bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of mechanical properties of porous CFRP specimens by ANNs and X-ray CT data
Authors: Stamopoulos Antonios , Tserpes Konstantinos , Dentsoras Argyris
Published: August 2018

Carbon fiber reinforced plastics (CFRPs) have evolved into the primary material for several lightweight structures. However, despite their extensive use and the quality amelioration, CFRPs remain susceptible to a variety of manufacturing defects, the most common of which are the pores. Predictive tools capable of correlating the mechanical properties of CFRP parts with the characteristics of defects as derived from non-destructive testing (NDT) techniques or even further with the manufacturing parameters could serve as an effective tool for the quality control of CFRP structural parts. In the present paper, the characteristics of pores as evaluated by X-ray Computed Tomography (CT) have been correlated with the matrixdominated mechanical properties of unidirectional porous CFRP specimens using Artificial Neural Networks (ANN). Thirty (30) porosity scenarios have been created and given as input to the numerical model. That multi-scale numerical model, which had been validated experimentally, has been used for training the ANN model. The predictions of the ANN agree very well with results from mechanical tests. Moving one step forward, a second ANN has been developed to correlate the autoclave pressure directly with the mechanical properties of the CFRP specimens. The validity of the latter ANN depends on the accuracy of the relation between the autoclave pressure and the characteristics of the pores. The present work represents a step towards the development of effective quality control tools for composite materials.
Finite Element Simulation of the Thermo-mechanical Response of Graphene Reinforced Nanocomposites
Authors: Tsiamaki Androniki S. , Anifantis Nick K.
Published: August 2018

The research for new materials that can withstand extreme temperatures and present good mechanical behavior is of great importance. The interest is highly focused on the utilization of composites reinforced by nanomaterials. To cope with this goal the present work studies the mechanical response of graphene reinforced nanocomposite structures subjected to temperature changes. A computational finite element model has been developed that accounts for both the reinforcement and the matrix material phases. The model developed is based on both the continuum theory and the molecular mechanics theory, for the simulation of the three different material phases of the composite, respectively, i.e. the matrix, the intermediate transition phase and the reinforcement. Considering this model, the mechanical response of an appropriate representative volume element of the nanocomposite is simulated under various temperature changes. The study involves different types of reinforcement composed from either monolayer or multilayer graphene sheets. Apart from the investigation of the behavior of a nanocomposite with each particular type of the reinforcement, comparisons are also presented between them in order to reveal optimized material combinations. The principal parameters taken into consideration, which contribute also to the mechanical behavior of the nanocomposite, are its size, the sheet multiplicity as well as the volume fraction.
Fabrication of carbon nanotube-reinforced mortar specimens: evaluation of mechanical and pressure-sensitive properties
Authors: Karaxi Evangelia K. , Kanellopoulou Irene A. , Karatza Anna , Kartsonakis Ioannis A. , Charitidis Costas A.
Published: August 2018

Carbon-based nanomaterials are promising reinforcing elements for the development of “smart” self-sensing cementitious composites due to their exceptional mechanical and electrical properties. Significant research efforts have been committed on the synthesis of cement-based composite materials reinforced with carbonaceous nanostructures, covering every aspect of the production process (type of nanomaterial, mixing process, electrode type, measurement methods etc.). In this study, the aim is to develop a well-defined repeatable procedure for the fabrication as well as the evaluation of pressure-sensitive properties of intrinsically self-sensing cementitious composites incorporating carbon- based nanomaterials. Highly functionalized multi-walled carbon nanotubes with increased dispersibility in polar media were used in the development of advanced reinforced mortar specimens which increased their mechanical properties and provided repeatable pressure-sensitive properties.
Life cycle assessment and cost analysis evaluation of a helicopter's canopy production using different manufacturing processes
Authors: Loukopoulos Andreas , Katsiropoulos Christos , Pantelakis Spiros
Published: August 2018

In the present work, Life Cycle analysis (LCA) and Life cycle costing (LCC) models were developed in order to quantify the environmental footprint and cost and thus compare different manufacturing scenarios associated with the production of aeronautical structural components. To validate the models developed, they were implemented for the case of a helicopter's canopy processed by two techniques commonly used in aeronautics, namely the autoclave and the Resin Transfer moulding (RTM). The canopy was assumed to be made of a carbon fiber reinforced thermosetting material. Using the models developed the expected environmental and cost benefits by involving the RTM technique have been quantified.
Polyamide 12/E-glass Fabric Composite Production with Dip-coating
Authors: Bekem Aylin , Unal Ahmet
Published: August 2018

In this study PA12 was reinforced with E-glass woven fabric by dip-coating. PA12 powder and ethanol suspensions were prepared with ratios at 30, 40 and 50% of powder to obtain different fibre contents. Coated fabrics were laid-up and kept in oven at 60°C to evaporate ethanol. Then it was placed in a compression mould and pressed. Obtained laminates were subjected to tensile, bending and impact tests. Fractured surfaces were observed. It was found that mechanical properties were highest when 40% PA powder used in suspension with dip-coating with additional lamination. Fibre failure and fibre pull-out were observed on fractured surfaces.
Effect of Lignin and CNTs on the properties of melt-spun polymeric fibers
Authors: Goulis Panagiotis , Kartsonakis Ioannis A. , Mpalias Konstantinos , Charitidis Costas A.
Published: August 2018

