bluuebunny/crossref_metadata_2025 huggingface dataset:
Metamaterial-based dual-band microwave absorber with polarization insensitive and wide-angle performance
Authors: Agarwal Mayank , Meshram Manoj Kumar
Published: September 2018

A polarization insensitive, wide angle low profile metamaterial absorber with dual-band absorption characteristics in C- and X-frequency bands is presented in this paper. The parametric variation is discussed in details to understand the dependence of absorption frequency and absorption level on the design parameters. The proposed structure supports the realization of near unity absorption at the two absorption frequencies independently by suitably varying the design parameters. The absorption mechanism is explained with the E-field and surface current distribution plots at the peak absorption frequencies. The absorption is due to the simultaneous excitation of electric and magnetic resonance in the structure. Constitutive electromagnetic parameters of the proposed structure are also retrieved and plotted against frequency. A sample of the proposed absorber is fabricated and measured response validates the numerical results.
Strange nonchaotic and chaotic attractors in a self-excited thermoacoustic oscillator subjected to external periodic forcing
Authors: Guan Yu , Murugesan Meenatchidevi , Li Larry K. B.
Published: September 2018

We experimentally investigate the synchronization dynamics of a self-excited thermoacoustic system forced beyond its phase-locked state. The system consists of a laminar premixed flame in a tube combustor subjected to periodic acoustic forcing. On increasing the forcing amplitude above that required for phase locking, we find that the system can transition out of phase locking and into chaos, which is consistent with the Afraimovich–Shilnikov theorem for the breakdown of a phase-locked torus. However, we also find some unexpected behavior, most notably the emergence of a strange nonchaotic attractor (SNA) before the onset of chaos. We verify the existence of the SNA and chaotic attractor by examining the correlation dimension, the autocorrelation function, the power-law scaling in the Fourier amplitude spectrum, the permutation entropy in a pseudoperiodic surrogate test, and the permutation spectrum. In summary, this study explores the SNA and chaotic dynamics of a thermoacoustic system forced beyond its phase-locked state, opening up new pathways for the development of alternative strategies to control self-excited thermoacoustic oscillations in combustion devices such as gas turbines and rocket engines.
Microfluidic approaches for cell-based molecular diagnosis
Authors: Lee Dong Jun , Mai John , Huang Tony Jun
Published: September 2018

The search for next-generation biomarkers has enabled cell-based diagnostics in a number of disciplines ranging from oncology to pharmacogenetics. However, cell-based diagnostics are still far from clinical reality due to the complex assays and associated protocols which typically require cell isolation, lysis, DNA extraction, amplification, and detection steps. Leveraging recent advances in microfluidics, many biochemical assays have been translated onto microfluidic platforms. We have compared and summarized recent advances in modular approaches toward the realization of fully-integrated, cell-based molecular diagnostics for clinical and point-of-care applications.
A fully soft generator with embedded conditioning circuitry
Authors: Wang Yongquan , Zhu Liangquan , Zhang Gong , Chen Hualing
Published: September 2018

This letter presents a fully soft dielectric elastomer generator (DEG) based on a capacitive kinetic-energy-harvesting mechanism. First, using the principle of a passive charge pump, a self-cycling conditioning circuit topology is proposed. Through the electrical reciprocity of a cyclically deforming DEG and another capacitor in series with it, the generated charge can be continuously supplied to the load, via a bilateral conditioning bridge. The antagonistic dual-DEG scheme not only produces a larger potential to drive more charge in the flow but also provides a basic solution to soften the whole device. A further measure is to replace the bridge diodes with special dielectric elastic switches (DESs), which can be embedded into the DEG and synchronously deformed with the latter to control the on/off state of the circuit branches. The intrinsic physical mechanism and characteristics of the change in the resistance of the DES as a function of stretch and electric fields are investigated. We tested and compared the diode-bridge and DES-bridge schemes under different electrical loads and tensile strokes. The results indicate that under certain conditions, the DES-bridge circuit can achieve comparable performance with that of a conventional scheme, which suggests that a fully soft DEG system is possible. We experimentally evaluated and discussed its reliability in practice.
Modeling of thermal runaway of carbonaceous materials: Graphite, biochar, and wood
Authors: Muñoz-Hernández Andrés , Diaz Gerardo
Published: September 2018

Joule heating is an important mechanism in electronic devices. It must be carefully controlled to avoid the possibility of thermal runaway, which can happen in a fraction of a second. In contrast, there are some applications in which reaching high temperatures in such short times would be desired, such as in biomass gasification systems. In this paper, a transient one-dimensional model based on the energy equation coupled with the charge conservation and voltage equations is used to analyze thermal runaway for various carbonaceous materials ranging from wood, which is an electrical insulator, to biochar, which is a moderate electrical conductor, to graphite which has high electrical conductivity. Numerical results are obtained for the temporal evolution of the temperature and charge distribution, as well as, Joule heating, heat losses, electric field, and voltage. It is found that for higher applied voltages the charges accumulate mostly near the boundaries, and due to the increase of the electrical conductivity with temperature, the dynamics of thermal runaway are observed. In addition, a nondimensional analysis is performed to determine the operating conditions that generate significant Joule heating in relation to heat losses. The dimensionless time, Fo, to reach a prescribed maximum lattice temperature is calculated given a set of bias conditions and dimensions in the form of a nondimensional parameter M2.
System level design of the ITER bolometer port plug cameras
Authors: Penzel F. , Meister H. , Hermann D. , Pataki A. , Walcz E. , Nadasi G. , Szabo-Balint Z. , Tatar L. , Walach U. , Ingesson L. C. , Reichle R. , Sanchez J.
Published: September 2018

