bluuebunny/crossref_metadata_2025 huggingface dataset:
03.09: Performance assessment and design methodology of free from damage moment resisting frames
Authors: Zimbru Mariana , D'Aniello Mario , Cabrera Eliana Inca , Landolfo Raffaele , De Martino Attilio
Published: September 2017

The seismic design strategy implemented in current codes is based on the capacity design principle that allows the formation of plastic hinges into predefined parts of the structure. Therefore, significant damage is expected at ultimate limit state, to which high repair costs are associated.

Recently, new design strategies have been proposed in order to avoid the damage of the structure. The most of them are grouped into two categories, namely i) using special damping devices introduced in the structure as additional resisting element; ii) changing the dissipation mechanism of the structure by means of friction‐based dissipative joints. The second possibility is really promising and effective because it guarantees low forces transferred to the foundations and no architectural interference, if adopted for moment‐resisting frames (MRFs).

The novelty of free from damage joints lays in the fact that the energy is dissipated by friction at the interface between plates in contact instead of the classical plastic deformation energy dissipation mechanism.

The performance of MRFs equipped with free from damage joints differs from that of conventional MRFs. This implies the need to update the current EC8 rules to free from damage MRFs. Therefore, in this paper new design criteria have been proposed. The effectiveness of the new rules has been verified by means of a comprehensive set of numerical analyses, by comparing the seismic performance of two sets of frames having geometrical configurations that are typical for current European practice: a set of traditional MRF structures (EC8 compliant) and another set of MRFs equipped with friction joints.
03.11: Experimental investigation of the creep effect on prestressed bolts used in innovative friction connections
Authors: D'Antimo Marina , Demonceau Jean‐François , Latour Massimo , Rizzano Gianvittorio , Jaspart Jean‐Pierre
Published: September 2017

In the framework of a RFCS project entitled “FREEDAM ‐Free From Damage Connections”, innovative friction connections activated as dissipative zones in case of seismic actions are studied, with the objective to avoid any damage in the structures not only for frequent and occasional seismic events, but also for destructive earthquakes. These friction connections are made of stainless steel plates with specific coatings fastened with preloaded bolts placed in long slotted holes allowing significant displacement of the plates when the friction resistance is reached and so allowing significant dissipation of energy.

As a partner of this project, The University of Liege is in charge of proposing analytical design procedures for these innovative joints and in particular of investigating the evolution of the prestressing in the bolts according to time, a key parameter when it is intended to dissipate energy through the activation of friction.

This paper presents first preliminary results obtained through long term tests (5 months) performed on steel plates with particular coatings fastened with M20 Bolts. The main parameters registered during these tests were the relative displacements between the connected plates and the evolution of the prestressing in the bolts. The tests were performed according to EN 1090‐2, in order to assess the loss of preloading over time and the creep of the plate. The final objective of the conducted studies is to propose a methodology to predict the prestressing loss in order to ensure that a minimum level of prestressing is kept over the full life of the structures, i.e. at least 50 years.
Effect of nitrogen doping on reactivity of coal char in reducing NO
Authors: Wang Xin , Gao Jianmin , Sun Zhihao , Cheng Jian , Xu Li , Du Qian , Qin Yukun
Published: September 2017

Mixing coal char into coal powder and enhancing its reactivity with NO in the combustion process of a layer burning furnace is an effective method to realize low‐cost resource reduction of NOx. To enhance NO reducibility of char at high temperatures, this study used Shuozhou bituminous coal to prepare different nitriding chars (char modified by nitrogen doping) by changing the nitrogen agent, the dosage of nitrogen agent, and the treatment method. The effects of different nitriding conditions on the NO reducibility of char were evaluated using a programmed temperature rising method. The results show that NO reducibility of char is improved in different degrees after nitriding treatment, which is related to the improvement of pore structure and the formation of nitrogen‐containing functional groups. The NO reducibility of char is enhanced in the high‐temperature region when increasing the dosage of urea, but excessive urea amounts can hinder the porosity development of char, resulting in the decline of NO reduction efficiency. Ammonium bicarbonate as a nitrogen agent shows better effects on NO reduction below 725 °C compared with urea, but weaker effects above 725 °C. Furthermore, heat treatment can weaken the effect of nitrogen doping, but the overall trend of NO reduction curve is almost unchanged.
Using the PRIDE Database and ProteomeXchange for Submitting and Accessing Public Proteomics Datasets
Authors: Jarnuczak Andrew F. , Vizcaíno Juan Antonio
Published: September 2017

The ProteomeXchange (PX) Consortium is the unifying framework for world‐leading mass spectrometry (MS)–based proteomics repositories. Current members include the PRIDE database (U.K.), PeptideAtlas/PASSEL, and MassIVE (U.S.A.), and jPOST (Japan). The Consortium standardizes submission and dissemination of public proteomics data worldwide. This is achieved through implementing common data submission guidelines and enforcing metadata requirements by each of the members. Furthermore, the members use a common identifier space. Each dataset receives a unique (PXD) accession number and is publicly accessible as soon as the associated scientific publications are released. The two basic protocols provide a step‐by‐step guide on how to submit data to the PRIDE database, and describe how to access the PX portal (called ProteomeCentral), which can be used to search datasets available in any of the PX members. © 2017 by John Wiley & Sons, Inc.
Survey design for precise fire management conservation targets
Authors: Sitters Holly , Di Stefano Julian , Wills Timothy , Swan Matthew , York Alan
Published: September 2017

