bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative comparison of delayed ferumoxytol T1 enhancement with immediate gadoteridol enhancement in high grade gliomas
Authors: Horváth Andrea , Varallyay Csanad G. , Schwartz Daniel , Toth Gerda B. , Netto Joao P. , Barajas Ramon , Várallyay Péter , Szidonya László , Firkins Jenny , Youngers Emily , Fu Rongwei , Ambady Prakash , Bogner Péter , Neuwelt Edward A.
Published: December 2017

Purpose

Delayed ferumoxytol enhancement on T1‐weighted images appears visually similar to gadoteridol enhancement. The purpose of this study was to quantitatively compare ferumoxytol T1 enhancement to gadoteridol enhancement with an objective, semi‐automated method.

Methods

206 sets of post‐gadoteridol and 24 h post‐ferumoxytol T1‐weighted scans from 58 high grade glioma patients were analyzed (9 pre‐chemoradiation, 111 < 90 days post‐chemoradiation, 21 > 90 days post‐chemoradiation, 65 post‐bevacizumab scans). Enhancement volumes and signal intensities normalized to normal appearing tissue proximal to enhancement were calculated with a semi‐automated method. Enhancement cube root volumes (D) and signal intensities (SI) were compared between the 2 contrast agents, and relative difference of D and SI were compared in different treatment groups with multivariate analysis. Within patient differences in D and SI before and after treatment with bevacizumab or steroid were assessed in 26 patients in each treatment group.

Results

When compared to gadoteridol, ferumoxytol D was 13.83% smaller and SI was 7.24% lower (P < 0.0001). The relative differences in D and SI between the 2 contrast agents were not significantly different between treatment groups (P > 0.05). Relative difference in D and SI did not change significantly in response to bevacizumab (P = 0.5234 and P = 0.2442, respectively) or to steroid (P = 0.3774, P = 0.0741) in the within patient comparison.

Conclusion

The correlation between the 2 contrast agents’ enhancement size and signal intensity and their similar behavior in response to therapy suggest that ferumoxytol can be used for revealing enhancement in high grade glioma patients. Magn Reson Med 80:224–230, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
A z‐gradient array for simultaneous multi‐slice excitation with a single‐band RF pulse
Authors: Ertan Koray , Taraghinia Soheil , Sadeghi Alireza , Atalar Ergin
Published: December 2017

Purpose

Multi‐slice radiofrequency (RF) pulses have higher specific absorption rates, more peak RF power, and longer pulse durations than single‐slice RF pulses. Gradient field design techniques using a z‐gradient array are investigated for exciting multiple slices with a single‐band RF pulse.

Theory and Methods

Two different field design methods are formulated to solve for the required current values of the gradient array elements for the given slice locations. The method requirements are specified, optimization problems are formulated for the minimum current norm and an analytical solution is provided. A 9‐channel z‐gradient coil array driven by independent, custom‐designed gradient amplifiers is used to validate the theory.

Results

Performance measures such as normalized slice thickness error, gradient strength per unit norm current, power dissipation, and maximum amplitude of the magnetic field are provided for various slice locations and numbers of slices. Two and 3 slices are excited by a single‐band RF pulse in simulations and phantom experiments.

Conclusion

The possibility of multi‐slice excitation with a single‐band RF pulse using a z‐gradient array is validated in simulations and phantom experiments. Magn Reson Med 80:400–412, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
HeS‐CoP: Heuristic switch‐controller placement scheme for distributed SDN controllers in data center networks
Authors: Kim Woojoong , Li Jian , Hong James Won‐Ki , Suh Young‐Joo
Published: December 2017

Software‐defined networking (SDN) has been widely researched and used to manage large‐scale networks such as data center networks (DCNs). An early stage of SDN controller experienced low responsiveness, low scalability, and low reliability. To solve these problems, distributed SDN controllers have been proposed. The concept of distributed SDN controllers distributes control messages among multiple SDN controllers. However, distributed SDN controllers must assign a master controller for each networking devices. Most previous studies, however, did not consider the characteristics of DCNs. Thus, they are not suitable to operate in DCNs. In this paper, we propose HeS‐CoP, a heuristic switch‐controller placement scheme for distributed SDN controllers in DCNs. With the control traffic load and CPU load, HeS‐CoP decides when our scheme should be performed in DCNs. To show the feasibility of HeS‐CoP, we designed and implemented an orchestrator that contains our proposed scheme and then evaluated our proposed scheme. As a result, our proposed scheme well distributes the control traffic load, decreases the average CPU load, and reduces the packet delay.
Computational certification under limited experiments
Authors: Fish Jacob , Yuan Zifeng , Kumar Rajesh
Published: December 2017