The ITER bolometer diagnostic is planned to have 550 lines of sight (LOS) distributed all over the vessel. 240 channels are provided by cameras mounted in two upper ports and in one equatorial port. This paper describes the current status of the system level design of the port cameras and the solutions proposed on how to implement all required camera components while meeting a multitude of competing requirements. Sensor holders, support structures, and different apertures depending on the camera type (pinhole or collimator), cable connectors, ceramic track plates, and many mineral insulated cables have to be integrated within a restricted space envelope to guarantee functionality. The design of the internal electrical interfaces and the external mechanical mountings will be described as well. Using the example of an upper port camera with 60 LOS, the assembly of the camera components is explained and two currently discussed architecture options for the remote handling maintenance scheme in the hot cell are compared.
Laser-driven hydrothermal wave speed in low-Z foam of overcritical density
Authors: Cipriani M. , Gus'kov S. Yu. , De Angelis R. , Consoli F. , Rupasov A. A. , Andreoli P. , Cristofari G. , Di Giorgio G.
Published: September 2018

The speed of the laser-supported hydrothermal wave is experimentally measured in porous polystyrene with overcritical average density. The results of the experiments are in agreement with the simulations performed with the MULTI-FM code, modeling the state of partly homogenized plasma. The measured velocity is 2 times smaller than the shock wave velocity calculated in simulations under the same conditions of laser irradiation in a homogeneous substance of the same density. The obtained results allow us to better investigate the possibility of using porous matter of overcritical density as an effective absorber-ablator in laser thermonuclear fusion targets.
Electron cyclotron resonance plasma excitation in a toroidal plasma
Authors: Yu Y. , Xu M. , Wang H. J. , Wen Y. Z. , Lan T. , Liu Z. , Gong S. B. , Yuan B. D. , Wu Y. F. , Ye M. Y. , Duan X. R.
Published: September 2018

In this article, Electron Cyclotron Resonance (ECR) absorption, Upper-Hybrid Resonance (UHR) absorption and Electron Bernstein Wave (EBW) conversion are systematically confirmed in magnetically confined KT-5D plasma which is sole-excited by a magnetron source. A 2.45 GHz ECR system has been developed on the toroidal helimak KT-5D to produce and sustain a steady-state plasma. 0.98 kW electron cyclotron wave produced by the magnetron is injected into the vacuum chamber through rectangular waveguides with a power absorption efficiency of 40∼50%. A steady-state plasma is excited with a density of several 1016/m3 and electron temperature of up to 30 eV. The radial profile of plasma density shows that ECR absorption dominates the power deposition with a higher hydrogen pressure of at the order of 10-1 Pa, while UHR absorption dominates with a lower hydrogen pressure of at the order of 10-2 Pa. Plasma density in the discharge with a superimposed magnetic shear has demonstrated the wave conversion from ECR to EBW.
Modeling polymer extrusion with varying die gap using Arbitrary Lagrangian Eulerian (ALE) method
Authors: Toukhtarian Raffi , Hatzikiriakos Savvas G. , Atsbha Haile , Boulet Benoit
Published: September 2018

A transient arbitrary Lagrangian Eulerian based finite element method is used to simulate the effects of varying the die gap during the extrusion of Newtonian fluids. The transient change of the extrudate shape, velocity, and pressure due to the die gap variation is described and studied. Moreover, varying the die gap creates oscillations on the simulated free surface of the extrudate at higher Reynolds number values thus requiring a finer mesh. A new method for defining the free surface is introduced to avoid free surface oscillations. The new method enables the use of a coarse mesh which makes it possible to run simulations with shorter computational time at higher Reynolds numbers.
Liquid film flow over an unsteady moving surface with a new stretching velocity
Authors: Fang Tiegang , Wang Fujun , Gao Bo
Published: September 2018

In this paper, the liquid film flow over an unsteady moving surface is investigated by considering a new surface moving velocity Uw = Ax/t. With this prescribed surface velocity, the governing Navier-Stokes (NS) equations are transformed into a similarity ordinary differential equation, which is solved numerically for both two-dimensional and axisymmetric flow configurations. The results are an exact solution to the full NS equations. The flow characteristics are controlled by a wall moving parameter, namely, A. It is found that solutions only exist for a certain range of the wall moving parameter, i.e., A ≥ −1/2 for the two dimensional case and A ≥ −1/4 for the axisymmetric case. The dimensionless liquid film thickness (β) first increases with the increase in A in the solution domain, and then, it reaches a peak of βm = 1.3864 at A = 0.90 for the two-dimensional case and βm = 1.5836 at A = 0.53 for the axisymmetric case. For both flow configurations, the liquid film thickness increases with time and there exists flow reversal for a positive value of A. These new solutions can not only provide an exact solution to the NS equations but also be used to explain the liquid film flow occurring in practical applications.
Direct observation of the domain kinetics during polarization reversal of tetragonal PMN-PT crystal
Authors: Ushakov A. D. , Esin A. A. , Akhmatkhanov A. R. , Hu Q. , Liu X. , Zhao Y. , Wei X. , Shur V. Ya.
Published: September 2018

