bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient independent planar dose calculation for FFF IMRT QA with a bivariate Gaussian source model
Authors: Li Feifei , Park Ji‐Yeon , Barraclough Brendan , Lu Bo , Li Jonathan , Liu Chihray , Yan Guanghua 
Published: March 2017

AbstractThe aim of this study is to perform a direct comparison of the source model for photon beams with and without flattening filter (FF) and to develop an efficient independent algorithm for planar dose calculation for FF‐free (FFF) intensity‐modulated radiotherapy (IMRT) quality assurance (QA). The source model consisted of a point source modeling the primary photons and extrafocal bivariate Gaussian functions modeling the head scatter, monitor chamber backscatter, and collimator exchange effect. The model parameters were obtained by minimizing the difference between the calculated and measured in‐air output factors (Sc). The fluence of IMRT beams was calculated from the source model using a backprojection and integration method. The off‐axis ratio in FFF beams were modeled with a fourth degree polynomial. An analytical kernel consisting of the sum of three Gaussian functions was used to describe the dose deposition process. A convolution‐based method was used to account for the ionization chamber volume averaging effect when commissioning the algorithm. The algorithm was validated by comparing the calculated planar dose distributions of FFF head‐and‐neck IMRT plans with measurements performed with a 2D diode array. Good agreement between the measured and calculated Sc was achieved for both FF beams (<0.25%) and FFF beams (<0.10%). The relative contribution of the head‐scattered photons reduced by 34.7% for 6 MV and 49.3% for 10 MV due to the removal of the FF. Superior agreement between the calculated and measured dose distribution was also achieved for FFF IMRT. In the gamma comparison with a 2%/2 mm criterion, the average passing rate was 96.2 ± 1.9% for 6 MV FFF and 95.5 ± 2.6% for 10 MV FFF. The efficient independent planar dose calculation algorithm is easy to implement and can be valuable in FFF IMRT QA.
A test of a skeletal ageing method based on resorption of the alveolar crest following tooth loss using a skeletal population of documented age at death
Authors: Mays Simon 
Published: March 2017

AbstractObjectivesResorption of the alveolar process occurs following tooth loss, and appears to continue for a prolonged period. Previous study (Mays, ) with a known‐age collection of human remains suggested the potential of this phenomenon for age estimation in remains of adults who have lost one or more molar teeth. This article tests this ageing technique on another known age group, and attempts to evaluate the impact of some extraneous factors on the method.Materials and methodsThe study group comprises adult skeletons (N = 110) of documented age at death from 18th to 19th century London. It examines the relationship between a previously described standardized measure of posterior corpus height (SPCH) in mandibles showing loss of one or more molars. The potential influence of a general tendency to form or lose bone (identified by the presence of ossification into the anterior longitudinal ligament of the spine and cortical thickness at the metacarpal) and (for females) parity are also investigated.ResultsNegative age correlation was found for SPCH in females but not in males. In females, the age‐association was weaker, and the rate of loss slower, than in a previously studied 19th century European population. None of the other factors investigated showed a relationship with SPCH.DiscussionAs with other bony age indicators, the relationship between SPCH and age varies in different populations. Further work is needed to evaluate the extraneous factors that affect the relationship with age.
Stabilization of High Oxidation State Upconversion Nanoparticles by N‐Heterocyclic Carbenes
Authors: Möller Nadja , Rühling Andreas , Lamping Sebastian , Hellwig Tim , Fallnich Carsten , Ravoo Bart Jan , Glorius Frank 
Published: March 2017

AbstractThe stabilization of high oxidation state nanoparticles by N‐heterocyclic carbenes is reported. Such nanoparticles represent an important subset in the field of nanoparticles, with different and more challenging requirements for suitable ligands compared to elemental metal nanoparticles. N‐Heterocyclic carbene coated NaYF4:Yb,Tm upconversion nanoparticles were synthesized by a ligand‐exchange reaction from a well‐defined precursor. This new photoactive material was characterized in detail and employed in the activation of photoresponsive molecules by low‐intensity near‐infrared light (λ=980 nm).
Toughening of polyamide‐6 with little loss in modulus by block copolymer containing poly(styrene‐alt‐maleic acid) segment
Authors: He Ren , Zhan Xiaoli , Zhang Qinghua , Chen Fengqiu 
Published: March 2017