The quality of high density polyethylene (HDPE) - lignin spun fibers depends on the spinning method and the chemical modification of the raw material. On the other hand, nylon-type polymers are widely known for their simple experimental synthesis and use. The goal of this study was the fabrication of composites containing lignin, nylon and multi-walled carbon nanotubes (MWCNTs) based fibers with enhanced mechanical properties. Therefore, a nylon-type polymer was synthesized, using diethylenetriamine and sebacoyl chloride, and was conjugated with lignin as well as MWCNTs with the aim of determining the materials' compatibility, differences in chemical behavior as well as their ability to be melt spun and be further processed. The materials were compounded with HDPE and melt spun, producing fibers that were characterized in respect of their morphology, structural, chemical and elemental composition. Finally, the HDPE fibers were used for the production of one dimensional composites inside dumb bell type sacrificial templates with an epoxy resin solution. The composites, which contained fibers enriched with oxidized lignin and MWCNTs, presented higher elastic modulus and ultimate tensile strength than the rest of the composites. This is a novel attempt, presenting an innovation concerning durable fibers with low cost materials and procedures.
Fatigue design and testing of automotive stabilizer bars
Authors: Giannakis Efstratios , Sivena Elli , Malikoutsakis Michail , Savaidis Georgios
Published: August 2018

Stabilisers are components of the axle suspension system of cars trucks, trains and other moving road vehicles that connect the movement of the two sides of the suspension (right and left) to keep the vehicle levelled. Stabilizers experience bending and torsion at operation. In particular, their arms experience bending while the main body mainly torsional loading. In both cases, the highly stressed area is the surface, where the maximum tensile and shear stresses are acting. High strength steels and special treatments, thermal and/or mechanical, are used for the stabilisers’ manufacturing. The present study deals with necessary input data for fatigue life assessments based on the FKM guideline [1]. In addition, fatigue tests are conducted to calculate the stress-life curves of two different manufacturing processes.
Selective Laser Melting process simulation of open lattice cellular materials
Authors: Lampeas George
Published: August 2018

In the present paper an efficient simulation of an Additive Manufacturing process is presented. The analysis is aiming to quantify the relations between process parameters and material characteristics. The methodology is demonstrated in the fabrication of an open-lattice Body- Centred-Cubic (BCC) cellular core, produced by means of the Additive Manufacturing Selective Laser Melting method. The results of the developed finite element model are compared to experimental results demonstrating a successful validation of the simulation methodology. The results of the present simulation can be used as input for the prediction of the mechanical properties of the cellular materials under investigation.
Comparison of Hertzian and JKR theories with a finite element model in boundary lubrication conditions between a compression ring and a cylinder
Authors: Grigoriadis Kyriakos , Zavos Anastasios , Nikolakopoulos Pantelis G.
Published: August 2018

This study focuses on the creation of an isothermal elastic model to highlight, through stresses, the occurrence of plastic deformation in certain crank angles under extreme dry conditions inside an internal combustion engine. The stresses that are exported from this analysis are pointing out not only the necessity for an elastoplastic model to be created, but also the importance of predicting the correct friction coefficient, as pointed out by both the contact surface stress and those in depth of the two bodies in contact. A comparison between two coefficients of frictions and one frictionless case is conducted. The comparison between the finite element model and the adhesion mathematical model of Johnson, Kendall and Roberts (JKR), seals the importance of the interaction forces, acting on the common solid surface, in the pursuit of defining a propriate contact patch. Furthermore, a three-dimensional model is proposed for further investigation, highlighting the importance of modelling surface’s micro asperities for a solid stress analysis.
Failure analysis of performance vehicle mechanical gear
Authors: Tsolakis Antonios D. , Giannakopoulos Konstantinos I. , Gkertsos Andreas S.
Published: August 2018

Gears are the main machine element in vehicle power transmission trains. In commercial vehicles, power transmission trains design complexity consists of the determination of the loading parameters which depends upon the working environment of the performance vehicle. In the present work a gear failure under dynamic loading is investigated. The failed gear is part of a 2 speed gearbox of a Rotax DD2 2-stroke Open- Wheel performance vehicle (go-cart type). The gearbox was in racing conditions when failure occurred. The vehicle was speeding in 2nd Gear at wide open throttle when instantaneously the driver by fault downshifted to 1st gear. The result was for the first gears break a whole piece and eventually the system to go out of operation. Chemical composition of the examined metallic components was determined via EDAX chemical analysis.
Condition monitoring for the quadruple water tank system using H-infinity Kalman Filtering
Authors: Rigatos Gerasimos , Serpanos Dimitrios , Siadimas Vasilios , Busawon Krishna , Gao Zhiwei , Siano Pierluigi , Abbaszadeh Masoud
Published: August 2018