Common goals of ecological fire management are to sustain biodiversity and minimize extinction risk. A novel approach to achieving these goals determines the relative proportions of vegetation growth stages (equivalent to successional stages, which are categorical representations of time since fire) that maximize a biodiversity index. The method combines data describing species abundances in each growth stage with numerical optimization to define an optimal growth‐stage structure that provides a conservation‐based operational target for managers. However, conservation targets derived from growth‐stage optimization are likely to depend critically on choices regarding input data. There is growing interest in the use of growth‐stage optimization as a basis for fire management, thus understanding of how input data influence the outputs is crucial. Simulated data sets provide a flexible platform for systematically varying aspects of survey design and species inclusions. We used artificial data with known properties, and a case‐study data set from southeastern Australia, to examine the influence of (1) survey design (total number of sites and their distribution among growth stages) and (2) species inclusions (total number of species and their level of specialization) on the precision of conservation targets. Based on our findings, we recommend that survey designs for precise estimates would ideally involve at least 80 sites, and include at least 80 species. Greater numbers of sites and species will yield increasingly reliable results, but fewer might be sufficient in some circumstances. An even distribution of sites among growth stages was less important than the total number of sites, and omission of species is unlikely to have a major influence on results as long as several species specialize on each growth stage. We highlight the importance of examining the responses of individual species to growth stage before feeding survey data into the growth‐stage optimization black box, and advocate use of a resampling procedure to determine the precision of results. Collectively, our findings form a reproducible guide to designing ecological surveys that yield precise conservation targets through growth‐stage optimization, and ultimately help sustain biodiversity in fire‐prone systems.
Human–animal agency in reindeer management: Sámi herders’ perspectives on vegetation dynamics under climate change
Authors: Horstkotte T. , Utsi T. Aa. , Larsson‐Blind Å. , Burgess P. , Johansen B. , Käyhkö J. , Oksanen L. , Forbes B. C.
Published: September 2017

Many primary livelihoods in Arctic and sub‐Arctic regions experience accelerating effects of environmental change. The often close connection between indigenous peoples and their respective territories allows them to make detailed observations of how these changes transform the landscapes where they practice their daily activities. Here, we report Sámi reindeer herders’ observations based on their long‐term inhabitance and use of contrasting pastoral landscapes in northern Fennoscandia. In particular, we focus on the capacity for various herd management regimes to prevent a potential transformation of open tundra vegetation to shrubland or woodland. Sámi herders did not confirm a substantial, rapid, or large‐scale transformation of treeless tundra areas into shrub‐ and/or woodlands. However, where they observe encroachment of open tundra landscapes, a range of factors was deemed responsible. These included abiotic conditions, anthropogenic influences, and the direct and indirect effects of reindeer. The advance of the mountain birch tree line was in some cases associated with reduced or discontinued grazing and firewood cutting, depending on the seasonal significance of these particular areas. Where the tree line has risen in elevation and/or latitude, herding practices have by necessity adapted to these changes. Exploiting the capacity of reindeer impacts on vegetation as a conservation tool offers time‐tested adaptive strategies of ecosystem management to counteract a potential encroachment of the tundra by woody plants. However, novel solutions in environmental governance involve difficult trade‐offs for ecologically sustainable, economically viable, and socially desirable management strategies.
Improving the use of early timber inventories in reconstructing historical dry forests and fire in the western United States
Authors: Baker William L. , Hanson Chad T.
Published: September 2017

Early timber inventories in dry forests of the western United States offer detailed data sets that might provide historical information to guide restoration and preparation for future forests, but inventories have errors, biases, and limitations. We reviewed early documentation of errors and estimated errors by comparing inventory estimates to nearby tree‐ring and plot estimates. In a case study in the Greenhorn Mountains, southern Sierra Nevada, California, we studied how selection and use of evidence affects findings and compared timber‐inventory, land‐survey, and other early evidence about historical forests and fire. Early documents showed inventories were unreliable, often with large underestimation errors from poor visual estimates, requiring correction multipliers of 2.0–2.5. Comparing inventory estimates to tree‐ring estimates, we found commonly used two‐chain‐wide inventories required correction multipliers of about 1.4–3.2, consistent with, but wider than the 2.0–2.5 range. These needed corrections were not applied in any study. The case study showed (1) tree‐density estimates from narrower one‐chain‐wide inventories could be more accurate, (2) data are often available, but unused, that provide quantitative evidence about historical high‐severity fires consistent with nearby historical reports, and (3) differences in forest structure between inventories and land surveys may be explained by tree growth, stand development, and especially a significant fire. Our review also documented biased placement of inventories in merchantable timber, often excluding younger forests, chaparral, and other indicators of preceding mixed/high‐severity fires. We found added significant bias introduced by omitting areas burned in mixed/high‐severity fires, or by missing evidence of these fires on parts of forms or associated archival materials. Use of early timber inventories could be improved by (1) avoiding use of unreliable two‐chain‐wide inventories or applying correction multipliers to inventory estimates, (2) completing an accuracy test of one‐chain‐wide inventories, (3) locating and using notes, maps, and other data about small trees and high‐severity fires often available in inventory archives, or omitting conclusions about these, (4) deriving an envelope model of inference space for inventories, and (5) specifying a large area, then including all available inventory data within it, or using unbiased selection criteria. These improvements could help bring timber‐inventory data into congruence with other historical sources.
Quantity and quality limit detritivore growth: mechanisms revealed by ecological stoichiometry and co‐limitation theory
Authors: Halvorson Halvor M. , Sperfeld Erik , Evans‐White Michelle A.
Published: September 2017