A computational certification framework under limited experimental data is developed. By this approach, a high‐fidelity model (HFM) is first calibrated to limited experimental data. Subsequently, the HFM is employed to train a low‐fidelity model (LFM). Finally, the calibrated LFM is utilized for component analysis. The rational for utilizing HFM in the initial stage stems from the fact that constitutive laws of individual microphases in HFM are rather simple so that the number of material parameters that needs to be identified is less than in the LFM. The added complexity of material models in LFM is necessary to compensate for simplified kinematical assumptions made in LFM and for smearing discrete defect structure. The first‐order computational homogenization model, which resolves microstructural details including the structure of defects, is selected as the HFM, whereas the reduced‐order homogenization is selected as the LFM. Certification framework illustration, verification, and validation are conducted for ceramic matrix composite material system comprised of the 8‐harness weave architecture. Blind validation is performed against experimental data to validate the proposed computational certification framework.
A Fourier transformation‐based method for gradient‐enhanced modeling of fatigue
Authors: Kindrachuk Vitaliy M. , Titscher Thomas , Unger Jörg F.
Published: December 2017

A key limitation of the most constitutive models that reproduce a degradation of quasi‐brittle materials is that they generally do not address issues related to fatigue. One reason is the huge computational costs to resolve each load cycle on the structural level. The goal of this paper is the development of a temporal integration scheme, which significantly increases the computational efficiency of the finite element method in comparison to conventional temporal integrations. The essential constituent of the fatigue model is an implicit gradient‐enhanced formulation of the damage rate. The evolution of the field variables is computed as a multiscale Fourier series in time. On a microchronological scale attributed to single cycles, the initial boundary value problem is approximated by linear BVPs with respect to the Fourier coefficients. Using the adaptive cycle jump concept, the obtained damage rates are transferred to a coarser macrochronological scale associated with the duration of material deterioration. The performance of the developed method is hence improved due to an efficient numerical treatment of the microchronological problem in combination with the cycle jump technique on the macrochronological scale. Validation examples demonstrate the convergence of the obtained solutions to the reference simulations while significantly reducing the computational costs.
Time finite element based Moreau‐type integrators
Authors: Capobianco G. , Eugster S. R.
Published: December 2017

With the postulation of the principle of virtual action, we propose, in this paper, a variational framework for describing the dynamics of finite dimensional mechanical systems, which contain frictional contact interactions. Together with the contact and impact laws formulated as normal cone inclusions, the principle of virtual action directly leads to the measure differential inclusions commonly used in the dynamics of nonsmooth mechanical systems. The discretization of the principle of virtual action in its strong and weak variational form by local finite elements in time provides a structured way to derive various time‐stepping schemes. The constitutive laws for the impulsive and nonimpulsive contact forces, ie, the contact and impact laws, are treated on velocity‐level by using a discrete contact law for the percussion increments in the sense of Moreau. Using linear shape functions and different quadrature rules, we obtain three different stepping schemes. Besides the well‐established Moreau time‐stepping scheme, we can present two alternative integrators referred to as symmetric and variational Moreau‐type stepping schemes. A suitable benchmark example shows the superiority of the newly proposed integrators in terms of energy conservation properties, accuracy, and convergence.
A mortar finite element approach for point, line, and surface contact
Authors: Farah P. , Wall W. A. , Popp A.
Published: December 2017

An approach for investigating finite deformation contact problems with frictional effects with a special emphasis on nonsmooth geometries such as sharp corners and edges is proposed in this contribution. The contact conditions are separately enforced for point contact, line contact, and surface contact by employing 3 different sets of Lagrange multipliers and, as far as possible, a variationally consistent discretization approach based on mortar finite element methods. The discrete unknowns due to the Lagrange multiplier approach are eliminated from the system of equations by employing so‐called dual or biorthogonal shape functions. For the combined algorithm, no transition parameters are required, and the decision between point contact, line contact, and surface contact is implicitly made by the variationally consistent framework. The algorithm is supported by a penalty regularization for the special scenario of nonparallel edge‐to‐edge contact. The robustness and applicability of the proposed algorithms are demonstrated with several numerical examples.
Political will and government anti‐corruption efforts: What does the evidence say?
Authors: Ankamah Samuel Siebie , Manzoor E Khoda S M
Published: December 2017

“Political will” is oft‐cited as the major obstacle to government's anti‐corruption efforts. Notwithstanding, there is remarkably little systematic analysis of the concept, with some scholars describing it as the “slipperiest concept in the policy lexicon,” whereas others are calling for its empirical relevance. This paper tries to unpack the “black box” of political will by making it an empirically relevant concept drawing on evidence from two Asian countries; Singapore and Bangladesh. Four key indicators based on the works of earlier scholars are used including origin of the initiative; comprehension and extent of analysis; credible sanctions; and resource dedication and sustenance are used. The paper also uses Transparency International's Corruption Perception Index, World Bank's World Governance Indicators (Control of Corruption and Government Effectiveness), and Political, Economic and Risk Consultancy's annual survey in Asia, as outcome measures. Based on the empirical evidence from the two countries, the paper shows that political will indeed has a positive influence on government's anti‐corruption efforts. Although political will may not be sufficient, it is a necessary condition to fight corruption, and that the difference between the positions of Singapore and Bangladesh on various global corruption league tables may be attributed to political will.
Anti‐oncostatin M antibody inhibits the pro‐malignant effects of oncostatin M receptor overexpression in squamous cell carcinoma
Authors: Kucia‐Tran Justyna A , Tulkki Valtteri , Scarpini Cinzia G , Smith Stephen , Wallberg Maja , Paez‐Ribes Marta , Araujo Angela M , Botthoff Jan , Feeney Maria , Hughes Katherine , Caffarel Maria M , Coleman Nicholas
Published: December 2017