ABSTRACTToughening of polyamide‐6 (PA6) by elastomers without sacrificing the modulus of blends has always been a challenge. In this study, PA6 was modified by poly(styrene‐alt‐maleic acid)‐block‐polystyrene‐block‐poly(n‐butyl acrylate)‐block‐polystyrene tetrablock copolymer (BCP) elastomer. The introduced acid groups in BCP resulted in the size of BCP inclusions down to nanometers in polyamide matrix. 10 wt % of BCP‐modified PA6 blends achieved five times increase in notched impact strength with almost no loss in modulus. Microscopic observations suggested the cavitation of elastomer particles and shear yielding of PA6 matrix to be the major toughening mechanism. This research provides a strategy to toughen polyamides by block copolymers at very low rubber content. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44849.
Core–shell hexadecane‐polyurethane nanofiber/net structured membrane: Evaluation of surfactant addition on morphology and performance
Authors: Rahimi Massoumeh , Mokhtari Javad 
Published: March 2017

ABSTRACTCoelectrospinning/netting or fabrication of well‐controlled nanofibers/net (NFN) within core–shell hexadecane (HD)–polyurethane (PU) nanofiber membranes is an effective strategy to improve nanostructure morphology, mechanical properties, and performance characteristics. Three types of surfactants were separately added to PU solutions in order to make controlled NFN layers within membrane structures. The experimental results indicated that the NFN layers composed of core–shell nanowires with a diameter of 20–40 nm increased significantly when a cationic surfactant was added. Also, the results confirmed that the NFN structure caused a significant increase in strength and a noticeable decrease in elongation of the membranes. The performance characteristics of the membranes, such as water vapor transmission rate and hydrostatic pressure, were not affected significantly by the addition of the cationic surfactant. The results confirmed that the mechanical properties and morphology of the core–shell HD‐PU nanofiber membranes could be controlled and tuned by the amount and type of surfactant. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45047.
Contrasting influences of inundation and land use on the rate of floodplain restoration
Authors: Dawson Samantha K. , Kingsford Richard T. , Berney Peter , Catford Jane A. , Keith David A. , Stoklosa Jakub , Hemmings Frank A. 
Published: March 2017

Abstract

This study examined the assisted natural restoration of native vegetation in an Australian floodplain wetland where flows were reinstated and the river was reconnected to the floodplain, following cessation of agricultural cultivation.
Extant vegetation was surveyed three times during an inundation event at plots with different land‐use histories.
Restoration rate was more influenced by past land use than long‐term inundation frequency and success decreased with antecedent land‐use intensity. Prolonged land‐use history (>3 years cultivation) restricted restoration success. Sites with longer cultivation histories tended to have fewer aquatic species, more terrestrial species and exotic species. For example, amphibious responders with floating leaves were found only in reference plots and less frequently in farmed treatment plots. In this scenario, increased persistence of exotics and dryland species suggested alternative trajectories. Fields with a short land‐use history (1–3 years of clearing and cultivation) resembled undisturbed floodplain communities, consistent with a ‘field of dreams’ hypothesis.
Although river–floodplain reconnections can restore wetlands, legacy effects of past land use may limit the pace and outcomes of restoration.
Recommendations for monitoring freshwater fishes in river restoration plans: A wasted opportunity for assessing impact
Authors: Rodeles Amaia A. , Galicia David , Miranda Rafael 
Published: March 2017

Abstract

Many human activities in and on rivers cause the loss of freshwater biodiversity, especially fish, which now are one of the most endangered vertebrate groups. River fragmentation caused by the construction of dams is one of the main threats to fish species. In Spain, which has the highest number of dams per square kilometre in the world, more than half of all fish species are threatened by these constructions. The government has initiated the National Strategy for River Restoration, a plan to restore rivers and preserve their inhabitants, which includes the removal of dams.
An information search and query was conducted to determine if fish monitoring was performed before and after dam removal, and the result was negative. Therefore, an assessment of the effects of dam removal on fish communities at a large spatial scale was not possible. Instead, an analysis was carried out to measure the effects of dam removal on river connectivity using a geometric network.
The analysis of river connectivity improvement showed that 66% of removed dams had one or more dams less than 5 km away. The removal of dams increased the connected river length by an average of 6.4 km per dam removed, with the range varying between 1.04 km and 9.48 km, depending on the river basin.
These results show that, although monitoring programmes are strongly recommended after restoration actions, they are not usually performed. This is a wasted opportunity to gather large datasets to understand better the effects of human actions on fish communities and on rivers.
River connectivity results may reflect a demolition strategy based more on economic and social opportunism rather than on ecological considerations. It is strongly recommended that dam removal plans should be based on ecological selection methods to achieve greater river improvements with less investment.
On a correlation among azimuthal velocities and the flyby anomaly sign
Authors: Acedo L. , Bel Ll. 
Published: March 2017