Lead magnesium niobate-lead titanate (PMN-PT) solid solutions are intensively studied for the last two decades due to their outstanding piezoelectric properties. However, despite the strong interest, there is a lack of studies of domain kinetics and domain structure evolution, which are of great importance for the development of domain engineering in PMN-PT. We present the results of the domain kinetics study during polarization reversal in tetragonal PMN-PT single crystals by in situ optical visualization accompanied by analysis of the switching current. Three types of domain structure evolution have been revealed: (1) formation and growth of macroscopic a-domains, (2) formation of charged domain walls as a result of intersections of macroscopic a-domains, and (3) formation and growth of c-domains. The domain wall motion velocities were estimated. It has been shown by comparison of the switching current and optical one that the main switching current peak is related to the growth of c-domains, whereas the small one is caused by the capacitive input of the charged domain walls. The enhancement of dielectric permittivity by two orders of magnitude due to the appearance of the charged domain walls has been revealed. The difference of forward and reverse polarization reversals was attributed to the clamped switching conditions.
Coupled Raman-Raman modes in the ionic Raman scattering process
Authors: Gu Mingqiang , Rondinelli James M.
Published: September 2018

We employ a lattice Hamiltonian to examine the dynamics of coupled normal modes excited through a nonlinear phononic process, extending the model beyond infrared and first-order Raman active mode couplings to include interactions between symmetry-allowed Raman active modes. We examine the strength of the interactions between two Raman active modes on the targeted driven-mode dynamics to confirm that all symmetry allowed Raman modes interact with each other. We apply the model to the correlated insulating ferromagnet YTiO3 and present the resulting renormalization effects on the driven-mode dynamics from the anharmonic interactions. Owing to the dependence of the displacive amplitude of the Raman active mode on such interactions, especially for those modes with small amplitude, we suggest that models of anharmonic phononic coupling in materials with electronic, ferroic, or superconducting properties derived from competing Raman-like distortions should include these low-order terms in the equations of motion describing the excited phonons to obtain accurate physical models.
Experimental and numerical analyses of multi-DBD plasma actuators to reduce wind loads and modify local flow on the roofs of low-rise buildings
Authors: Zhang Xuewen , Li Zhengnong , Wang Chequan , Hu Jiaxing , Zhou Lifen
Published: September 2018

The present study experimentally and numerically investigates the feasibility of applying multiple dielectric barrier discharge (multi-DBD) plasma actuators to reduce wind loads and modify local flow field on the roofs of low-rise buildings. Four arrangements of multi-DBD plasma actuators are placed on the roofs and induce four directions of wall jets. The results show that mean and peak negative pressure coefficients are negative no matter the plasma actuation is on or off. These wall jets decrease the absolute values of these pressure coefficients in different roof regions and succeed in modifying the local flow around the roof. The wall jet blowing from the trailing edge to the leading edge has the best effect on wind loads, since the absolute values of mean and peak negative pressure coefficients are respectively reduced by about 20% and 12% near the leading edge. The different variations of wind loads and the local flow for all arrangements are due to the compact of the directionality of the wall jets. The wall jet produces a strong suction region at the beginning of the wall jet, which leads to an obvious enhancement of wind loads in this region. Meanwhile, the wall jet induces a strong pressure region at the back of the wall jet, resulting in an apparent decline of wind loads.
Accurate placement of single nanoparticles on opaque conductive structures
Authors: Nikolay Niko , Sadzak Nikola , Dohms Alexander , Lubotzky Boaz , Abudayyeh Hamza , Rapaport Ronen , Benson Oliver
Published: September 2018

Single quantum emitters coupled to different plasmonic and photonic structures are key elements for integrated quantum technologies. In order to fully exploit these elements, e.g., for quantum enhanced sensors or quantum repeaters, a reliable fabrication method as enabling technology is crucial. In this work, we present a method that allows for positioning of individual nanocrystals containing single quantum light sources on non-transparent conductive samples with sub-micrometer precision. We induce long-range electrostatic forces between an atomic force microscope tip, which carries a nanoparticle, and the target surface. This allows for mapping of the target area in the non-contact mode. Then, the placement site can be identified with high accuracy without any tip approach, eliminating the risk of a particle loss. We demonstrate the strength of the method by transferring a diamond nanocrystal containing a single nitrogen-vacancy defect to the center of a micrometer-sized silver bullseye antenna with nanometer resolution. Our approach provides a simple and reliable assembling technology for positioning single nano-objects on opaque substrates with high reproducibility and precision.
New Products
Authors: Mandelis Andreas
Published: September 2018

In order to supplement manufacturers’ information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Physical basis for long-distance communication along meiotic chromosomes
Authors: Fowler Kyle R. , Hyppa Randy W. , Cromie Gareth A. , Smith Gerald R.
Published: September 2018