Resource quantity and quality are fundamental bottom‐up constraints on consumers. Best understood in autotroph‐based systems, co‐occurrence of these constraints may be common but remains poorly studied in detrital‐based systems. Here, we used a laboratory growth experiment to test limitation of the detritivorous caddisfly larvae Pycnopsyche lepida across a concurrent gradient of oak litter quantity (food supply) and quality (phosphorus : carbon [P:C ratios]). Growth increased simultaneously with quantity and quality, indicating co‐limitation across the resource gradients. We merged approaches of ecological stoichiometry and co‐limitation theory, showing how co‐limitation reflected shifts in C and P acquisition throughout homeostatic regulation. Increased growth was best explained by elevated consumption rates and improved P assimilation, which both increased with elevated quantity and quality. Notably, C assimilation efficiencies remained unchanged and achieved maximum 18% at low quantity despite pronounced C limitation. Detrital C recalcitrance and substantive post‐assimilatory C losses probably set a minimum quantity threshold to achieve positive C balance. Above this threshold, greater quality enhanced larval growth probably by improving P assimilation toward P‐intensive growth. We suggest this interplay of C and P acquisition contributes to detritivore co‐limitation, highlighting quantity and quality as potential simultaneous bottom‐up controls in detrital‐based ecosystems, including under anthropogenic change like nutrient enrichment.
Sustainable Design for the Direct Fabrication and Highly Versatile Functionalization of Nanocelluloses
Authors: Afewerki Samson , Alimohammadzadeh Rana , Osong Sinke H. , Tai Cheuk‐Wai , Engstrand Per , Córdova Armando
Published: September 2017

This study describes a novel sustainable concept for the scalable direct fabrication and functionalization of nanocellulose from wood pulp with reduced energy consumption. A central concept is the use of metal‐free small organic molecules as mediators and catalysts for the production and subsequent versatile surface engineering of the cellulosic nanomaterials via organocatalysis and click chemistry. Here, “organoclick” chemistry enables the selective functionalization of nanocelluloses with different organic molecules as well as the binding of palladium ions or nanoparticles. The nanocellulosic material is also shown to function as a sustainable support for heterogeneous catalysis in modern organic synthesis (e.g., Suzuki cross‐coupling transformations in water). The reported strategy not only addresses obstacles and challenges for the future utilization of nanocellulose (e.g., low moisture resistance, the need for green chemistry, and energy‐intensive production) but also enables new applications for nanocellulosic materials in different areas.
Hydrogen‐Atom Transfer Oxidation with H2O2 Catalyzed by [FeII(1,2‐bis(2,2′‐bipyridyl‐6‐yl)ethane(H2O)2]2+: Likely Involvement of a (μ‐Hydroxo)(μ‐1,2‐peroxo)diiron(III) Intermediate
Authors: Khenkin Alexander M. , Vedichi Madhu , Shimon Linda J. W. , Cranswick Matthew A. , Klein Johannes E. M. N. , Que Lawrence , Neumann Ronny
Published: September 2017

The iron(II) triflate complex (1) of 1,2‐bis(2,2′‐bipyridyl‐6‐yl)ethane, with two bipyridine moieties connected by an ethane bridge, was prepared. Addition of aqueous 30 % H2O2 to an acetonitrile solution of 1 yielded 2, a green compound with λmax=710 nm. Moessbauer measurements on 2 showed a doublet with an isomer shift (δ) of 0.35 mm/s and a quadrupole splitting (ΔEQ) of 0.86 mm/s, indicative of an antiferromagnetically coupled diferric complex. Resonance Raman spectra showed peaks at 883, 556 and 451 cm−1 that downshifted to 832, 540 and 441 cm−1 when 1 was treated with H218O2. All the spectroscopic data support the initial formation of a (μ‐hydroxo)(μ‐1,2‐peroxo)diiron(III) complex that oxidizes carbon‐hydrogen bonds. At 0 °C 2 reacted with cyclohexene to yield allylic oxidation products but not epoxide. Weak benzylic C−H bonds of alkylarenes were also oxidized. A plot of the logarithms of the second order rate constants versus the bond dissociation energies of the cleaved C−H bond showed an excellent linear correlation. Along with the observation that oxidation of the probe substrate 2,2‐dimethyl‐1‐phenylpropan‐1‐ol yielded the corresponding ketone but no benzaldehyde, and the kinetic isotope effect, kH/kD, of 2.8 found for the oxidation of xanthene, the results support the hypothesis for a metal‐based H‐atom abstraction mechanism. Complex 2 is a rare example of a (μ‐hydroxo)(μ‐1,2‐peroxo)diiron(III) complex that can elicit the oxidation of carbon‐hydrogen bonds.
Evaluating increased effort for item disposal to improve recycling at a university
Authors: Fritz Jennifer N. , Dupuis Danielle L. , Wu Wai‐Ling , Neal Ashley E. , Rettig Lisa A. , Lastrapes Renée E.
Published: September 2017