The oncostatin M (OSM) receptor (OSMR) shows frequent gene copy number gains and overexpression in cervical squamous cell carcinomas (SCCs), associated with adverse clinical outcomes. In SCC cells that overexpress OSMR, the major ligand OSM induces multiple pro‐malignant effects, including invasion, secretion of angiogenic factors, and metastasis. Here, we demonstrate, for the first time, that OSMR overexpression in SCC cells activates cell‐autonomous feed‐forward signalling, via further expression of OSMR and OSM and sustained STAT3 activation, despite expression of the negative regulator suppressor of cytokine signalling 3 (SOCS3). The pro‐malignant effects associated with OSMR overexpression are critically mediated by JAK–STAT3 activation, which is induced by exogenous OSM and also by autocrine OSM–OSMR interactions. Importantly, specific inhibition of OSM–OSMR interactions by neutralizing antibodies significantly inhibits STAT3 activation and feed‐forward signalling, leading to reduced invasion, angiogenesis, and metastasis. Our findings are supported by data from 1254 clinical SCC samples, in which OSMR levels correlated with multiple cognate genes, including OSM, STAT3, and downstream targets. These data strongly support the development of OSM–OSMR‐blocking antibodies as biologically targeted therapies against SCCs of the cervix and other anatomical sites. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Donor‐derived, metastatic urothelial cancer after kidney transplantation associated with a potentially oncogenic BK polyomavirus
Authors: Müller David C , Rämö Maarit , Naegele Klaudia , Ribi Sebastian , Wetterauer Christian , Perrina Valeria , Quagliata Luca , Vlajnic Tatjana , Ruiz Christian , Balitzki Beate , Grobholz Rainer , Gosert Rainer , Ajuh Elvis T , Hirsch Hans H , Bubendorf Lukas , Rentsch Cyrill A
Published: December 2017

BK polyomavirus has been linked to urothelial carcinoma in immunosuppressed patients. Here, we performed comprehensive genomic analysis of a BK polyomavirus‐associated, metachronous, multifocal and metastatic micropapillary urothelial cancer in a kidney transplant recipient. Dissecting cancer heterogeneity by sorting technologies prior to array‐comparative genomic hybridization followed by short tandem repeat analysis revealed that the metastatic urothelial cancer was of donor origin (4‐year‐old male). The top 50 cancer‐associated genes showed no key driver mutations as assessed by next‐generation sequencing. Whole genome sequencing and BK polyomavirus‐specific amplification provided evidence for episomal and subgenomic chromosomally integrated BK polyomavirus genomes, which carried the same unique 17‐bp deletion signature in the viral non‐coding control region (NCCR). Whereas no role in oncogenesis could be attributed to the host gene integration in chromosome 1, the 17‐bp deletion in the NCCR increased early viral gene expression, but decreased viral replication capacity. Consequently, urothelial cells were exposed to high levels of the transforming BK polyomavirus early proteins large tumour antigen and small tumour antigen from episomal and integrated gene expression. Surgery combined with discontinuation of immunosuppression resulted in complete remission, but sacrificed the renal transplant. Thus, this report links, for the first time, BK polyomavirus NCCR rearrangements with oncogenic transformation in urothelial cancer in immunosuppressed patients. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Cyclic AMP‐dependent protein kinase catalytic subunit A (PRKACA): the expected, the unexpected, and what might be next
Authors: Stratakis Constantine A
Published: December 2017

Protein kinase A (PKA) or cyclic‐AMP (cAMP)‐dependent kinase was among the first serine–threonine kinases to be molecularly and functionally characterized. For years, it was investigated as the enzyme that mediates cAMP functions in almost all cell systems and organisms studied to date. Despite PKA's critical role in signaling and the long history of investigations of cAMP in oncogenesis (dating back to the 1970s), it was not until relatively recently that PKA defects were found to be directly involved in tumor predisposition. First, PKA's main regulatory subunit, PRKAR1A, was found to be mutated in Carney complex, a genetic syndrome that predisposes to heart tumors (cardiac myxomas) and a variety of other lesions of the endocrine system, including the adrenal cortex, and several cancers, including liver carcinoma. Then, PKA's main catalytic subunit, PRKACA, was found to be mutated in sporadic adrenal tumors and fibrolamellar liver carcinoma. Not surprisingly, therefore, a new research study published in The Journal of Pathology showed PRKACA mutations in sporadic cardiac myxomas. The real question is what other pathologies will be found to be due to PRKACA (or other PKA subunit) defects. The possibilities abound and may show the way for a totally new class of medications that target cAMP signaling to be useful in fighting the corresponding tumors. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
Atomistic insights on the LCST behavior of PMEO2MA in water by molecular dynamics simulations
Authors: Dalgakiran Eray , Tatlipinar Hasan
Published: December 2017