Viable gamete formation requires segregation of homologous chromosomes connected, in most species, by cross-overs. DNA double-strand break (DSB) formation and the resulting cross-overs are regulated at multiple levels to prevent overabundance along chromosomes. Meiotic cells coordinate these events between distant sites, but the physical basis of long-distance chromosomal communication has been unknown. We show that DSB hotspots up to ∼200 kb (∼35 cM) apart form clusters via hotspot-binding proteins Rec25 and Rec27 in fission yeast. Clustering coincides with hotspot competition and interference over similar distances. Without Tel1 (an ATM tumor-suppressor homolog), DSB and crossover interference become negative, reflecting coordinated action along a chromosome. These results indicate that DSB hotspots within a limited chromosomal region and bound by their protein determinants form a clustered structure that, via Tel1, allows only one DSB per region. Such a “roulette” process within clusters explains the observed pattern of crossover interference in fission yeast. Key structural and regulatory components of clusters are phylogenetically conserved, suggesting conservation of this vital regulation. Based on these observations, we propose a model and discuss variations in which clustering and competition between DSB sites leads to DSB interference and in turn produces crossover interference.
Human influences on the strength of phenotypic selection
Authors: Fugère Vincent , Hendry Andrew P.
Published: September 2018

Human activities are driving rapid phenotypic change in many species, with harvesting considered to be a particularly potent evolutionary force. We hypothesized that faster evolutionary change in human-disturbed populations could be caused by a strengthening of phenotypic selection, for example, if human disturbances trigger maladaptation and/or increase the opportunity for selection. We tested this hypothesis by synthesizing 1,366 phenotypic selection coefficients from 37 species exposed to various anthropogenic disturbances, including harvest. We used a paired design that only included studies measuring selection on the same traits in both human-disturbed and control (not obviously human-disturbed “natural”) populations. Surprisingly, this meta-analysis did not reveal stronger selection in human-disturbed environments; in fact, we even found some evidence that human disturbances might slightly reduce selection strength. The only clear exceptions were two fisheries showing very strong harvest selection. On closer inspection, we discovered that many disturbances weakened selection by increasing absolute fitness and by decreasing the opportunity for selection—thus explaining what initially seemed a counterintuitive result. We discuss how human disturbances can sometimes weaken rather than strengthen selection, and why measuring the total effect of disturbances on selection is exceedingly difficult. Despite these challenges, documenting human influences on selection can reveal disturbances with particularly strong effects (e.g., fishing), and thus better inform the management of populations exposed to these disturbances.
Pressure-induced phase transitions and superconductivity in a black phosphorus single crystal
Authors: Li Xiang , Sun Jianping , Shahi Prashant , Gao Miao , MacDonald Allan H. , Uwatoko Yoshiya , Xiang Tao , Goodenough John B. , Cheng Jinguang , Zhou Jianshi
Published: September 2018

Significance

A high-pressure study of a black phosphorus crystal establishes a rich phase diagram, including Weyl semimetal and superconducting states, Lifshitz-type semiconductor–semimetal transitions, and two structural phase transitions. Transport properties and quantum oscillations under high pressure provide critically valuable information to understand the physics of these new phases. The pressure dependence of physical properties has been reliably measured under hydrostatic pressure and applied magnetic fields using a large-volume apparatus. Superconductivity in the A7 phase has been found to exhibit the largest magnetoresistance effect observed in its normal state so far. The Bardeen–Cooper–Schrieffer superconductivity in the A7 phase identified by the experiment can be accounted for by the phonon mechanism based on a first-principles calculation.
Health and safety considerations.
Authors: Kelanaputra E. S. , Nelson S. P. C. , Setiawati U. , Sitepu B. , Nur F. , Forster B. P. , Purba A. R.
Published: September 2018

All field and laboratory operations should have standard health and safety protocols. These may vary according to local requirements and standards. Some equipment will also come with instructions on proper use, which may involve training, including health and safety issues. Failure to abide by these can result in accidents and personal injury (serious and minor); neglect of health and safety issues may incur penalties such as fines or cessation in field and laboratory activities. Guidelines in health and safety issues relating to crossing in oil palm are given below.
Introduction.
Authors: Setiawati U. , Sitepu B. , Nur F. , Forster B. P. , Dery S.
Published: September 2018

A brief history of the evolution of the oil palm crop is provided, from domestication and small-scale production in Africa (its centre of origin/diversity) to crop expansion, especially in South-east Asia, in becoming the world's top oil crop. Knowledge of the biology and genetics of oil palm are fundamental in understanding how the crop can be developed through crossing and breeding, and key biological factors such as flowering, outcrossing and genetics are described. A prerequisite for breeding is the crossing of parental lines that carry desirable traits; thus, the germplasm (genetic variation) available to breeders is critical for success. Traditional traits of interest are yield and quality. More recently, disease and pest resistance have become important, as too have novel traits that may be exploited in developing a crop that can be harvested mechanically. Crossing is not only performed to develop and improve elite breeding lines but also is an essential component of commercial seed production.
Pollen collection and storage.
Authors: Setiawati U. , Sitepu B. , Nur F. , Forster B. P. , Dery S.
Published: September 2018

Shed pollen of oil palm is binucleate, it has two cells (one vegetative and one generative), and can live for about a week in situ. However, fresh pollen can be collected from flowering male inflorescences, purified and stored for over 20 years in cold, desiccated and vacuumed conditions. The processes involved are described. Male inflorescences are isolated in bags prior to flowering, to ensure pollen purity, and treated to prevent insects bringing in pollen from other sources. Specialized isolation bags are used that contain a smaller pollen-collecting bag and a window to observe development. Male inflorescences are harvested during the late stages of anthesis and placed in a hot room to encourage the remaining florets to open and shed pollen. The collected pollen is purified by sieving, drying and vacuum packing in ampoules and stored ready for use. Pollen is collected from isolated male inflorescences. These may involve tall trees that require ladders and safety equipment. Hazardous chemicals and sharp knives are used in field operations; see Chapter 2 of this manual for guidance.
The cresting wave: a new moving spotlight theory
Authors: Miller Kristie
Published: September 2018