An evaluation of increased response effort to dispose of items was conducted to improve recycling at a university. Signs prompting individuals to recycle and notifying them of the location of trash and recycling receptacles were posted in each phase. During the intervention, trashcans were removed from the classrooms, and one large trashcan was available in the hallway next to the recycling receptacles. Results showed that correct recycling increased, and trash left in classrooms increased initially during the second intervention phase before returning to baseline levels.
Safety and efficacy of hydroxyapatite scaffold in the prevention of jaw osteonecrosis in vivo
Authors: de Almeida Adriana Duarte , Leite Fernanda Gomes , Chaud Marco Vinícius , Rebelo Márcia de Araújo , Borges Liliane Cristine Ferreira de Souza , Viroel Fabia Judice Marques , Hataka Alessandre , Grotto Denise
Published: September 2017

Two scaffolds of chitosan/sodium alginate/hydroxyapatite (Ch/NaAlg/Hap) 1:1:0.2 and 1:1:0.6 were evaluated in the prevention of bisphosphonate‐induced jaw osteonecrosis. Two groups of rats (n = 24, according to the euthanasia time: 15 or 30 days after the last Zoledronic acid (ZA) administration) were subdivided in four subgroups (n = 6): I – Control (saline + teeth extraction); II – ZA 0.6 mg/kg + teeth extraction; III – ZA + teeth extraction + scaffold 1:1:0.2; IV – ZA + teeth extraction + scaffold 1:1:0.6. Jaws were evaluated histologically and blood was evaluated for hematological and biochemical parameters. Histopathology showed significant osteonecrosis in AZ group. The scaffold's implantation, despite the inflammatory process, were able to prevent the osteonecrosis. In the 15‐day euthanasia group, an increase in red blood cells and platelets was observed in the subgroup II. Hemoglobin and hematocrit decreased in subgroup IV compared to II. Hepatic transaminases and creatinine concentration increased significantly in subgroup II. Calcium concentration increased in subgroup IV compared to II. In the 30‐day euthanasia group, no differences among the groups were observed for any parameter. Scaffolds proved to be efficient and safe to liver and kidney function. Some hematological parameters were altered by the scaffold, but returned to normal concentrations over time. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1799–1808, 2018.
Twofold triple systems with cyclic 2‐intersecting Gray codes
Authors: Erzurumluoğlu Aras , Pike David A.
Published: September 2017

Given a combinatorial design with block set , the block‐intersection graph (BIG) of is the graph that has as its vertex set, where two vertices and are adjacent if and only if . The i‐block‐intersection graph (i‐BIG) of is the graph that has as its vertex set, where two vertices and are adjacent if and only if . In this paper, several constructions are obtained that start with twofold triple systems (TTSs) with Hamiltonian 2‐BIGs and result in larger TTSs that also have Hamiltonian 2‐BIGs. These constructions collectively enable us to determine the complete spectrum of TTSs with Hamiltonian 2‐BIGs (equivalently TTSs with cyclic 2‐intersecting Gray codes) as well as the complete spectrum for TTSs with 2‐BIGs that have Hamilton paths (i.e. for TTSs with 2‐intersecting Gray codes). In order to prove these spectrum results, we sometimes require ingredient TTSs that have large partial parallel classes; we prove lower bounds on the sizes of partial parallel classes in arbitrary TTSs, and then construct larger TTSs with both cyclic 2‐intersecting Gray codes and parallel classes.
Synthesis and Antimicrobial Activity of Novel Azolopyrimidines and Pyrido‐Triazolo‐Pyrimidinones Incorporating Pyrazole Moiety
Authors: Abbas Ikhlass M. , Abdallah Magda A. , Gomha Sobhi M. , Kazem Mariam S. H.
Published: September 2017

A new series of azolopyrimidine derivatives incorporating pyrazole moiety were synthesized by reaction of 1‐(pyrazol‐3‐yl)‐2‐propenone with a number of heterocyclic amines in the presence of a catalytic amount of acetic acid. The mechanism of formation of the products was also discussed, and the structure assigned was elucidated based on both elemental and spectral analyses data. In addition, 7‐(pyrazolyl)‐2‐thioxo‐5‐phenyl‐1,3‐dihydropyrido[2,3‐d]pyrimidin‐4‐one was used as starting material for preparation of a new series of pyridotriazolopyrimidines via its reaction with a variety of hydrazonoyl chlorides in dioxane using triethylamines as catalyst. The assigned structure for these products was also proved via elemental analysis and spectroscopic techniques (IR, 1H NMR, and Mass). Moreover, the antimicrobial activity of some selected examples of the new products was evaluated, and the results obtained revealed high activity of compound 20a against the Gram positive bacteria Staphylococcus aureus and the Gram negative bacteria Klebsiella pneumonie. All the tested compounds have no antifungal activity.
Consistency‐based respiratory motion estimation in rotational angiography
Authors: Unberath Mathias , Aichert André , Achenbach Stephan , Maier Andreas
Published: September 2017

Purpose

Rotational coronary angiography enables 3D reconstruction but suffers from intra‐scan cardiac and respiratory motion. While gating handles cardiac motion, respiratory motion requires compensation. State‐of‐the‐art algorithms rely on 3D‐2D registration that depends on initial reconstructions of sufficient quality. We propose a compensation method that is applied directly in projection domain. It overcomes the need for reconstruction and thus complements the state‐of‐the‐art.