Fully atomistic molecular dynamics simulations of poly(2‐[2‐methoxyethoxy]ethyl methacrylate) (PMEO2MA) in water at temperatures below and above its lower critical solution temperature (LCST) were performed to improve the understanding of its LCST behavior. Atomic trajectories were used to calculate various structural and dynamic properties. Simulation results show that PMEO2MA undergo a distinct coil‐to‐globule transition above LCST. Detailed analyses of the number of first hydration shell water molecules around various atomic regions are revealed that the water solubility of PMEO2MA below LCST is mainly provided by the hydrophobic hydration around the side chain carbon atoms. This is achieved by the cage‐like water network formations which are disrupted when the temperature is increased above LCST, accompanied by significant amount of water molecule release and local water‐ordering reduction, which leads to the LCST phase transition. Furthermore, other analyses such as the number of hydrogen bonds and hydrogen bond lifetimes suggest that intermolecular hydrogen bondings between polymer and water molecules have little effect on the phase transition. Our results will contribute to a better understanding on the LCST phase transition of oligo(ethylene glycol) methyl ether methacrylate (OEGMA)‐based homopolymers at atomistic level that will be useful when designing homo‐ and co‐polymers of OEGMAs with desired properties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 429–441
Validation of simulated temperature profiles at rock walls in the eastern alps (Dachstein)
Authors: Schnepfleitner H. , Rode M. , Sass O.
Published: December 2017

While rock temperature is a key factor for many geomorphic phenomena in high mountains, assessing the small‐scale temperature distribution remains challenging. We adapted the program package WUFI®, originally designed to calculate energy and moisture fluxes in building walls, for modeling natural rock faces. We determined physical rock properties and local meteorological parameters as input data for the simulations at rock walls in the Dachstein Mountains, Austria, and calculated annual temperature fluctuations at the surface and at 3, 10, 30, 50 and 100 cm depth, including different elevations, aspects and slope angles. Thirty‐seven temperature sensors inserted into drillholes of different depths at ten locations (altitudes from 2300 to 2700 m) were used to validate the simulation. Additionally, surface temperatures were determined from infrared images; these were calibrated for surface emissivity using further temperature sensors. Simulated temperatures and sensor data show very good agreement, with a mean correlation coefficient of 0.94, and the validation of surface temperatures by thermal imaging also delivered good results (r > 0.9). This means that the WUFI software can be used to model complex temperature distributions in natural rock wall settings, thus making it a valuable tool for geomorphological investigations.
Exploring the effects of sparse restraints on protein structure prediction
Authors: Mandalaparthy Varun , Sanaboyana Venkata Ramana , Rafalia Hitesh , Gosavi Shachi
Published: December 2017

One of the main barriers to accurate computational protein structure prediction is searching the vast space of protein conformations. Distance restraints or inter‐residue contacts have been used to reduce this search space, easing the discovery of the correct folded state. It has been suggested that about 1 contact for every 12 residues may be sufficient to predict structure at fold level accuracy. Here, we use coarse‐grained structure‐based models in conjunction with molecular dynamics simulations to examine this empirical prediction. We generate sparse contact maps for 15 proteins of varying sequence lengths and topologies and find that given perfect secondary‐structural information, a small fraction of the native contact map (5%‐10%) suffices to fold proteins to their correct native states. We also find that different sparse maps are not equivalent and we make several observations about the type of maps that are successful at such structure prediction. Long range contacts are found to encode more information than shorter range ones, especially for α and αβ‐proteins. However, this distinction reduces for β‐proteins. Choosing contacts that are a consensus from successful maps gives predictive sparse maps as does choosing contacts that are well spread out over the protein structure. Additionally, the folding of proteins can also be used to choose predictive sparse maps. Overall, we conclude that structure‐based models can be used to understand the efficacy of structure‐prediction restraints and could, in future, be tuned to include specific force‐field interactions, secondary structure errors and noise in the sparse maps.
Effectiveness of water sprays in mitigating toxic releases
Authors: Mukherjee Samrat , Dharmavaram Seshu , Jaskolka Stephen
Published: December 2017

Water spray curtains are often advertised as means to mitigate the consequences of released chemicals from high pressure tanks. Spray curtain effectiveness claims by certain vendors are misleading—a curtain placed at the periphery of a tank will only scrub a puff of a release. A spray curtain that can effectively contain a consequential release will look very different and cost much more. Studies that demonstrate spray curtains to be effective assume low gas velocities. However, calculations show that pressurized liquid NH3 or HF when released from an orifice to the atmosphere comes out at a high velocity and momentum in the form of a two‐phase jet. The jet must travel quite a distance before the velocity drops enough to be effectively scrubbed by a water curtain. The water curtain therefore needs to be at this large distance and consequently the diameter of the water curtain manifold ring needs to be quite large to be effective. This paper presents engineering calculations to estimate jet velocity, diameter & concentration, calculations to evaluate the efficiency of water sprays and discussion of water spray curtain designs that are more effective. © 2017 American Institute of Chemical Engineers Process Saf Prog 37: 256–262, 2018
Evolution of the classification of flammable and combustible liquids in Russia
Authors: Alexeev Sergey , Smirnov Vitaly , Barbin Nicolay , Alexeeva Dar'ya
Published: December 2017

