence and illustrate how it also generates heart patterns when subtracted from the Conway sequence.
Treatment of an Esophageal Stricture in a 1-Month-Old Miniature Shetland Colt
Authors: Nijdam P. , Elmas C. , Fugazzola M. C.
Published: November 2017

A 1-month-old Miniature Shetland colt was presented to the Burg Müggenhausen Equine Clinic. Primary complaints were regurgitation of milk, bilateral white nasal discharge, and weakness. Physical examination, endoscopy of the esophagus, and contrast radiography led to the diagnosis of an esophageal stricture and aspiration pneumonia. Surgical treatment by means of an esophagomyotomy was performed. The foal improved only temporarily and multiple sessions of endoscopic balloon dilation of the esophagus were performed afterwards. 12 months after the final treatment the foal was healthy and had no complaints regarding esophageal function.
Theoretical Analysis on the Nonlinear Free Vibration of a Tri-Cross String
Authors: Pan Bo , Tang Jingda , Tarumi Ryuichi , Shang Fulin , Wang Yanbo , Zhang Weijun , Zhang Xueyan
Published: November 2017

Here we present a theoretical analysis on the nonlinear free vibration of a tri-cross string system, which is an element of space net-antennas. We derived the governing equations from Hamilton’s principle and obtained a linearized solution by the standard perturbation method. The semi-analytical solutions of the governing equations have not been provided referring to the solution of plate vibrating problem. This analysis revealed that natural frequencies of the tri-cross string depend on the vibration amplitude due to the geometrical nonlinearity in the constitutive equation. The geometric parameters, such as the diameters and the lengths of the constituent strings, also affect the frequency through the nonlinearity of the tri-cross string. The nonlinear natural frequency shows coupled characteristic; that is, the natural frequency of the tri-cross string varies with that of the constituent strings, but the contribution of each constituent string to the natural frequency is in different proportions.
Trajectory Optimization of Spray Painting Robot for Complex Curved Surface Based on Exponential Mean Bézier Method
Authors: Chen Wei , Liu Junjie , Tang Yang , Huan Jian , Liu Hao
Published: November 2017

Automated tool trajectory planning for spray painting robots is still a challenging problem, especially for a large complex curved surface. This paper presents a new method of trajectory optimization for spray painting robot based on exponential mean Bézier method. The definition and the three theorems of exponential mean Bézier curves are discussed. Then a spatial painting path generation method based on exponential mean Bézier curves is developed. A new simple algorithm for trajectory optimization on complex curved surfaces is introduced. A golden section method is adopted to calculate the values. The experimental results illustrate that the exponential mean Bézier curves enhanced flexibility of the path planning, and the trajectory optimization algorithm achieved satisfactory performance. This method can also be extended to other applications.
Contribution of Atmospheric Advection to the Amplified Winter Warming in the Arctic North Atlantic Region
Authors: Dahlke Sandro , Maturilli Marion
Published: November 2017

Arctic Amplification of climate warming is caused by various feedback processes in the atmosphere-ocean-ice system and yields the strongest temperature increase during winter in the Arctic North Atlantic region. In our study, we attempt to quantify the advective contribution to the observed atmospheric warming in the Svalbard area. Based on radiosonde measurements from Ny-Ålesund, a strong dependence of the tropospheric temperature on the synoptic flow direction is revealed. Using FLEXTRA backward trajectories, an increase of advection from the lower latitude Atlantic region towards Ny-Ålesund is found that is attributed to a change in atmospheric circulation patterns. We find that about one-quarter (0.45 K per decade) of the observed atmospheric winter near surface warming trend in the North Atlantic region of the Arctic (2 K per decade) is due to increased advection of warm and moist air from the lower latitude Atlantic region, affecting the entire troposphere.
A Novel Construction of Substitution Box Involving Coset Diagram and a Bijective Map
Authors: Razaq Abdul , Yousaf Awais , Shuaib Umer , Siddiqui Nasir , Ullah Atta , Waheed Adil
Published: November 2017

The substitution box is a basic tool to convert the plaintext into an enciphered format. In this paper, we use coset diagram for the action of PSL(2,Z) on projective line over the finite field GF29 to construct proposed S-box. The vertices of the cost diagram are elements of GF29 which can be represented by powers of α, where α is the root of irreducible polynomial px=x9+x4+1 over Z2. Let GF⁎29 denote the elements of GF29 which are of the form of even powers of α. In the first step, we construct a 16×16 matrix with the elements of GF⁎29 in a specific order, determined by the coset diagram. Next, we consider h:GF⁎29⟶GF28 defined by hα2n=ωn to destroy the structure of GF28. In the last step, we apply a bijective map g on each element of the matrix to evolve proposed S-box. The ability of the proposed S-box is examined by different available algebraic and statistical analyses. The results are then compared with the familiar S-boxes. We get encouraging statistics of the proposed box after comparison.
Nonpenetrating Damage Identification Using Hybrid Lamb Wave Modes from Hilbert-Huang Spectrum in Thin-Walled Structures
Authors: Wang Zijian , Qiao Pizhong , Shi Binkai
Published: November 2017

Lamb waves have shown promising advantages for damage identification in thin-walled structures. Multiple modes of Lamb wave provide diverse sensitivities to different types of damage. To sufficiently utilize damage-related wave features, damage indices were developed by using hybrid Lamb wave modes from Hilbert-Huang spectra. Damage indices were defined as surface integrals of Hilbert-Huang spectra on featured regions determined by time and frequency windowing. The time windowing was performed according to individual propagation velocity of different Lamb wave mode, while the frequency windowing was performed according to the frequency of excitation. By summing damage indices for all transmitter-receiver pairs, pixels were calculated to reconstruct a damage map to characterize the degree of damage at each location on structure. Both numerical and experimental validations were conducted to identify a nonpenetrating damage. The results demonstrated that the proposed damage indices using hybrid Lamb wave modes are more sensitive and robust than the one using single Lamb wave mode.
Consensus of Switched Multiagent Systems under Relative State Constraints
Authors: Wang Qingling
Published: November 2017

The consensus problem is presented for the switched multiagent system (MAS), where the MAS is switched between continuous- and discrete-time systems with relative state constraints. With some standard assumptions, we obtain the fact that the switched MAS with relative state constraints can achieve consensus under both fixed undirected graphs and switching undirected graphs. Furthermore, based on the absolute average value of initial states, we propose sufficient conditions for consensus of the switched MAS. The challenge of this study is that relative state constraints are considered, which will make the consensus problem much more complex. One of the main contributions is that, for the switched MAS with relative state constraints, we explore the solvability of the consensus problem. Finally, we present two simulation examples to show the effectiveness of the results.