BackgroundData of six flybys, those of Galileo I, Galileo II, NEAR, Cassini, Rosetta, and Messenger were reported by Anderson et al. (2008). Four of them: Galileo I, NEAR, Rosetta, and Messenger gain Newtonian energy during the flyby transfer, while Galileo II and Cassini lose energy. In both cases this is a surprising anomaly since Newtonian forces originate from a potential and they are, therefore, conservative.Materials and MethodsWe use a Whiteheadian theory of gravity to analyze the anomalies.ResultsHere we show that the gravitational field of a rotating planet, as derived from this new model, introduces a nonconservative force that gives a partial, but in our opinion satisfactory, explanation of these anomalies.ConclusionThis model also suggests a correlation between the sign of the anomaly and the sign of the azimuthal velocity at perigee.
Maßgeschneiderte Bauwerke mit BIM
Authors: Braun Matthias , Laufkötter Alrun , Hochmuth Markus 
Published: March 2017

AbstractIn den Zeiten vor der objektorientierten Planung musste der Ingenieur das zunächst nur in seiner eigenen dreidimensionalen Vorstellung existierende Bauwerk auf eine zweidimensionale Darstellung im Plan herunterbrechen. Dank BIM muss er diese Abstraktion heute nicht mehr durchführen. Er plant jetzt dreidimensional inklusive aller zugehörigen Mengen und Kosten, die als zusätzliche Informationen im Modell enthalten sind. Der Bauherr erhält mit der Planung eine optimierte Entscheidungsgrundlage und kann seine eigenen Schwerpunkte setzen. Somit ist der Planer in der Lage, das Bauwerk optimal an eine Vielzahl an Vorgaben anzupassen. Was hier möglich ist, zeigen ausgewählte Projektbeispiele aus dem Hoch‐ und Ingenieurbau.
A highly selective colorimetric and fluorescent dual‐modal probe for the rapid determination of fluoride anions
Authors: Li Changsuo , Tang Chengcheng , Xing Liting , Sun Bin , Cheng Shiyu , Liao Qiang , Zhu Baocun 
Published: March 2017

AbstractIn this work, 4‐(p‐hydroxybenzylidenehydrazino)‐N‐butyl‐1,8‐naphthalimide (1) has been designed and synthesized as a colorimetric and fluorescent dual‐modal probe for F−. Compound 1 immediately detected inorganic fluoride salts using UV/vis absorption and fluorescence spectroscopy methods, and served as a ‘naked‐eye’ indicator for F− with high selectivity and sensitivity. Both the absorption and fluorescence spectra show excellent linearity with the concentration of F−. Real‐life applications demonstrated that our proposed analytical system provided a satisfactory method for the determination of F−. In addition, the reaction mechanism of deprotonation was confirmed by 1H NMR.
High throughput inclusion body sizing: Nano particle tracking analysis
Authors: Reichelt Wieland N. , Kaineder Andreas , Brillmann Markus , Neutsch Lukas , Taschauer Alexander , Lohninger Hans , Herwig Christoph 
Published: March 2017