Methods

Virtual single‐frame background subtraction based on vessel segmentation and spectral deconvolution yields non‐truncated images of the contrasted lumen. This allows motion compensation based on data consistency conditions. We compensate craniocaudal shifts by optimizing epipolar consistency to (a) devise an image‐based surrogate for cardiac motion and (b) compensate for respiratory motion. We validate our approach in two numerical phantom studies and three clinical cases.

Results

Correlation of the image‐based surrogate for cardiac motion with the ECG‐based ground truth was excellent yielding a Pearson correlation of 0.93 ± 0.04. Considering motion compensation, the target error measure decreased by 98% and 69%, respectively, for the phantom experiments while for the clinical cases the same figure of merit improved by 46 ± 21%.

Conclusions

The proposed method is entirely image‐based and accurately estimates craniocaudal shifts due to respiration and cardiac contraction. Future work will investigate experimental trajectories and possibilities for simplification of the single‐frame subtraction pipeline.
Technical Note: A model‐based sinogram correction for beam hardening artifact reduction in CT
Authors: Lee Sung Min , Seo Jin Keun , Chung Yong Eun , Baek Jongduk , Park Hyoung Suk
Published: September 2017

Purpose

This study aims to propose a physics‐based method of reducing beam‐hardening artifacts induced by high‐attenuation materials such as metal stents or other metallic implants.

Methods

The proposed approach consists of deriving a sinogram inconsistency formula representing the energy dependence of the attenuation coefficient of high‐attenuation materials. This inconsistency formula more accurately represents the inconsistencies of the sinogram than that of a previously reported formula (called the MAC‐BC method). This is achieved by considering the properties of the high‐attenuation materials, which include the materials’ shapes and locations and their effects on the incident X‐ray spectrum, including their attenuation coefficients.

Results

Numerical simulation and phantom experiment demonstrate that the modeling error of MAC‐BC method are nearly completely removed by means of the proposed method.

Conclusion

The proposed method reduces beam‐hardening artifacts arising from high‐attenuation materials by relaxing the assumptions of the MAC‐BC method. In doing so, it outperforms the original MAC‐BC method. Further research is required to address other potential sources of metal artifacts, such as photon starvation, scattering, and noise.
Objective comparison of high‐contrast spatial resolution and low‐contrast detectability for various clinical protocols on multiple CT scanners
Authors: Racine Damien , Viry Anaïs , Becce Fabio , Schmidt Sabine , Ba Alexandre , Bochud François O. , Edyvean Sue , Schegerer Alexander , Verdun Francis R.
Published: September 2017

Purpose

We sought to compare objectively computed tomography (CT) scanner performance for three clinically relevant protocols using a task‐based image quality assessment method in order to assess the potential for radiation dose reduction.

Methods

Four CT scanners released between 2003 and 2007 by different manufacturers were compared with four CT scanners released between 2012 and 2014 by the same manufacturers using ideal linear model observers (MO): prewhitening (PW) MO and channelized Hotelling (CHO) MO with Laguerre‐Gauss channels for high‐contrast spatial resolution and low‐contrast detectability (LCD) performance, respectively. High‐contrast spatial resolution was assessed using a custom‐made phantom that enabled the computation of the target transfer function (TTF) and noise power spectrum (NPS). Low‐contrast detectability was assessed using a commercially available anthropomorphic abdominal phantom providing equivalent diameters of 24, 29.6, and 34.6 cm. Three protocols were reviewed: a head (trauma) and an abdominal (urinary stones) protocol were applied to assess high‐contrast spatial resolution performance; and another abdominal (focal liver lesions) protocol was applied for LCD. The liver protocol was tested using fixed and modulated tube currents. The PW MO was proposed for assessing high‐contrast detectability performance of the various CT scanners.

Results

Compared with older generation CT scanners, three newer systems displayed significant improvements in high‐contrast detectability over that of their predecessors. A fourth, newer system had lower performance. The CHO MO was appropriate for assessing LCD performance and revealed that an excellent level of image quality could be obtained with newer scanners at significantly lower dose levels.

Conclusions

This study shows that MO can objectively benchmark CT scanners using a task‐based image quality method, thus helping to estimate the potential for further dose reductions offered by the latest systems. Such an approach may be useful for adequately and quantitatively comparing clinically relevant image quality among various scanners.
Investigating simulation‐based metrics for characterizing linear iterative reconstruction in digital breast tomosynthesis
Authors: Rose Sean D. , Sanchez Adrian A. , Sidky Emil Y. , Pan Xiaochuan
Published: September 2017

Purpose

Simulation‐based image quality metrics are adapted and investigated for characterizing the parameter dependences of linear iterative image reconstruction for DBT.