One argument for the moving spotlight theory is that it better explains our temporal phenomenology than does any static theory. In this paper it is argued that insofar as moving spotlight theorists take this to be a sound argument they ought embrace a new version of the moving spotlight theory according to which the moving spotlight is a cresting wave of causal efficacy. Hence a range of fundamental properties are temporary because presentness synchronically changesthe fundamental properties that are instantiated in the present moment, and our experiences of presentness co-varies with presentness, allowing us to phenomenologically detect presentness.
Assertion and transparent self-knowledge
Authors: Marcus Eric , Schwenkler John
Published: September 2018

We argue that honesty in assertion requires non-empirical knowledge that what one asserts is what one believes. Our argument proceeds from the thought that to assert honestly, one must follow and not merely conform to the norm ‘Assert that p only if you believe that p’. Furthermore, careful consideration of cases shows that the sort of doxastic self-knowledge required for following this norm cannot be acquired on the basis of observation, inference, or any other form of detection of one's own doxastic states. It is, as we put it, transparent rather than empirical self-knowledge.
Proteins that control the geometry of microtubules at the ends of cilia
Authors: Louka Panagiota , Vasudevan Krishna Kumar , Guha Mayukh , Joachimiak Ewa , Wloga Dorota , Tomasi Raphaël F.-X. , Baroud Charles N. , Dupuis-Williams Pascale , Galati Domenico F. , Pearson Chad G. , Rice Luke M. , Moresco James J. , Yates John R. , Jiang Yu-Yang , Lechtreck Karl , Dentler William , Gaertig Jacek
Published: September 2018

Cilia, essential motile and sensory organelles, have several compartments: the basal body, transition zone, and the middle and distal axoneme segments. The distal segment accommodates key functions, including cilium assembly and sensory activities. While the middle segment contains doublet microtubules (incomplete B-tubules fused to complete A-tubules), the distal segment contains only A-tubule extensions, and its existence requires coordination of microtubule length at the nanometer scale. We show that three conserved proteins, two of which are mutated in the ciliopathy Joubert syndrome, determine the geometry of the distal segment, by controlling the positions of specific microtubule ends. FAP256/CEP104 promotes A-tubule elongation. CHE-12/Crescerin and ARMC9 act as positive and negative regulators of B-tubule length, respectively. We show that defects in the distal segment dimensions are associated with motile and sensory deficiencies of cilia. Our observations suggest that abnormalities in distal segment organization cause a subset of Joubert syndrome cases.
Static friction on a ball rolling down an incline
Authors: Cross Rod
Published: September 2018

A ball that rolls without sliding down an inclined plane requires a small static friction force to prevent the ball sliding down the incline. The magnitude of that force is investigated by considering the force needed to prevent the contact point from slipping.
FA01.01: MINIMALLY INVASIVE APPROACH RESULTS IN BETTER OUTCOME COMPARED TO OPEN ESOPHAGECTOMY—A PROPENSITY SCORE MATCHED ANALYSIS
Authors: Kwan Kit Chan Desmond , Siu Yin Chan Fion , King Hung Tong Daniel , Yu Hong Wong Ian , Lai Yin Wong Claudia , Ting Law Tsz , Ying Kit Law Simon
Published: September 2018

Background

Esophagectomy remains the mainstay treatment for esophageal cancer. Minimally invasive techniques have gained popularity in recent years. Whether minimally invasive methods result in equivalent or superior outcome to open esophagectomy or not is still controversial. The aim of the current study is to compare outcomes of minimally invasive and open esophagectomy from a single institution, using propensity score matching to lessen biases.

Methods

From 1994–2016, 724 patients with squamous cell cancer of the esophagus who underwent esophagectomy were studied. Data were retrieved from a prospectively collected database. Patients were divided into two groups: 453 had open esophagectomy (open group), and 271 had VATS esophagectomy with gastric mobilization either via laparotomy or laparoscopically (MIE group). A propensity score was generated for each patient based on age, gender, tumor level, use of neoadjuvant therapy, American Society of Anaesthesiologists (ASA) score, pathologic stage of disease, site of anastomosis, and residual tumour (R) categories and the two matched groups were compared in clinico-pathological features, morbidity and mortality rates, and long-term survival. All statistical calculations were performed with SPSS version 24 (SPSS, Chicago, IL).

Results

A total of 158 patients in MIE and 187 in open group are matched for comparison (1:3 matching). MIE resulted in less blood loss (220 vs 400ml, P < 0.001) but longer operative time (461 vs 305 mins, P < 0.001). Wound infection (3.7% vs 10.7%, P = 0.01) and respiratory complications (29% vs 55.1%, P < 0.001) were also less in MIE group. Except for a higher rate of conduit ischemia (6.3% vs 1.6%, P = 0.02), MIE had comparable surgical outcomes with open technique in rates of anastomotic leakage (5.7% vs 5.3%, P = 0.89), recurrent laryngeal nerve palsy (20.1% vs 18.7%, P = 0.10), reoperation (10.8% vs 8.6%, P = 0.49), and length of postoperative hospital stay (13 vs 14 days, P = 0.50). Lymph node harvest was significantly higher with MIE (35 vs 21, P < 0.001), a longer median survival was also evident compared to the open group (42.3 vs 24.7 months, P = 0.03).