Classification of liquids on the basis of the fire and explosion characteristics plays an important role to ensure fire safety. The history of this classification is closely connected with oil revolution that took place in the second half of the 19th century in USA. Cheap kerosene led to the beginning of kerosene era. The increase of fires and explosions was the by‐effect of that process and became a real problem for a lot of countries. For safe kerosene in Russia, the first limits were set in 1886 and 1889 by the decree of the Russian Emperor Alexander III. In the future, this classification has been extended to all liquids. The first Soviet classification appeared in 1939. After the World War II, it has been further developed. Now in Russia there are several classifications of flammable and combustible liquids, in which there is the ideology of the criteria of safe kerosene. © 2017 American Institute of Chemical Engineers Process Saf Prog 37: 230–236, 2018
Effects of external radiation heat flux on combustion characteristics of pure and oil‐impregnated transformer insulating paperboard
Authors: Zhang Jiaqing , Zhang Bosi , Fan Minghao , Wang Liufang , Ding Guocheng , Tian Yu , Chen Qingtao
Published: December 2017

The effects of external radiation heat flux on the combustion characteristics of pure transformer insulating paperboard (PTIP) and oil‐impregnated transformer insulating paperboard (OITIP) were investigated experimentally. The experiments were conducted with the cone calorimeter using five external radiation heat fluxes that ranged from 25 to 80 kW/m2. The results showed that the ignition time decreased with the external radiation heat flux, and the ignition time of PTIP was much longer than that of OITIP. Both the PTIP and OITIP are thermal thick materials, and the critical radiation heat flux of the PTIP was larger than that of the OITIP. For the PTIP, the peak of the heat release rate (HRR) and toxic gas productions had no significant difference, while those of the OITIP increased with the external radiation heat flux. The HRR peak of the PTIP was larger than that of the OITIP with the external radiation heat fluxes of 25, 35, 50, and 65 kW/m2. When the radiation heat flux increased to 80 kW/m2, the HRR peak of the OITIP became higher. From the perspective of the CO production rate, the hazard of PTIP fires was more severe than that of OITIP fires under the external radiation heat fluxes of 25 and 35 kW/m2. The CO production rate of the PITP was lower than that of the OITP with the high external radiation heat fluxes of 50, 65 and 80 kW/m2. © 2017 American Institute of Chemical Engineers Process Process Saf Prog 37:362–368, 2018
Cucurbitacin B acts a potential insect growth regulator by antagonizing 20‐hydroxyecdysone activity
Authors: Zou Chuanshan , Liu Guifen , Liu Suning , Liu Shumin , Song Qisheng , Wang Jian , Feng Qili , Su Yunlin , Li Sheng
Published: December 2017

BACKGROUND

20‐Hydroxyecdysone (20E), a crucial insect steroid hormone, can bind to its cognate nuclear receptor composed of ecdysone receptor (EcR) and ultraspiracle (USP) to activate expression of 20E‐response genes, enabling subsequent metamorphosis. In this study, we tried to find out which steroid‐like compounds can block insect metamorphosis effectively and provide useful information for biopesticide study. For this purpose, we screened 126 steroid‐like compounds for possible 20E antagonists using a dual‐luciferase reporter assay with Drosophila melanogaster Kc and Bombyx mori Bm12 cells.

RESULTS

Among 126 steroid‐like compounds, three cucurbitacins (CucB, D and E) were identified as 20E antagonists in both Kc and Bm12 cells. Notably, CucB caused significant molting defects and mortality in both B. mori and D. melanogaster larvae, and dramatically hindered larval growth of Helicoverpa armigera by its anti‐feeding activity.

CONCLUSION

In vivo and in vitro experiments demonstrate that CucB acts as a potential insect growth regulator by antagonizing 20E activity and thus blocking molting and metamorphosis induced by 20E signaling. © 2017 Society of Chemical Industry
Advocating a need for suitable breeding approaches to boost integrated pest management: a European perspective
Authors: Lamichhane Jay Ram , Arseniuk Edward , Boonekamp Piet , Czembor Jerzy , Decroocq Veronique , Enjalbert Jérome , Finckh Maria R , Korbin Małgorzata , Koppel Mati , Kudsk Per , Mesterhazy Akos , Sosnowska Danuta , Zimnoch‐Guzowska Ewa , Messéan Antoine
Published: December 2017