Methods

Three metrics based on a 2D DBT simulation are investigated: (1) a root‐mean‐square‐error (RMSE) between the test phantom and reconstructed image, (2) a gradient RMSE where the comparison is made after taking a spatial gradient of both image and phantom, and (3) a region‐of‐interest (ROI) Hotelling observer (HO) for signal‐known‐exactly/background‐known‐exactly (SKE/BKE) and signal‐known‐exactly/background‐known‐statistically (SKE/BKS) detection tasks. Two simulation studies are performed using the aforementioned metrics, varying voxel aspect ratio, and regularization strength for two types of Tikhonov‐regularized least‐squares optimization. The RMSE metrics are applied to a 2D test phantom with resolution bar patterns at varying angles, and the ROI‐HO metric is applied to two tasks relevant to DBT: lesion detection, modeled by use of a large, low‐contrast signal, and microcalcification detection, modeled by use of a small, high‐contrast signal. The RMSE metric trends are compared with visual assessment of the reconstructed bar‐pattern phantom. The ROI‐HO metric trends are compared with 3D reconstructed images from ACR phantom data acquired with a Hologic Selenia Dimensions DBT system.

Results

Sensitivity of the image RMSE to mean pixel value is found to limit its applicability to the assessment of DBT image reconstruction. The image gradient RMSE is insensitive to mean pixel value and appears to track better with subjective visualization of the reconstructed bar‐pattern phantom. The ROI‐HO metric shows an increasing trend with regularization strength for both forms of Tikhonov‐regularized least‐squares; however, this metric saturates at intermediate regularization strength indicating a point of diminishing returns for signal detection. Visualization with the reconstructed ACR phantom images appear to show a similar dependence with regularization strength.

Conclusions

From the limited studies presented it appears that image gradient RMSE trends correspond with visual assessment better than image RMSE for DBT image reconstruction. The ROI‐HO metric for both detection tasks also appears to reflect visual trends in the ACR phantom reconstructions as a function of regularization strength. We point out, however, that the true utility of these metrics can only be assessed after amassing more data.
Polypyrrole‐CoFe2O4 nanocomposites: Polymer influence on magnetic behavior and particle effects on polymer conduction
Authors: Muñoz Resta Ignacio , Sellés José M. , Lanús‐Méndez‐Elizalde Matías , Antonel Paula S. , Molina Fernando V.
Published: September 2017

Composites of cobalt ferrite nanoparticles in a polypyrrole (PPy) matrix have been synthesized in acid media and characterized by X‐ray diffraction studies, scanning and transmission electron microscopy observation, thermogravimetric analysis, conductivity, and infrared spectroscopy measurements. Two types of composites were prepared: one including dodecylbenzenesulphonic acid as a particle protector and another one without protection. The magnetic behavior was studied through DC magnetization measurements; hysteresis loops were observed, showing ferromagnetic behavior for particles and composites. Materials with particle protection showed magnetic parameters independent of the PPy/ferrite ratio; in the absence of protector, both the coercivity and remanence ratio decreased as the PPy/ferrite ratio increased. These results are attributed to conducting polymer effects on the ferrite particles, affecting the magnetic anisotropy. On the other hand, composites with low PPy/ferrite ratio showed positive magnetoresistance of up to 20% at room temperature, indicating an effect of the magnetic particles on polymer conduction. POLYM. COMPOS., 39:4617–4627, 2018. © 2017 Society of Plastics Engineers
Forty years of collaborative computational crystallography
Authors: Agirre Jon , Dodson Eleanor
Published: September 2017

A brief overview is provided of the history of collaborative computational crystallography, with an emphasis on the Collaborative Computational Project No. 4. The key steps in its development are outlined, with consideration also given to the underlying reasons which contributed, and ultimately led to, the unprecedented success of this venture.
Investigation of the Self‐Doping Process in HgSe Nanocrystals
Authors: Livache Clément , Martinez Bertille , Robin Adrien , Goubet Nicolas , Dubertret Benoit , Wang Hongyue , Ithurria Sandrine , Aubin Hervé , Lhuillier Emmanuel
Published: September 2017

Colloidal nanocrystals are an interesting platform for the design of low cost infrared optoelectronic materials. In addition to the conventionally observed interband features, doped nanocrystals present intraband transitions, which expand the possibilities for electronic spectrum engineering. In this paper, the recent results obtained in the field of mercury chalcogenides self‐doped nanocrystals presenting absorption features in the mid infrared range are reviewed. In particular, the results relative to the synthesis, control of doping and transport properties of HgSe colloidal nanocrystals are discussed.
Polarization‐Engineered n+GaN/InGaN/AlGaN/GaN Normally‐Off MOS HEMTs
Authors: Gregušová Dagmar , Blaho Michal , Haščík Štefan , Šichman Peter , Laurenčíková Agáta , Seifertová Alena , Dérer Ján , Brunner Frank , Würfl Joachim , Kuzmík Ján
Published: September 2017

The proposal, processing and performance of n+GaN/InGaN/AlGaN/GaN normally‐off metal‐oxide‐semiconductor (MOS) HEMTs with a recessed 2‐μm long gate/8‐μm source‐drain distance are presented. It is shown that by using a negative polarization charge at the InGaN/AlGaN interface together with 10‐nm thick Al2O3 gate insulation, a threshold voltage VT increases by 3.6 V reaching a value of ∼1.6 V. Moreover, the combination of the gate recessing through the n+GaN cap and gate insulation lead to an invariant maximal drain current of about 0.25 A mm−1, as well as decreased gate leakage current in the order of ∼10−9 A mm−1. Analytical equations explain the predictive setting of VT up to 7 V with the oxide thickness tox increase, if holes compensate the negative polarization charge. By applying tox = 30 nm a VT ∼ 3 V was obtained; p‐doping of the cap/barrier layers is suggested to reach the theoretically predicted scalability.
A DNA Origami Mechanical Device for the Regulation of Microcosmic Structural Rigidity
Authors: Wan Neng , Hong Zhouping , Wang Huading , Fu Xin , Zhang Ziyue , Li Chao , Xia Han , Fang Yan , Li Maoteng , Zhan Yi , Yang Xiangliang
Published: September 2017