Conclusion

Although requiring longer operative time, MIE led to less wound and respiratory complications without jeopardizing surgical and oncological outcome. The more comprehensive lymphadenectomy could potentially improve prognosis.

Disclosure

All authors have declared no conflicts of interest.
FA01.02: THE EFFECT OF POSTOPERATIVE COMPLICATIONS AFTER MIE ON LONG-TERM SURVIVAL: A RETROSPECTIVE, MULTI-CENTER COHORT STUDY
Authors: Fransen Laura , Berkelmans Gijs , Asti Emanuele , Van Berge Henegouwen Mark , Berlth Felix , Bonavina Luigi , Brown Andrew , Bruns Christiane , Gisbertz Suzanne , Grimminger Peter , Gutschow Christian , Hölscher Arnulf , Kauppi Juha , Lagarde Sjoerd M , Mercer Stuart , Moons Johnny , Nafteux Philippe , Nilsson Magnus , Palazzo Francesco , Pattyn Piet , Philippron Annouck , Raptis Dimitri , Räsänen Jari , Rosato Ernest , Rouvelas Ioannis , Schmidt Henner , Schneider Paul , Schröder Wolfgang , Wijnhoven Bas P L , Grard A P , Nieuwenhuijzen  , Luyer Misha
Published: September 2018

Background

Esophagectomy has a high incidence of postoperative morbidity. Complications lead to a decreased short-term survival, however the influence of those complications on long-term survival is still unclear. Most of the performed studies are small, single center cohort series with inconclusive or conflicting results. Minimally invasive esophagectomy (MIE) has been shown to be associated with a reduced postoperative morbidity. In this study, the influence of complications on long-term survival for patients with esophageal cancer undergoing a MIE were investigated.

Methods

Data was collected from the EsoBenchmark database, a collaboration of 13 high-volume centers routinely performing MIE. Patients were included in this database from June 1, 2011 until May 31, 2016. Complications were scored according to the Clavien-Dindo (CD) classification for surgical complications. Major complications were defined as a CD grade ≥ 3. The data were corrected for 90-day mortality to correct for the short-term effect of postoperative complications on mortality. Overall survival was analyzed using the Kaplan Meier, log rank- and (uni- and multivariable) Cox-regression analyses.

Results

A total of 926 patients were eligible for analysis. Mean follow-up time was 30.8 months (SD 17.9). Complications occurred in 543 patients (59.2%) of which 39.3% had a major complication. Anastomotic leakage (AL) occurred in 135 patients (14.5%) of which 9.2% needed an intervention (CD grade ≥ 3). A significant worse long-term survival was observed in patients with any AL (HR 1.73, 95% CI 1.29–2.32, P < 0.001) and for patients with AL CD grade ≥3 (HR 1.86, 95% CI 1.32–2.63, P < 0.001). Major cardiac complications occurred in 18 patients (1.9%) and were related to a decreased long-term survival (HR 2.72, 95% CI 1.38–5.35, p 0.004). For all other complications, no significant influence on long-term survival was found.

Conclusion

The occurrence and severity of anastomotic leakage and cardiac complications after MIE negatively affect long-term survival of esophageal cancer patients.

Disclosure

All authors have declared no conflicts of interest.
FA02.03: TIMING OF REFLUX ESOPHAGITIS (RE) AND BARRET’S ESOPHAGUS (BE) DEVELOPMENT IN PATIENTS AFFECTED BY GERD AFTER HELLER MYOTOMY FOR ESOPHAGEAL ACHALASIA
Authors: Tassi Valentina , Lugaresi Marialuisa , Mattioli Benedetta , Daddi Niccolò , Di Simone Massimo , Bassi Francesco , Mattioli Sandro
Published: September 2018

Background

In order to acquire data on development of RE and BE in patients affected by GERD after Heller myotomy, we investigated a group of these patients who had long term endoscopic follow up. Data acquired in this group and in a group of patients affected by primary GERD and BE were compared.

Methods

In 1973 our group established a research protocol and data base to include patients affected by esophageal diseases observed since 1955 and successively, who were followed up according to defined protocols. A semi quantitative Visick modified scale (RS0 absence; RS3 maximal severity) was adopted for evaluation of reflux symptoms. Among 465 achalasia patients submitted to Heller myotomy in the period 1955–2016, 42 (57.14% men, median age 50 years IQR 44–58 years) post operatively complained grade RS2–3 reflux symptoms and had long term endoscopic/histologic follow up; 42 patients affected by typical GERD and Barret's esophagus, selected according to age and sex with the ‘Frequency matching’ process formed the control group.

Results

Twenty-six patients were submitted to Heller myotomy without antireflux procedure between 1955 and 1977, 16 to Heller-Dor successively. Patients experienced moderate-severe (SR2–3) GER symptoms after a median period of 20 months (IQR 10–86.5 months) since myotomy; in 100% RE was detected after a median period of 34.5 months (IQR 19.25–56.5 months), in 47.61% BE after a median period of 80 months (IQR 52–123 months) since GER symptoms onset. In primary GERD group, in the absence of medical therapy all patients complained of SR2–3 GER symptoms, RE was diagnosed after a median period of 72.5 months (IQR 59.25–120 months) and BE after a median period of 128 months (IQR 91–163.75 months) since GER symptoms onset. Time for RE (P < 0.001) and BE (P = 0.002) development in achalasia patients was significantly shorter with respect to timing in GERD population.