The problem of statistical fault diagnosis for the quadruple watertanks system is examined. The solution of the fault diagnosis problem for the dynamic model of the four-water tanks system is a non-trivial case, due to nonlinearities and the system’s multivariable structure. In the article’s approach, the system’s dynamic model undergoes first approximate linearization around a temporary operating point which is recomputed at each sampling period. The linearization procedure relies on Taylor series expansion and on the computation of the Jacobian matrices of the state-space description of the system. The H-infinity Kalman Filter is used as a robust state estimator for the approximately linearized model of the quadruple water tanks system. By comparing the outputs of the H-infinity Kalman Filter against the outputs measured from the real water tanks system the residuals sequence is generated. It is concluded that the sum of the squares of the residuals’ vectors, being weighted by the inverse of the associated covariance matrix, stands for a stochastic variable that follows the χ2 distribution. As a consequence, a statistical method for condition monitoring of the quadruple water tanks system is drawn, by using the properties of the χ2 distribution and the related confidence intervals. Actually, normal functioning can be ensured as long as the value of the aforementioned stochastic variable stays within the previously noted confidence intervals. On the other side, one can infer the malfunctioning of the quadruple water tanks system with a high level of certainty (e.g. of the order of 96% to 98%), when these confidence intervals are exceeded. The article’s method allows also for fault isolation, that is for identifying the specific component of the quadruple water tanks system that has been subject to fault or cyber-attack.
Kinderspiel
Authors: Nehrig Ulrike , Piron Laura
Published: August 2018

Pro Jahr verunglücken in Deutschland zwei Millionen Kinder und Jugendliche. Neben Kontusionen und Distorsionen tragen die jungen Patienten häufig Frakturen
davon. Diese unterscheiden sich teils deutlich von denen Erwachsener – im Pathomechanismus und der Nachbehandlung.
Plasma Proteolytic Cascade Activation during Neonatal Cardiopulmonary Bypass Surgery
Authors: Maroney Susan , Peterson Julie , Zwifelhofer Wes , Martinez Nicholas , Yan Ke , Bercovitz Rachel , Woods Ronald , Mast Alan
Published: August 2018

Background Neonates undergoing cardiopulmonary bypass (CPB) surgery to correct congenital heart defects often experience excessive bleeding. Exposure of blood to artificial materials during CPB may activate coagulation, complement and inflammatory pathways. In addition, the surgical stress placed on the haemostatic system may result in cross-activation of other plasma proteolytic cascades, which could further complicate physiological responses to the surgical procedure and post-operative recovery. Plasma protease inhibitors undergo distinct conformational changes upon interaction with proteases, and, thereby, can serve as endogenous biosensors to identify activation of the different proteolytic cascades. We tested the hypothesis that changes in the concentration and conformation of protease inhibitors regulating plasma proteolytic cascades during neonatal CPB are associated with post-operative bleeding.

Patients and Methods Plasma samples from 44 neonates were obtained at four time points across the surgical procedure. Anti-thrombin, antitrypsin, anti-chymotrypsin, anti-plasmin, C1-inhibitor and tissue factor pathway inhibitor (TFPI) concentrations and conformations were evaluated by enzyme-linked immunosorbent assay, transverse urea gradient gel electrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Results/Conclusion The most striking changes were observed following heparin administration and were associated with the appearance of inactive forms of anti-thrombin and an increase in the plasma concentration of TFPI. Changes in anti-thrombin and TFPI remained evident throughout surgery and into the post-operative period but were not different between patients with or without post-operative bleeding. The concentration of antitrypsin decreased across surgery, but there was no significant accumulation of inactive conformations of any inhibitor besides anti-thrombin, indicating that widespread cross-activation of other plasma proteolytic cascades by coagulation proteases did not occur.
Pathophysiology and Imaging Diagnosis of Acute Mesenteric Ischemia
Authors: Sandstrom Claire
Published: August 2018

Acute mesenteric ischemia is a potentially life-threatening condition associated with high mortality, particularly with any delay in treatment. Prompt diagnosis with imaging is crucial to achieve a favorable outcome. Both arterial and venous etiologies can result in ischemia, and the radiologist plays a central role in the initial evaluation of a patient with suspected acute mesenteric ischemia to guide management decisions. This article will review the appropriate imaging evaluation of a patient with suspected acute mesenteric ischemia. The overlapping and the distinguishing findings on imaging, as well as the relevant clinical features, will be discussed for the spectrum of both common and uncommon etiologies of mesenteric ischemia.
Development of geothermal heat pumps by using environment friendly refrigerants
Authors: Saeidi Vahid , Mafi Mostafa , Mohammadi Ali
Published: August 2018

Today, energy consumption and demand together with global warming are one of the most important challenges of human life. From the environmental point of view, the Heating Ventilation and Air Conditioning industry and current refrigerants are one of the important factors of global warming which need to be resolved. In terms of energy consumption, the main way is the development and use of renewable energy technologies which not only increases the efficiency of these systems but also generates diversification in energy resources. Among the various renewable energy systems, geothermal heat pumps offer significant potential to reduce energy consumption and also carbon dioxide emissions. The main purpose of this research is to select environmentally friendly refrigerants with the best performances. To assess the thermodynamic performance of organic refrigerants in geothermal heat pumps, this system is modeled using Engineering Equation Solver software. In this research, the results are compared with the results of the thermodynamic behavior of conventional refrigerants R22 and R134a for geothermal heat pumps with horizontal and vertical closed loop ground heat exchangers and also open-loop systems. Finally, R152a, R600, and R717 were introduced as substitute refrigerants to replace with synthetic refrigerants in the above-mentioned geothermal heat pump systems, resulted in an increase in 2.97–5.8 percent coefficient of performance in the cooling mode which means reducing the operating cost of the system compared to conventional artificial refrigerants.
Relaxation of long-lived modes in NMR of deuterated methyl groups
Authors: Ivanov Konstantin L. , Kress Thomas , Baudin Mathieu , Guarin David , Abergel Daniel , Bodenhausen Geoffrey , Kurzbach Dennis
Published: August 2018