DNA origami makes it feasible to fabricate a tremendous number of DNA nanostructures with various geometries, dimensions, and functionalities. Moreover, an increasing amount of research on DNA nanostructures is focused on biological and biomedical applications. Here, the reversible regulation of microcosmic structural rigidity is accomplished using a DNA origami device in vitro. The designed DNA origami monomer is composed of an internal central axis and an external sliding tube. Due to the external tube sliding, the device transforms between flexible and rigid states. By transporting the device into the liposome, the conformational change of the origami device induces a structural change in the liposome. The results obtained demonstrate that the programmed DNA origami device can be applied to regulate the microcosmic structural rigidity of liposomes. Because microcosmic structural rigidity is important to cell proliferation and function, the results obtained potentially provide a foundation for the regulation of cell microcosmic structural rigidity using DNA nanostructures.
Optical and Optoelectronic Property Analysis of Nanomaterials inside Transmission Electron Microscope
Authors: Fernando Joseph F. S. , Zhang Chao , Firestein Konstantin L. , Golberg Dmitri
Published: September 2017

In situ transmission electron microscopy (TEM) allows one to investigate nanostructures at high spatial resolution in response to external stimuli, such as heat, electrical current, mechanical force and light. This review exclusively focuses on the optical, optoelectronic and photocatalytic studies inside TEM. With the development of TEMs and specialized TEM holders that include in situ illumination and light collection optics, it is possible to perform optical spectroscopies and diverse optoelectronic experiments inside TEM with simultaneous high resolution imaging of nanostructures. Optical TEM holders combining the capability of a scanning tunneling microscopy probe have enabled nanomaterial bending/stretching and electrical measurements in tandem with illumination. Hence, deep insights into the optoelectronic property versus true structure and its dynamics could be established at the nanometer‐range precision thus evaluating the suitability of a nanostructure for advanced light driven technologies. This report highlights systems for in situ illumination of TEM samples and recent research work based on the relevant methods, including nanomaterial cathodoluminescence, photoluminescence, photocatalysis, photodeposition, photoconductivity and piezophototronics.
Recent Advances and Perspectives in Microfluidics‐Based Single‐Cell Biosensing Techniques
Authors: He Jiacheng , Brimmo Ayoola T. , Qasaimeh Mohammad A. , Chen Pengyu , Chen Weiqiang
Published: September 2017

Single‐cell analyses of secretory proteins are essential to fully understand cellular functional heterogeneity and unravel the underlying mechanisms of intercellular signaling and interactions. Retrieving dynamic information of protein secretion at single‐cell resolution reflects the precise, real‐time functional states of individual cells in physiological processes. Such measurements remain very challenging in single‐cell analysis, which requires highly integrated systems capable of performing on‐chip single‐cell isolation and subsequent real‐time protein detection. Here, recent advances in microfluidics‐based single‐cell manipulation and emerging approaches for label‐free single‐cell biosensing are reviewed. The advantages and limitations of these technologies are summarized and challenges to establish the integrated microfluidic biosensing systems for real‐time single‐cell secretomics are discussed. Recent efforts on integrated platforms for on‐chip single‐cell protein assays are highlighted and some perspectives on future directions in this field are provided.
The Microstructure Evolution of Lean Duplex Stainless Steel 2101
Authors: Feng Zhi‐Hui , Li Jing‐Yuan , Wang Yi‐De
Published: September 2017

The microstructure evolutions of lean duplex stainless steel 2101 (LDX2101) and duplex stainless steel 2205 (DSS2205) during hot deformation at 1000–1200 °C and a strain rate of 10 s−1 are investigated. The experimental results show that the difference in the two‐phase hardness of LDX2101 is greater than that in the case of DSS2205. In LDX2101, excess strain is therefore concentrated in the ferrite phase and strain transfer to the adjacent austenite phase is difficult. This also leads to greater stress concentration along the phase boundary in LDX2101, leading to edge cracking. The excess strain partitioning in ferrite leads to ferrite restoration occurring far in advance of austenite deformation, and the recrystallization of austenite is delayed accordingly. This further increases the microhardness difference between ferrite and austenite. The effects of Ni and Mn on the hot‐deformation behavior are investigated.
How Do You Listen to Your Students to Help Them Learn about Race and Racism?
Authors: Kernahan Cyndi , Chick Nancy L.
Published: September 2017

Teaching and learning can be especially difficult when the content includes race. We argue here that an effective approach is one that includes multiple angles, learning from our students and from a broad range of colleagues and disciplines.
How Do You Effectively Teach Empathy to Students?
Authors: Cuzzo Maria Stalzer Wyant , Larson Mimi Rappley , Mattsson Lisa Miller , McGlasson Terry D.
Published: September 2017