Conclusion

In achalasia patients myotomy induced Barret's esophagus occurs much earlier than in typical GERD patients. This information should be considered for the treatment of post Heller GERD and for selection of candidates to POEM.

Disclosure

All authors have declared no conflicts of interest.
FA02.06: VOLUMETRIC LASER ENDOMICROSCOPY GLAND QUANTIFICATION CAN GUIDE EN-BLOC RESECTION IN DYSPLASTIC BARRETT’S ESOPHAGUS
Authors: Kamboj Amrit , Kahn Allon , Sawas Tarek , Lutzke Lori , Wang Kenneth , Leggett Cadman
Published: September 2018

Background

Endoscopic mucosal resection (EMR) can be performed en-bloc in Barrett's esophagus (BE) lesions that are ≤2 cm in size. The true size of a BE lesion may be underestimated under white light endoscopy, limiting the rate of en-bloc resection. Volumetric laser endomicroscopy (VLE) provides high-resolution cross-sectional imaging of BE. A greater number of VLE glands are associated with BE dysplasia and may help predict lesion size. The aim of this study was to determine the association between VLE gland count and outcome of resection.

Methods

EMR specimens from patients with a history of dysplastic BE were imaged with VLE. EMRs performed on BE lesions ≤2cm in size with intent at en-bloc resection were included. Manual quantification of epithelial glands was performed in blinded fashion. Image visualization enhancement software was used to quantify the surface area occupied by epithelial glands on en-face VLE. Histologic en-bloc (R0) and incomplete (R1) resection of the targeted lesion was defined by the absence and presence of dysplasia and/or cancer at the specimen margins respectively.

Results

The study sample consisted of 37 EMRs from 31 patients. The mean (SD) size of EMRs was 1.04 (0.37) cm. Pathology showed low-grade dysplasia (N = 12), high-grade dysplasia (N = 19), and intramucosal cancer (N = 6). The en-bloc resection rate was 37.8% (R0: N = 14; R1: N = 23). The mean (SD) number of epithelial glands was 13.0 (6.7) and 28.8 (23.9) for R0 and R1 specimens, respectively, with a statistically significant mean difference of 15.8 glands (95% CI: 2–29, P = 0.02) between the two groups. A gland count of 28 or higher per EMR specimen predicted R1 with 100% sensitivity and 39% specificity (ROC: 0.69). The mean (SD) surface area occupied by epithelial glands in R0 and R1 specimens was 0.98 (1.1) mm2 and 2.3 (2.4) mm2, respectively. There was strong correlation between manual gland counts and epithelial gland surface area (R2: 0.81, P < 0.001).

Conclusion

A higher number of VLE glands in EMR specimens is associated with a lower en-bloc resection rate suggesting that white-light endoscopy underestimates lesion size and that VLE may have a potential role in lesion margin assessment.

Disclosure

All authors have declared no conflicts of interest.
Carriage of the Toxic Shock Syndrome Toxin Gene by Contemporary Community-Associated Staphylococcus aureus Isolates
Authors: Parrish Katelyn L , Wylie Kristine M , Reich Patrick J , Hogan Patrick G , Wylie Todd N , Kennedy Colleen R , Lainhart William , Hunstad David A , Burnham Carey-Ann D , Fritz Stephanie A
Published: September 2018

We report here the prevalence of the tst-1 gene among 252 methicillin-susceptible Staphylococcus aureus (MSSA) isolates and 458 methicillin-resistant S aureus (MRSA) isolates collected from 531 subjects between 2008 and 2017, one of which was recovered from a child with MRSA toxic shock syndrome. tst-1 was encoded by 43 (6%) S aureus isolates overall: 42 (16.7%) MSSA isolates and 1 (0.2%) MRSA isolate (P < .001).
Long-Term Outcomes of Endovascular Treatment of Indirect Carotid Cavernous Fistulae: Superior Efficacy, Safety, and Durability of Transvenous Coiling Over Other Techniques
Authors: Alexander Matthew D , Halbach Van V , Hallam Danial K , Cooke Daniel L , Ghodke Basavaraj V , Dowd Christopher F , Amans Matthew R , Hetts Steven W , Higashida Randall T , Meyers Philip M
Published: September 2018

BACKGROUND

Endovascular surgery is the first-line treatment for indirect cavernous carotid fistulae (CCFs). This study compares multiple treatment techniques.

OBJECTIVE

To compare endovascular techniques for indirect CCF treatment.

METHODS

Retrospective analysis was performed of prospectively maintained records at 4 centers, identifying patients undergoing indirect CCF embolization. Demographics, symptoms, and lesion characteristics were recorded. Medical records were reviewed for changes in symptoms, delayed complications, and angiographically proven recurrence. Univariate and multivariate analyses were performed to identify impacts of the above characteristics on outcomes.