Long-lived imbalances of spin state populations can circumvent fast quadrupolar relaxation by reducing effective longitudinal relaxation rates by about an order of magnitude. This opens new avenues for the study of dynamic processes in deuterated molecules. Here we present an analysis of the relaxation properties of deuterated methyl groups CD3. The number of coupled equations that describe cross-relaxation between the 27 symmetry-adapted spin states of a D3 system can be reduced to only 2 non-trivial “lumped modes” by (i) taking the sums of the populations of all states that equilibrate rapidly within each irreducible representation of the symmetry group, and (ii) by combining populations that have similar relaxation rates although they belong to different irreducible representations. The quadrupolar relaxation rates of the spin state imbalances in CD3 groups are determined not by the correlation time of overall tumbling of the molecule, but by the frequency of jumps of methyl groups about their three-fold symmetry axis. We access these states via dissolution dynamic nuclear polarization (D-DNP), a method that allows one to populate the desired long-lived states at cryogenic temperatures and their subsequent detection at ambient temperatures after rapid dissolution. Experimental examples of DMSO-d6 and ethanol-d6 demonstrate that long-lived deuterium spin states are indeed accessible and that their lifetimes can be determined. Our analysis of the system via “lumped” modes allows us to visualize different possible spin-state populations of symmetry A, B, or E. Thus, we identify a long-lived spin state involving all three deuterons in a CD3 group as an A/E imbalance that can be populated through DNP at low temperatures.
Enhanced photon-extraction efficiency from InGaAs/GaAs quantum dots in deterministic photonic structures at 1.3 μm fabricated by in-situ electron-beam lithography
Authors: Srocka N. , Musiał A. , Schneider P.-I. , Mrowiński P. , Holewa P. , Burger S. , Quandt D. , Strittmatter A. , Rodt S. , Reitzenstein S. , Sęk G.
Published: August 2018

The main challenge in the development of non-classical light sources remains their brightness that limits the data transmission and processing rates as well as the realization of practical devices operating in the telecommunication range. To overcome this issue, we propose to utilize universal and flexible in-situ electron-beam lithography and hereby, we demonstrate a successful technology transfer to telecom wavelengths. As an example, we fabricate and characterize especially designed photonic structures with strain-engineered single InGaAs/GaAs quantum dots that are deterministically integrated into disc-shaped mesas. Utilizing this approach, an extraction efficiency into free-space (within a numerical aperture of 0.4) of (10±2) % has been experimentally obtained in the 1.3 μm wavelength range in agreement with finite-element method calculations. High-purity single-photon emission with g(2)(0)<0.01 from such deterministic structure has been demonstrated under quasi-resonant excitation.
Effects of simulated seedling defoliation on growth and yield of cotton in southern New South Wales
Authors: Mo Jianhua , McDougall Sandra , Beaumont Sarah , Munro Scott , Stevens Mark M.
Published: August 2018

Early-season leaf loss due to damage by thrips (Thysanoptera: Thripidae) is considered an important issue by Australian cotton growers. To understand the potential impact of early-season leaf loss in the southern region of New South Wales, we investigated the effects of artificial defoliation on cotton growth, maturity timing and lint yield over four seasons (2013–14 to 2016–17) in commercial cotton crops in the Riverina district. Four defoliation scenarios were investigated: (i) complete defoliation, 100% removal of all true leaves from all plants; (ii) partial defoliation by plant, 100% removal of all true leaves from 75% of plants; (iii) partial defoliation by leaf, removal of 75% of leaf area from all individual true leaves on all plants; and (iv) no defoliation. Defoliation was done by hand at the onset of the 2-, 4-, and 6-node growth stages. Defoliated plants were initially shorter than undefoliated (control) plants, but by ~100-days post seedling emergence, height differences were no longer statistically significant in two of the four seasons. Defoliation did not affect the total number of bolls shortly before harvest. However, complete defoliation delayed crop maturity by up to 18 days and partial defoliation by plant delayed crop maturity by up to 8 days. Because of the delays, fully defoliated plants often had fewer open bolls shortly before harvest and yielded significantly less than undefoliated plants in three of the four seasons. A laboratory experiment with caged cotton seedlings showed that weekly introductions of up to10 thrips per seedling (predominantly onion thrips (Thrips tabaci), the most abundant species on cotton in the region) caused significant clubbing in true leaves, but the total leaf area was not significantly reduced at the 6-node stage. Implications of the results for southern cotton integrated pest management are discussed.
New thermophilic prokaryotes with hydrolytic activities
Authors: Bonch-Osmolovskaya Elizaveta , Elcheninov Alexander , Zayulina Ksenia , Kublanov Ilya
Published: August 2018