Currently, European farmers do not have access to sufficient numbers and diversity of crop species/varieties. This prevents them from designing cropping systems more resilient to abiotic and biotic stresses. Crop diversification is a key lever to reduce pest (pathogens, animal pests and weeds) pressures at all spatial levels from fields to landscapes. In this context, plant breeding should consist of: (1) increased efforts in the development of new or minor crop varieties to foster diversity in cropping systems, and (2) focus on more resilient varieties showing local adaptation. This new breeding paradigm, called here ‘breeding for integrated pest management (IPM)’, may boost IPM through the development of cultivars with tolerance or resistance to key pests, with the goal of reducing reliance on conventional pesticides. At the same time, this paradigm has legal and practical implications for future breeding programs, including those targeting sustainable agricultural systems. By putting these issues into the context, this article presents the key outcomes of a questionnaire survey and experts' views expressed during an EU workshop entitled ‘Breeding for IPM in sustainable agricultural systems’. © 2017 Society of Chemical Industry
Herbicide resistance costs: what are we actually measuring and why?
Authors: Cousens Roger D , Fournier‐Level Alexandre
Published: December 2017

Despite the considerable research efforts invested over the years to measure the fitness costs of herbicide resistance, these have rarely been used to inform a predictive theory about the fate of resistance once the herbicide is discontinued. One reason for this may be the reductive focus on relative fitness of two genotypes as a single measure of differential performance. Although the extent of variation in relative fitness between resistant and susceptible plants has not been assessed consistently, we know enough about plant physiology and ecology not to reduce it to a single fixed value. Research must therefore consider carefully the relevance of the experimental environment, the life stage and the choice of metric when measuring fitness‐related traits. The reason most often given for measuring the cost of resistance, prediction of the impacts of management options on population dynamics, cannot be addressed using arbitrary components of fitness or a fixed value of relative fitness. To inform management options, the measurement of traits that capture the relevant processes and the main causes of their variation are required. With an emphasis on the benefit of field experiments measured over multiple time points and seasons, we highlight examples of studies that have made significant advances in this direction. © 2017 Society of Chemical Industry
Contrasting patterns of variation in weedy traits and unique crop features in divergent populations of US weedy rice (Oryza sativa sp.) in Arkansas and California
Authors: Kanapeckas Kimberly L , Tseng Te‐Ming , Vigueira Cynthia C , Ortiz Aida , Bridges William C , Burgos Nilda R , Fischer Albert J , Lawton‐Rauh Amy
Published: December 2017

BACKGROUND

Weed evolution from crops involves changes in key traits, but it is unclear how genetic and phenotypic variation contribute to weed diversification and productivity. Weedy rice is a conspecific weed of rice (Oryza sativa) worldwide. We used principal component analysis and hierarchical clustering to understand how morphologically and evolutionarily distinct US weedy rice populations persist in rice fields in different locations under contrasting management regimes. Further, we used a representative subset of 15 sequence‐tagged site fragments of expressed genes from global Oryza to assess genome‐wide sequence variation among populations.

RESULTS

Crop hull color and crop‐overlapping maturity dates plus awns, seed (panicle) shattering (> 50%), pigmented pericarp and stature variation (30.2% of total phenotypic variance) characterize genetically less diverse California weedy rice. By contrast, wild‐like hull color, seed shattering (> 50%) and stature differences (55.8% of total phenotypic variance) typify genetically diverse weedy rice ecotypes in Arkansas.

CONCLUSION

Recent de‐domestication of weedy species – such as in California weedy rice – can involve trait combinations indistinguishable from the crop. This underscores the need for strict seed certification with genetic monitoring and proactive field inspection to prevent proliferation of weedy plant types. In established populations, tillage practice may affect weed diversity and persistence over time. © 2017 Society of Chemical Industry
Characterization of Ag Schottky Barriers on Be0.02Mg0.26ZnO/ZnO Heterostructures
Authors: Ullah Md Barkat , Ding Kai , Nakagawara Tanner , Avrutin Vitaliy , Özgür Ümit , Morkoç Hadis
Published: December 2017

The BeMgZnO/ZnO heterostructures are capable of producing sufficiently high sheet electron densities to allow field effect transistor operation near or at the LO phonon plasmon resonance frequency for minimal LO phonon lifetimes and high electron velocity. Schottky barriers are imperative for the implementation of the aforementioned devices. Therefore, we have undertaken fabrication and characterization of Ag Schottky barriers on Zn‐polar Be0.02Mg0.26ZnO/ZnO heterostructures, exhibiting the said two‐dimensional electron gas (2DEG), grown by molecular beam epitaxy. Ag Schottky barriers are characterized by current–voltage (I–V) measurements in the temperature range from 80 to 400 K. At room temperature, the highest barrier height of 1.07 eV and an ideality factor of 1.22 are achieved with a rectification ratio of about eight orders of magnitude. Richardson constants of 38 ± 22 and 29 ± 20 A cm−2 K−2 are found using modified Richardson plots from Schottky diodes fabricated on two different structures. These values are consistent with the theoretical estimate of 36 A cm−2 K−2 for Be0.02Mg0.26ZnO. The temperature variation of barrier heights and ideality factors, an aberration from pure thermionic behavior, has been explained with plausible spatial inhomogeneity of barrier height with three Gaussian distributions in the temperature ranges of 80–200, 220–280, and 300–400 K.
New atomistic model of pyrrole with improved liquid state properties and structure
Authors: Macchiagodena Marina , Mancini Giordano , Pagliai Marco , Cardini Gianni , Barone Vincenzo
Published: December 2017