RESULTS

Sufficient records were available for 267 patients treated between January 1987 and December 2016. Obliteration was achieved in 86.5% patients, occurring in 86.9% of exclusively transvenous treatments and 79.5% of other treatments. Obliteration rates were highest following transvenous embolization using coils compared to all other materials (likelihood ratio [LR] 5.0, P = .024). Complications were less common with coil embolization compared to other materials (LR 0.070, P < .001). Embolization with liquid embolics resulted in higher complication rates (LR 10.2, P = .002), although risk was reduced when used in conjunction with coils. Angiographically confirmed recurrence was more common following embolization with polyvinyl alcohol (LR 9.9, P = .004) and when multiple embolic agents were used (LR 6.6, P = .018). Delayed development of symptoms following embolization was less common following embolization with coils (LR 0.20, P = .030) and more common following embolization with liquids (LR 6.5, P = .014).

CONCLUSION

To treat indirect CCFs, transvenous coil embolization is the safest and most effective technique. Liquid embolics are less effective and have more complications and should be carefully considered only in extenuating circumstances.
Occult Hepatitis B Virus Infection: An Old Entity With Novel Clinical Involvements
Authors: Malagnino Vincenzo , Fofana Djeneba Bocar , Lacombe Karine , Gozlan Joel
Published: September 2018

Background

Occult hepatitis B infection (OBI) is recognized as a risk factor for cirrhosis and hepato-cellular carcinoma. However, OBI brings together a large spectrum of patients who might harbor different characteristics and prognosis.

Methods

We analyzed the databases of a university hospital in Paris to identify OBI among patients (n = 3966) concomitantly tested for hepatitis B virus (HBV) DNA and serology during a 7-year period. OBI patients were gathered into clinical entities according to their clinical records.

Results

Forty-seven OBIs were identified (1.2%). All patients had detectable anti-HBc, isolated (n = 26) or associated with anti-HBs (n = 21). The proportion of OBIs was 3.4% for patients with isolated anti-HBc and 4.2% for patients with both anti-HBc and anti-HBs. Four clinical categories of OBI patients were identified: patients with a passed HBV infection with HBs Ag clearance (group A, 23.4%); HBV-exposed patients receiving immunosuppressive therapy (group B, 29.8%); HIV/HBV-coinfected patients with therapy discontinuation (group C, 17%); HBV-exposed patients with severe liver conditions (group D, 29.8%). Significant follow-up was available for 32 patients, showing a more deleterious prognosis in group D patients, associated more with their underlying condition than the OBI status.

Conclusions

OBI is a heterogeneous condition with various clinical implications.
Identification of a New Haplotype of ‘Candidatus Liberibacter solanacearum’ in Solanum tuberosum
Authors: Swisher Grimm K. D. , Garczynski S. F.
Published: September 2018

In 2017, potato tubers suspected of being infected with the bacterium ‘Candidatus Liberibacter solanacearum’ were received from the Animal and Plant Health Inspection Service in the United States. A total of 368 chipping tubers were observed for internal symptoms of zebra chip disease, which is associated with ‘Ca. L. solanacearum’ infection in the United States, Mexico, Central America, and New Zealand. A single tuber sliced at the stem end showed classic zebra chip symptoms of darkened medullary rays, with streaking and necrotic flecking. The symptomatic tuber was confirmed positive for the bacterium by polymerase chain reaction targeting three different ‘Ca. L. solanacearum’ genes. Sequence analysis of these three genes, and subsequent BLAST analysis, identified the pathogen with 99, 98, and 97% identity to ‘Ca. L. solanacearum’ for the 16S ribosomal RNA gene, 50S ribosomal proteins L10/L12 genes, and the outer membrane protein gene, respectively. Sequence analysis did not identify the sample as one of the six known haplotypes of ‘Ca. L. solanacearum,’ indicating that a seventh haplotype of the pathogen was identified. This new haplotype, designated haplotype F, is now the third haplotype of the bacterium that infects Solanum tuberosum in the United States.
Evaluation of New Oomycota Fungicides for Management of Phytophthora Root Rot of Citrus in California
Authors: Hao Wei , Gray Morgan A. , Förster Helga , Adaskaveg James E.
Published: September 2018

Phytophthora root rot, caused by several species of Phytophthora, is an important disease of citrus in California and other growing regions. For chemical management, mefenoxam and potassium phosphite have been available for many years, and resistance in Phytophthora spp. has been reported for both compounds. We evaluated the efficacy of the new Oomycota fungicides ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin, each with a different mode of action, against Phytophthora root rot of citrus in field and greenhouse studies. Root balls of navel orange trees on ‘Carrizo citrange’ rootstock were inoculated with P. nicotianae at planting in the field in fall 2013. Applications with 11 fungicide treatments were made 5 weeks after planting, in spring and fall 2014, and in spring 2015. Feeder roots and adjacent soil were collected before or after application. All of the new fungicides significantly reduced root rot incidence and Phytophthora soil populations to very low levels as compared with the control starting after the first application. Mefenoxam was only effective when a high label rate was used in the fourth application. Selected treatments also increased tree canopy size, trunk diameter, and fruit yield as compared with the control. A rate comparison with the four new fungicides was initiated in summer 2016 in another field trial using navel orange trees inoculated with P. citrophthora. Minimum effective rates to reduce Phytophthora root rot incidence and pathogen soil populations were determined after one and two applications in fall 2016 and summer 2017, respectively. Greenhouse studies confirmed the efficacy of the new fungicides. Based in part on our studies, fluopicolide recently received a federal and oxathiapiprolin a full registration for use on citrus, and registrations for ethaboxam and mandipropamid have been requested. These new compounds will provide highly effective treatment options and resistance management strategies using rotation and mixture programs for the control of Phytophthora root rot of citrus.