Thermophilic microorganisms are capable of growing on polymeric substrates and have been intensively studied for their enzymes, thermostable hydrolases (glycosidases, proteinases, lipases), which have important applications in many fields of bioindustry: production of detergents, food processing, paper and textile industry, biofuel formation from organic wastes, etc.1. The advantages of thermostable enzymes application are in their higher stability not only against temperature, but also against high or low pH, presence of detergents, etc. High temperature increases solubility of substrates2, thus making them more available, and significantly decreases the contamination risks. Many highly stable hydrolases, produced by thermophilic bacteria and archaea have been discovered3–6; however, due to continuous industrial demand and our knowledge that natural environments are a significant reservoir of genetic and hence functional diversity7, new thermophilic organisms producing hydrolytic enzymes are still of high interest. Here we present our achievements in isolation of novel thermophilic bacteria and archaea with various hydrolytic activities.
The role of non-spore-forming actinobacteria in cleaning up sites contaminated by persistent pollutants and the ability of these microorganisms to survive under unfavourable conditions
Authors: Solyanikova Inna P , Suzina Natalia E , Golovleva Ludmila A
Published: August 2018

Years of research has shown that actinobacteria, including Rhodococcus, Gordonia, Arthrobacter, Microbacteria, play an important role in cleaning up sites contaminated by persistent organic pollutants. Under special conditions, actinobacteria of different genera are able to form specific forms, cyst-like resting cells (CLC), which maintain the viability during long-term storage (for at least 5–6 years, our unpublished results). These cells quickly germinate when conditions become favourable for growth. As a result, actinobacteria can be used as a basis for creating highly efficient biological preparations for cleaning up the soil with high levels of toxic contaminants such as (chloro)phenols, (chloro)biphenyls, polycyclic hydrocarbons, oil1.
Resource depletion and mechanisms for food web robustness in a Neotropical estuary
Authors: Monteiro Angelo Barbosa , Contente Riguel Feltrin , Faria Lucas Del Bianco
Published: August 2018

Human activities severely threaten biological communities in Neotropical estuaries. Nevertheless, these communities have been poorly studied in comparison to low biodiversity regions, despite the fact that conservation efforts in these habitats are expected to require longer time-scales and greater efforts. In the present study we simulated resource depletion in a consumer–resource food web in a high-diversity Neotropical estuary. We first describe the feeding patters of local assemblages, split across distinct upper and lower estuary habitats. Further, because fish are opportunistic consumers of locally abundant prey, we modelled community robustness using resource availability, number of resources consumed, consumption diversity and environmental constraints. We found different feeding patterns between the upper and lower estuary habitats. Although crustaceans and detritus were preferably consumed in both habitats, thorough identification demonstrated higher dissimilarity between sites of different habitats relative to sites within the same habitat. We found that community robustness has a positive relationship with consumption diversity and that habitat type (upper or lower estuary) was a poor predictor of robustness. However, the modelling results also indicated an interaction between consumption diversity and habitat type. This suggests that promoting spatial gradients across resources, abiotic conditions and local feeding patterns within habitats can help protect against human-mediated disturbances.
Translating Thartharah fawq al-Nil (“Adrift on the Nile”)
Authors: Dowaidar Ibrahim M.
Published: August 2018

Translation is an interdisciplinary activity in which translators must consider all aspects of the text being translated, including both psychology and ideology. They must also view translation as a complex process that spans linguistic, cultural, economic, and ideological factors, analysing intricate issues that usually lie at the boundaries of languages, cultures, and societies. This paper examines the challenges inherent in translating the sociolinguistic aspects of Thartharah fawq al-Nil (1966), published in English as “Adrift on the Nile” (1993) – challenges that include drug addicts’ slang and jargon, register, and figurative language. The specific objective is to identify error patterns produced by the translator and to analyse these errors quantitatively and qualitatively, assessing their negative impact on the reader and suggesting possible solutions. “Adrift on the Nile” is an important novel in an exceptional period of modern Egyptian history, and is regarded by many critics as “one of the richest essays on symbolism” (Allen 1982: 145). This paper calls for adopting a more sociolinguistic perspective when translating unique texts overloaded with cultural and socio-political meanings.
Large extracellular vesicles carry most of the tumour DNA circulating in prostate cancer patient plasma
Authors: Vagner Tatyana , Spinelli Cristiana , Minciacchi Valentina R. , Balaj Leonora , Zandian Mandana , Conley Andrew , Zijlstra Andries , Freeman Michael R. , Demichelis Francesca , De Subhajyoti , Posadas Edwin M. , Tanaka Hisashi , Di Vizio Dolores
Published: August 2018