Structural characterization of liquid pyrrole has been obtained by performing classical molecular dynamics simulations with a new parameterization of electrostatic interactions. Despite the relatively simple molecular structure of pyrrole, a correct and accurate representation of its intermolecular interactions in bulk phase is a challenging task, since these are affected at short range by the quadrupole–quadrupole term. This new parameterization permits not only to correctly describe the liquid structure but also to obtain macroscopic properties in excellent agreement with experiments.
System for CT‐guided needle placement in the thorax and abdomen: A design for clinical acceptability, applicability and usability
Authors: Arnolli Maarten M. , Buijze Martijn , Franken Michel , de Jong Koert P. , Brouwer Dannis M. , Broeders Ivo A. M. J.
Published: December 2017

Background: Various systems exist for CT‐guided needle placement in the thorax and abdomen, but widespread adoption is lacking. The goal of this work is to develop a system for precise needle placement with a design focus on clinical acceptability, applicability and usability.

Methods: A system was outlined incorporating a needle guide on a mechanism with a remote centre of motion, manually placeable around the patient at the desired entry point and lockable by push‐button to the CT table. System and patient are scanned for system‐to‐CT registration and target specification. The needle guide is automatically aimed at the target, for manual needle insertion to specified depth.

Results: A fully functional prototype was realized, achieving 1.2±0.6 mm placement error at 79.0±8.4 mm depth and 2.1±0.7 mm at 156.0±6.9 mm for 2×12 in‐ and out‐of‐plane punctures in a gelatin phantom.

Conclusions: The system enables precise needle placement in a single insertion and is ready for its first clinical deployment.
Robotic technologies for solar‐powered UAVs: Fully autonomous updraft‐aware aerial sensing for multiday search‐and‐rescue missions
Authors: Oettershagen Philipp , Stastny Thomas , Hinzmann Timo , Rudin Konrad , Mantel Thomas , Melzer Amir , Wawrzacz Bartosz , Hitz Gregory , Siegwart Roland
Published: December 2017

Large‐scale aerial sensing missions can greatly benefit from the perpetual endurance capability provided by high‐performance low‐altitude solar‐powered unmanned aerial vehicles (UAVs). However, today these UAVs suffer from small payload capacity, low energetic margins, and high operational complexity. To tackle these problems, this paper presents four individual technical contributions and integrates them into an existing solar‐powered UAV system: First, a lightweight and power‐efficient day/night‐capable sensing system is discussed. Second, means to optimize the UAV platform to the specific payload and to thereby achieve sufficient energetic margins for day/night flight with payload are presented. Third, existing autonomous launch and landing functionality is extended for solar‐powered UAVs. Fourth, as a main contribution an extended Kalman filter (EKF)‐based autonomous thermal updraft tracking framework is developed. Its novelty is that it allows the end‐to‐end integration of the thermal‐induced roll moment into the estimation process. It is assessed against unscented Kalman filter and particle filter methods in simulation and implemented on the aircraft's low‐power autopilot. The complete system is verified during a 26 h search‐and‐rescue aerial sensing mock‐up mission that represents the first‐ever fully autonomous perpetual endurance flight of a small solar‐powered UAV with a day/night‐capable sensing payload. It also represents the first time that solar‐electric propulsion and autonomous thermal updraft tracking are combined in flight. In contrast to previous work that has focused on the energetic feasibility of perpetual flight, the individual technical contributions of this paper are considered core functionality to guarantee ease‐of‐use, effectivity, and reliability in future multiday aerial sensing operations with small solar‐powered UAVs.
Learning to detect misaligned point clouds
Authors: Almqvist Håkan , Magnusson Martin , Kucner Tomasz P. , Lilienthal Achim J.
Published: December 2017

Matching and merging overlapping point clouds is a common procedure in many applications, including mobile robotics, three‐dimensional mapping, and object visualization. However, fully automatic point‐cloud matching, without manual verification, is still not possible because no matching algorithms exist today that can provide any certain methods for detecting misaligned point clouds. In this article, we make a comparative evaluation of geometric consistency methods for classifying aligned and nonaligned point‐cloud pairs. We also propose a method that combines the results of the evaluated methods to further improve the classification of the point clouds. We compare a range of methods on two data sets from different environments related to mobile robotics and mapping. The results show that methods based on a Normal Distributions Transform representation of the point clouds perform best under the circumstances presented herein.
Description and experimental results of a panoramic K‐band radar dedicated to perception in mobile robotics applications
Authors: Rouveure Raphaël , Faure Patrice , Monod Marie‐Odile
Published: December 2017