This chapter explores a multidisciplinary approach to teaching empathy in undergraduate and graduate universities. Specific recommended best practices are provided for using postmodernist methods of active teaching and learning on empathy.
How Do You Take Learning Beyond the Classroom in an Interdisciplinary First‐Year Seminar?
Authors: James Peggy , Hudspeth Christopher
Published: September 2017

We suggest four changes to the first‐year experience (FYE): reconceptualize practices of engagement as verbs rather than nouns; remove the discrete borders between teacher and student; develop manifold opportunities within FYE; and create a learning place rather than a learning space.
How Do You Achieve Inclusive Excellence in the Classroom?
Authors: Considine Jennifer R. , Mihalick Jennifer E. , Mogi‐Hein Yoko R. , Penick‐Parks Marguerite W. , Van Auken Paul M.
Published: September 2017

This chapter identifies pedagogical strategies promoting equity for all students. Historical roots of Inclusive Excellence (IE), theories surrounding IE, and ways to affirm student identity are described, as well as factors that may interfere with the adoption of inclusive pedagogy.
Seroprevalence of West Nile virus in horses in different Moroccan regions
Authors: Benjelloun Abdennasser , El Harrak Mehdi , Calistri Paolo , Loutfi Chafiqa , Kabbaj Hafsa , Conte Annamaria , Ippoliti Carla , Danzetta Maria Luisa , Belkadi Bouchra
Published: September 2017

West Nile virus‐associated disease is one of the most widespread vector‐borne diseases in the world. In Morocco, the first cases were reported in horses in 1996 and the disease re‐emerged in 2003 and in 2010. The objective of this work was to study the epidemiological situation of WNV‐associated infection in Morocco, by quantifying the seroprevalence of anti‐WNV IgM and IgG antibodies in horses in different bioclimatic regions‐zones of Morocco in 2011. During the months of May, June and July 2011, 840 serum samples were collected from horses in four regions characterized by different environmental and climatic features such as altitude, temperature and precipitation. These environmental‐climatic regions are: the Atlantic plateaus of the Gharb and pre‐Rif region, the North Atlasic plains and plateaus region, the Atlas Mountains and pre‐Atlas region and the plains and plateaus of the Oriental region. All samples were tested for the anti‐WNV IgG antibodies by ELISA and positive sera were confirmed by virus neutralization (VN). An anti‐WNV antibody prevalence map was developed. A total of 261 samples (31%) were found positive by both techniques. The prevalence of the infection was higher in the Atlantic plateaus of the Gharb and pre‐Rif region, in the northern part of the country. Available data concerning the previous WNV‐associated disease outbreaks in Morocco and the preliminary results of this serological survey suggest that the Moroccan northwest is the region at highest risk for WNV circulation. In this region, the climate is more humid with higher rainfall than other regions and milder winter temperatures exist. In the same area, the presence of migratory bird settlements may affect the risk of virus introduction and amplification.
NO(HSO4), a Fairly Ionic Solid
Authors: Beck Daniel , Belz Anja , In‐Iam Areenan , Mayer Peter , Klüfers Peter
Published: September 2017

The colourless solid NO(HSO4), known as “lead‐chamber crystals”, was investigated ever since its first preparation more than two centuries ago. Its overall ionic nature now is confirmed by X‐ray crystallography [Pna21, a = 7.3558(4), b = 6.8924(3), c = 7.7017(3) Å, Z = 4]. The next neighbours of the NO+ cations are four hydrogensulfate oxygen atoms, forming a distorted square at a distance of about 2.5 Å from the nitrogen atom. The square pattern next to the nitrogen atom is the most widespread coordination figure about an NO+ ion in a nitrosyl salt. Depending on the anion, the interaction goes along with a decrease of the N–O stretch's excitation energy.
The Decline and Rise of Institutions
Authors: Palagashvili Liya , Piano Ennio , Skarbek David
Published: September 2017

Institutions are the formal or informal 'rules of the game' that facilitate economic, social, and political interactions. These include such things as legal rules, property rights, constitutions, political structures, and norms and customs. The main theoretical insights from Austrian economics regarding private property rights and prices, entrepreneurship, and spontaneous order mechanisms play a key role in advancing institutional economics. The Austrian economics framework provides an understanding for which institutions matter for growth, how they matter, and how they emerge and can change over time. Specifically, Austrians have contributed significantly to the areas of institutional stickiness and informal institutions, self-governance and self-enforcing contracts, institutional entrepreneurship, and the political infrastructure for development.
Bureaucratizing Islam
Authors: Wainscott Ann Marie
Published: September 2017

How have states in the Middle East and North Africa responded to the War on Terror? While much scholarship has focused on terrorism in the region, there is need for critical studies of Middle Eastern states' counter-terrorism policies. This book addresses that need by investigating Morocco's unique approach to counter-terrorism: the bureaucratization of religion. Morocco's strategy is unique in the degree to which it relies on reforms that seek to make the country's religious institutions into tools for rewarding loyalty and discouraging dissent from religious elites. Through these measures they have limited opposition through an enduring form of institutional control, accommodating some of the country's most virulent critics. This book will be of great use to researchers and scholars of Middle Eastern politics, and it will also appeal to those policymakers interested in security studies and counter-terrorism policies.