Cancer‐derived extracellular vesicles (EVs) are membrane‐enclosed structures of highly variable size. EVs contain a myriad of substances (proteins, lipid, RNA, DNA) that provide a reservoir of circulating molecules, thus offering a good source of biomarkers. We demonstrate here that large EVs (L‐EV) (large oncosomes) isolated from prostate cancer (PCa) cells and patient plasma are an EV population that is enriched in chromosomal DNA, including large fragments up to 2 million base pair long. While L‐EVs and small EVs (S‐EV) (exosomes) isolated from the same cells contained similar amounts of protein, the DNA was more abundant in L‐EVs, despite S‐EVs being more numerous. Consistent with in vitro observations, the abundance of DNA in L‐EV obtained from PCa patient plasma was variable but frequently high. Conversely, negligible amounts of DNA were present in the S‐EVs from the same patients. Controlled experimental conditions, with spike‐ins of L‐EVs and S‐EVs from cancer cells in human plasma from healthy subjects, showed that circulating DNA is almost exclusively enclosed in L‐EVs. Whole genome sequencing revealed that the DNA in L‐EVs reflects genetic aberrations of the cell of origin, including copy number variations of genes frequently altered in metastatic PCa (i.e. MYC, AKT1, PTK2, KLF10 and PTEN). These results demonstrate that L‐EV‐derived DNA reflects the genomic make‐up of the tumour of origin. They also support the conclusion that L‐EVs are the fraction of plasma EVs with DNA content that should be interrogated for tumour‐derived genomic alterations.
A novel microtubule nucleation pathway for meiotic spindle assembly in oocytes
Authors: Romé Pierre , Ohkura Hiroyuki
Published: August 2018

The meiotic spindle in oocytes is assembled in the absence of centrosomes, the major microtubule nucleation sites in mitotic and male meiotic cells. A crucial, yet unresolved question in meiosis is how spindle microtubules are generated without centrosomes and only around chromosomes in the exceptionally large volume of oocytes. Here we report a novel oocyte-specific microtubule nucleation pathway that is essential for assembling most spindle microtubules complementarily with the Augmin pathway. This pathway is mediated by the kinesin-6 Subito/MKlp2, which recruits the γ-tubulin complex to the spindle equator to nucleate microtubules in Drosophila oocytes. Away from chromosomes, Subito interaction with the γ-tubulin complex is suppressed by its N-terminal region to prevent ectopic microtubule assembly in oocytes. We further demonstrate in vitro that the Subito complex from ovaries can nucleate microtubules from pure tubulin dimers. Collectively, microtubule nucleation regulated by Subito drives spatially restricted spindle assembly in oocytes.
Draft genome assembly of the invasive cane toad, Rhinella marina
Authors: Edwards Richard J , Tuipulotu Daniel Enosi , Amos Timothy G , O'Meally Denis , Richardson Mark F , Russell Tonia L , Vallinoto Marcelo , Carneiro Miguel , Ferrand Nuno , Wilkins Marc R , Sequeira Fernando , Rollins Lee A , Holmes Edward C , Shine Richard , White Peter A
Published: August 2018

Background

The cane toad (Rhinella marina formerly Bufo marinus) is a species native to Central and South America that has spread across many regions of the globe. Cane toads are known for their rapid adaptation and deleterious impacts on native fauna in invaded regions. However, despite an iconic status, there are major gaps in our understanding of cane toad genetics. The availability of a genome would help to close these gaps and accelerate cane toad research.

Findings

We report a draft genome assembly for R. marina, the first of its kind for the Bufonidae family. We used a combination of long-read Pacific Biosciences RS II and short-read Illumina HiSeq X sequencing to generate 359.5 Gb of raw sequence data. The final hybrid assembly of 31,392 scaffolds was 2.55 Gb in length with a scaffold N50 of 168 kb. BUSCO analysis revealed that the assembly included full length or partial fragments of 90.6% of tetrapod universal single-copy orthologs (n = 3950), illustrating that the gene-containing regions have been well assembled. Annotation predicted 25,846 protein coding genes with similarity to known proteins in Swiss-Prot. Repeat sequences were estimated to account for 63.9% of the assembly.

Conclusions

The R. marina draft genome assembly will be an invaluable resource that can be used to further probe the biology of this invasive species. Future analysis of the genome will provide insights into cane toad evolution and enrich our understanding of their interplay with the ecosystem at large.
Cost-effectiveness of a mentorship and quality improvement intervention to enhance the quality of antenatal care at rural health centers in Rwanda
Authors: Manzi Anatole , Mugunga Jean Claude , Nyirazinyoye Laetitia , Iyer Hari S , Hedt-Gauthier Bethany , Hirschhorn Lisa R , Ntaganira Joseph
Published: August 2018

Objective

To estimate cost-effectiveness of Mentorship, Enhanced Supervision for Healthcare and Quality Improvement (MESH-QI) intervention to strengthen the quality of antenatal care at rural health centers in rural Rwanda.

Design

Cost-effectiveness analysis of the MESH-QI intervention using the provider perspective.

Setting

Kirehe and Rwinkwavu District Hospital catchment areas, Rwanda.

Intervention

MESH-QI.

Main outcome measures

Incremental cost per antenatal care visit with complete danger sign and vital sign assessments.

Results

The total annual costs of standard antenatal care supervision was 10 777.21 USD at the baseline, whereas the total costs of MESH-QI intervention was 19 656.53 USD. Human resources (salary and benefits) and transport drove the majority of program expenses, (44.8% and 40%, respectively). Other costs included training of mentors (12.9%), data management (6.5%) and equipment (6.5%). The incremental cost per antenatal care visit attributable to MESH-QI with all assessment items completed was 0.70 USD for danger signs and 1.10 USD for vital signs.