Robust environmental perception is a crucial parameter for the development of autonomous ground vehicle applications, especially in the field of agricultural robotics which is one of the priorities for the Horizon 2020 robotics funding (EU funding program for research and innovation). Because of uncontrolled and changing environmental conditions in outdoor and natural environments, data from optical sensors classically used in mobile robotics can be compromised and unusable. In such situations, microwave radar can provide an alternative and complementary solution for perception tasks. The aim of this paper is to present PELICAN radar, a microwave radar specifically designed for mobile robotics applications, including obstacle detection, mapping, and situational awareness in general. PELICAN radar provides each second a view over 360° of the surrounding environment, from 5 m up to 100 m. A description of the technological solutions adopted for the development of PELICAN radar (hardware and software) is presented. Results obtained in various outdoor and open environments, including urban and natural areas, are also described. Sets of PELICAN radar data are made available online for researchers interested in processing this type of data.
Inverse probability weighting to control confounding in an illness‐death model for interval‐censored data
Authors: Gillaizeau Florence , Sénage Thomas , Le Borgne Florent , Le Tourneau Thierry , Roussel Jean‐Christian , Leffondrè Karen , Porcher Raphaël , Giraudeau Bruno , Dantan Etienne , Foucher Yohann
Published: December 2017

Multistate models with interval‐censored data, such as the illness‐death model, are still not used to any considerable extent in medical research regardless of the significant literature demonstrating their advantages compared to usual survival models. Possible explanations are their uncommon availability in classical statistical software or, when they are available, by the limitations related to multivariable modelling to take confounding into consideration. In this paper, we propose a strategy based on propensity scores that allows population causal effects to be estimated: the inverse probability weighting in the illness semi‐Markov model with interval‐censored data. Using simulated data, we validated the performances of the proposed approach. We also illustrated the usefulness of the method by an application aiming to evaluate the relationship between the inadequate size of an aortic bioprosthesis and its degeneration or/and patient death. We have updated the R package multistate to facilitate the future use of this method.
Analysis of the U.S. patient referral network
Authors: An Chuankai , O'Malley A. James , Rockmore Daniel N. , Stock Corey D.
Published: December 2017

In this paper, we analyze the US Patient Referral Network (also called the Shared Patient Network) and various subnetworks for the years 2009 to 2015. In these networks, two physicians are linked if a patient encounters both of them within a specified time interval, according to the data made available by the Centers for Medicare and Medicaid Services. We find power law distributions on most state‐level data as well as a core‐periphery structure. On a national and state level, we discover a so‐called small‐world structure as well as a “gravity law” of the type found in some large‐scale economic networks. Some physicians play the role of hubs for interstate referral. Strong correlations between certain network statistics with health care system statistics at both the state and national levels are discovered. The patterns in the referral network evinced using several statistical analyses involving key metrics derived from the network illustrate the potential for using network analysis to provide new insights into the health care system and opportunities or mechanisms for catalyzing improvements.
An R2‐curve for evaluating the accuracy of dynamic predictions
Authors: Fournier Marie‐Cécile , Dantan Etienne , Blanche Paul
Published: December 2017

In the context of chronic diseases, patient's health evolution is often evaluated through the study of longitudinal markers and major clinical events such as relapses or death. Dynamic predictions of such types of events may be useful to improve patients management all along their follow‐up. Dynamic predictions consist of predictions that are based on information repeatedly collected over time, such as measurements of a biomarker, and that can be updated as soon as new information becomes available. Several techniques to derive dynamic predictions have already been suggested, and computation of dynamic predictions is becoming increasingly popular.

In this work, we focus on assessing predictive accuracy of dynamic predictions and suggest that using an R2‐curve may help. It facilitates the evaluation of the predictive accuracy gain obtained when accumulating information on a patient's health profile over time. A nonparametric inverse probability of censoring weighted estimator is suggested to deal with censoring. Large sample results are provided, and methods to compute confidence intervals and bands are derived. A simulation study assesses the finite sample size behavior of the inference procedures and illustrates the shape of some R2‐curves which can be expected in common settings. A detailed application to kidney transplant data is also presented.
In Situ Probing of the Particle‐Mediated Mechanism of WO3‐Networked Structures Grown inside Confined Mesoporous Channels
Authors: Zhang Lingling , Li Jiang , You Hongjun , Ma Chuansheng , Lan Si , Wu Zhenduo , Zeng Jianrong , Tian Feng , Fang Jixiang
Published: December 2017

Nanocasting, using ordered mesoporous silica or carbon as a hard template, has enormous potential for preparing novel mesoporous materials with new structures and compositions. Although a variety of mesoporous materials have been synthesized in recent years, the growth mechanism of nanostructures in a confined space, such as mesoporous channels, is not well understood, which hampers the controlled synthesis and further application of mesoporous materials. Here, the nucleation and growth of WO3‐networked mesostructures within an ordered mesoporous matrix, using an in situ transmission electron microscopy heating technique and in situ synchrotron small‐angle X‐ray scattering spectroscopy, are probed. It is found that the formation of WO3 mesostructures involves a particle‐mediated transformation and coalescence mechanism. The liquid‐like particle‐mediated aggregation and mesoscale transformation process can occur in ≈10 nm confined mesoporous channels, which is completely unexpected. The detailed mechanistic study will be of great help for experimental design and to exploit a variety of mesoporous materials for diverse applications, such as catalysis, absorption, separation, energy storage, biomedicine, and nanooptics.