Conclusions

MESH-QI could be an affordable and effective intervention to improve the quality of antenatal care at health centers in low-resource settings. Cost savings would increase if MESH-QI mentors were integrated into the existing healthcare systems and deployed to sites with higher volume of antenatal care visits.
Repeat Stereotactic Radiosurgery for Progressive or Recurrent Vestibular Schwannomas
Authors: Iorio-Morin Christian , Liscak Roman , Vladyka Vilibald , Kano Hideyuki , Jacobs Rachel C , Lunsford L Dade , Cohen-Inbar Or , Sheehan Jason , Emad Reem , Karim Khalid Abdel , El-Shehaby Amr , Reda Wael A , Lee Cheng-Chia , Pai Fu-Yuan , Wolf Amparo , Kondziolka Douglas , Grills Inga , Lee Kuei C , Mathieu David
Published: August 2018

BACKGROUND

Stereotactic radiosurgery (SRS) is a highly effective management approach for patients with vestibular schwannomas (VS), with 10-yr control rates up 98%. When it fails, however, few data are available to guide management.

OBJECTIVE

To perform a retrospective analysis of patients who underwent 2 SRS procedures on the same VS to assess the safety and efficacy of this practice.

METHODS

This study was opened to centers of the International Gamma Knife Research Foundation (IGKRF). Data collected included patient characteristics, clinical symptoms at the time of SRS, radiosurgery dosimetric data, imaging response, clinical evolution, and survival. Actuarial analyses of tumor responses were performed.

RESULTS

Seventy-six patients from 8 IGKRF centers were identified. Median follow-up from the second SRS was 51.7 mo. Progression after the first SRS occurred at a median of 43 mo. Repeat SRS was performed using a median dose of 12 Gy. Actuarial tumor control rates at 2, 5, and 10 yr following the second SRS were 98.6%, 92.2%, and 92.2%, respectively. Useful hearing was present in 30%, 8%, and 5% of patients at first SRS, second SRS, and last follow-up, respectively. Seventy-five percent of patients reported stable or improved symptoms following the second SRS. Worsening of facial nerve function attributable to SRS occurred in 7% of cases. There were no reports of radionecrosis, radiation-associated edema requiring corticosteroids, radiation-related neoplasia, or death attributable to the repeat SRS procedure.

CONCLUSION

Patients with progressing VS after radiosurgery can be safely and effectively managed using a second SRS procedure.
Opportunities and challenges of incorporating clinical outcome assessments in brain tumor clinical trials
Authors: Molinari Emanuela , Mendoza Tito R , Gilbert Mark R
Published: August 2018

Regulatory agencies have progressively emphasized the importance of assessing broader aspects of patient well-being to better define therapeutic gain. As a result, clinical outcome assessments (COAs) are increasingly used to evaluate the impact, both positive and negative, of cancer treatments and in some instances have played a major factor in the regulatory approval of drugs. Challenges remain, however, in the routine incorporation of these measures in cancer clinical trials, particularly in brain tumor studies. Factors unique to brain tumor patients such as cognitive decline and language dysfunction may hamper their successful implementation. Study designs often relegated these outcome measures to exploratory endpoints, further compromising data completion. New strategies are needed to maximize the complementary information that COAs could add to clinical trials alongside more traditional measures such as progression-free and overall survival. The routine incorporation of COAs as either primary or secondary objectives with attention to minimizing missing data should define a novel clinical trial design. We provide a review of the approaches, challenges, and opportunities for incorporating COAs into brain tumor clinical research, providing a perspective for integrating these measures into clinical trials.
Lumbar Arthroplasty Core Herniation Presenting With Cauda Equina Syndrome: Case Report of a Rare Complication
Authors: Elswick Clay M , Ahmed Hazem M
Published: August 2018

BACKGROUND

Treatment failures of artificial disc implantation are well-described, but posterior herniation of the arthroplasty core is rare. We present a case of posterior herniation of the arthroplasty core resulting in cauda equina syndrome in a 36-yr-old woman. Preoperative imaging studies including computed tomography (CT), magnetic resonance imaging (MRI), and CT Myelogram were performed; only the CT Myelogram demonstrated the severe compression well. This report highlights the radiographic findings on multiple imaging modalities, clinical implications, and management considerations of posterior arthroplasty failures.

OBJECTIVE

To demonstrate a rare complication of lumbar arthroplasties. The biomechanical considerations, surgical management, and thorough radiographic work-up demonstrate successful diagnosis and treatment of this unusual complication.

METHODS

The patient's chart was reviewed for medical history, laboratory and radiographic studies, and outpatient clinical follow-up.

RESULTS

After imaging work-up, this patient was found to have a herniation of the arthroplasty core at L5-S1. She was taken emergently to the operating room for a decompression at L5-S1 and arthroplasty core removal. She made some recovery neurological, but over 3 mo time, she developed a spondylolisthesis with new back pain and radiculopathy. This ultimately responded well to an L5-S1 instrumented posterior fusion.

CONCLUSION

Posterior herniation of the lumbar arthroplasty core is a rare complication from implantation of an artificial lumbar disc. Confirmation of the diagnosis is best confirmed with a CT Myelogram. Furthermore, this case underscores the biomechanical importance of the artificial disc given the development of the spondylolisthesis after removal, and fusion after arthroplasty core removal should be considered.
The Zurich Checklist for Safety in the Intraoperative Magnetic Resonance Imaging Suite: Technical Note
Authors: Stienen Martin N , Fierstra Jorn , Pangalu Athina , Regli Luca , Bozinov Oliver
Published: August 2018

BACKGROUND

Recently, the use of intraoperative magnetic resonance imaging (ioMRI) has evolved in neurosurgery. Challenges related to ioMRI-augmented procedures are significant, since the magnetic field creates a potentially hazardous environment. Strict safety guidelines in the operating room (OR) are necessary. Checklists can minimize errors while increasing efficiency and improving workflow.

OBJECTIVE

To describe the Zurich checklists for safety in the ioMRI environment.

METHODS

We summarize the checklist protocol and the experience gained from over 300 surgical procedures performed over a 4-yr period using this new system for transcranial or transsphenoidal surgery in a 2-room high-field 3 Tesla ioMRI suite.

RESULTS

Particularities of the 2-room setting used at our institution can be summarized as (1) patient transfer from a sterile to a nonsterile environment and (2) patient transfer from a zone without to a zone with a high-strength magnetic field. Steps on the checklist have been introduced for reasons of efficient workflow, safety pertaining to the strength of the magnetic field, or sterility concerns. Each step in the checklist corresponds to a specific phase and particular actions taken during the workflow in the ioMRI suite. Most steps are relevant to any 2-room ioMRI-OR suite.

CONCLUSION

The use of an ioMRI-checklist promotes a zero-tolerance attitude for errors, can lower complications, and can help create an environment that is both efficient and safe for the patient and the OR personnel. We highly recommend the use of a surgical checklist when applying ioMRI.
Prompts to increase physical activity at points-of-choice between stairs and escalators: what about escalator climbers?
Authors: Bellettiere John , Nguyen Ben , Liles Sandy , Berardi Vincent , Adams Marc A , Dempsey Paddy , Benporat Yael , Kerr Jacqueline , LaCroix Andrea Z , Hovell Melbourne
Published: August 2018

Since 1980, many studies have evaluated whether stair-use prompts increased physical activity by quantifying changes in stair use. To more completely evaluate changes in physical activity, this study addressed the often-overlooked assessment of climbing up escalators by evaluating the degree to which stair-use sign prompts increased active ascent—defined as stair use or escalator climbing. Over 5 months, at an airport stairs/escalator point of choice, we video-recorded passersby (N = 13,544) who ascended either stairs or escalators, on 10 days with signs and 10 days without signs. Ascenders using the stairs, standing on the escalator, and climbing the escalator were compared on days with versus without signs using multivariable logistic regression. The percentage of ascenders on days with versus without signs were as follows: stair use, 6.9 versus 3.6 percent; escalator standing, 75.2 versus 76.0 percent; and escalator climbing, 18.5 versus 20.4 percent. Signs more than doubled the odds of stair use (vs. escalator use; OR = 2.25; 95% CI = 1.90–2.68; p < .001). Signs decreased the odds of escalator climbing (vs. escalator standing or stair use); OR = 0.90; 95% CI = 0.82−0.99; p = .028). Signs increased the odds of active ascent versus escalator standing by 15 percent (OR = 1.15; 95% CI = 1.05–1.25; p = .002). Although stair-use prompts increased stair use more than twofold (125%), they increased active ascent by only 15 percent, partly because escalator climbing—a behavior not targeted by the intervention—decreased. Although our results corroborated the established consensus that point-of-choice prompts increase stair use, future studies should test interventions designed to increase active ascent.
Gender differences in utilization of services and tobacco cessation outcomes at a state quitline
Authors: Allen Alicia M , Yuan Nicole P , Wertheim Betsy C , Krupski Laurie , Bell Melanie L , Nair Uma
Published: August 2018

Research suggests that women may have poorer tobacco cessation outcomes than men; however, the literature is somewhat mixed. Less is known about gender differences in cessation within quitline settings. This study examined gender differences in the utilization of services (i.e., coaching sessions, pharmacotherapy) and tobacco cessation among callers to the Arizona Smokers’ Helpline (ASHLine). The study sample included callers enrolled in ASHLine between January 2011 and June 2016. We tracked number of completed coaching sessions. At the 7-month follow-up, callers retrospectively reported use of cessation pharmacotherapy (gum, patch, or lozenge), as well as current tobacco use. Associations between gender and tobacco cessation were tested using logistic regression models. At month 7, 36.4% of women (3,277/9,004) and 40.3% of men (2,960/7,341) self-reported 30-day point prevalence abstinence. Compared to men, fewer women reported using pharmacotherapy (women: 71.4% vs. men: 73.6%, p = .01) and completed at least five coaching sessions (women: 35.1% vs. men: 38.5%, p < .01). After adjusting for baseline characteristics, women had significantly lower odds of reporting tobacco cessation than men (OR = 0.91, 95% CI: 0.84 to 0.99). However, after further adjustment for use of pharmacotherapy and coaching, there was no longer a significant relationship between gender and tobacco cessation (OR: 0.96, 95% CI: 0.87 to 1.06). Fewer women than men reported tobacco cessation. Women also had lower utilization of quitline cessation services. Although the magnitude of these differences were small, future research on improving the utilization of quitline services among women may be worth pursuing given the large-scale effects of tobacco.