AbstractThe expression of pharmaceutical relevant proteins in Escherichia coli frequently triggers inclusion body (IB) formation caused by protein aggregation. In the scientific literature, substantial effort has been devoted to the quantification of IB size. However, particle‐based methods used up to this point to analyze the physical properties of representative numbers of IBs lack sensitivity and/or orthogonal verification. Using high pressure freezing and automated freeze substitution for transmission electron microscopy (TEM) the cytosolic inclusion body structure was preserved within the cells. TEM imaging in combination with manual grey scale image segmentation allowed the quantification of relative areas covered by the inclusion body within the cytosol. As a high throughput method nano particle tracking analysis (NTA) enables one to derive the diameter of inclusion bodies in cell homogenate based on a measurement of the Brownian motion. The NTA analysis of fixated (glutaraldehyde) and non‐fixated IBs suggests that high pressure homogenization annihilates the native physiological shape of IBs. Nevertheless, the ratio of particle counts of non‐fixated and fixated samples could potentially serve as factor for particle stickiness. In this contribution, we establish image segmentation of TEM pictures as an orthogonal method to size biologic particles in the cytosol of cells. More importantly, NTA has been established as a particle‐based, fast and high throughput method (1000–3000 particles), thus constituting a much more accurate and representative analysis than currently available methods.
Targeted sequencing identifies genetic polymorphisms of flavin‐containing monooxygenase genes contributing to susceptibility of nicotine dependence in European American and African American
Authors: Zhang Tian‐Xiao , Saccone Nancy L. , Bierut Laura J. , Rice John P. 
Published: March 2017

AbstractBackgroundSmoking is a leading cause of preventable death. Early studies based on samples of twins have linked the lifetime smoking practices to genetic predisposition. The flavin‐containing monooxygenase (FMO) protein family consists of a group of enzymes that metabolize drugs and xenobiotics. Both FMO1 and FMO3 were potentially susceptible genes for nicotine metabolism process.MethodsIn this study, we investigated the potential of FMO genes to confer risk of nicotine dependence via deep targeted sequencing in 2,820 study subjects comprising 1,583 nicotine dependents and 1,237 controls from European American and African American. Specifically, we focused on the two genomic segments including FMO1, FMO3, and pseudo gene FMO6P, and aimed to investigate the potential association between FMO genes and nicotine dependence. Both common and low‐frequency/rare variants were analyzed using different algorithms. The potential functional significance of SNPs with association signal was investigated with relevant bioinformatics tools.ResultsWe identified different clusters of significant common variants in European (with most significant SNP rs6674596, p = .0004, OR = 0.67, MAF_EA = 0.14, FMO1) and African Americans (with the most significant SNP rs6608453, p = .001, OR = 0.64, MAF_AA = 0.1, FMO6P). No significant signals were identified through haplotype‐based analyses. Gene network investigation indicated that both FMO1 and FMO3 have a strong relation with a variety of genes belonging to CYP gene families (with combined score greater than 0.9). Most of the significant variants identified were SNPs located within intron regions or with unknown functional significance, indicating a need for future work to understand the underlying functional significance of these signals.ConclusionsOur findings indicated significant association between FMO genes and nicotine dependence. Replications of our findings in other ethnic groups were needed in the future. Most of the significant variants identified were SNPs located within intronic regions or with unknown functional significance, indicating a need for future work to understand the underlying functional significance of these signals.
Bifunctional Tripeptide with a Phosphonic Acid as a Brønsted Acid for Michael Addition: Mechanistic Insights
Authors: Cortes‐Clerget Margery , Jover Jesús , Dussart Jade , Kolodziej Emilie , Monteil Maelle , Migianu‐Griffoni Evelyne , Gager Olivier , Deschamp Julia , Lecouvey Marc 
Published: March 2017

AbstractEnamine catalysis is a widespread activation mode in the field of organocatalysis and is often encountered in bifunctional organocatalysts. We previously described H‐Pro‐Pro‐pAla‐OMe as a bifunctional catalyst for Michael addition between aldehydes and aromatic nitroalkenes. Considering that opposite selectivities were observed when compared to H‐Pro‐Pro‐Glu‐NH2, an analogue described by Wennemers, the activation mode of H‐Pro‐Pro‐pAla‐OMe was investigated through kinetic, linear effect studies, NMR analyses, and structural modifications. It appeared that only one bifunctional catalyst was involved in the catalytic cycle, by activating aldehyde through an (E)‐enamine and nitroalkene through an acidic interaction. A restrained tripeptide structure was optimal in terms of distance and rigidity for better selectivities and fast reaction rates. Transition‐state modeling unveiled the particular selectivity of this phosphonopeptide.
Fluorinated Unsymmetrical N,N′‐Diaryl Imidazolium Salts—New Functionalized NHC‐Ligand Precursors
Authors: Topchiy Maxim A. , Zotova Maria A. , Masoud Salekh M. , Mailyan Artur K. , Ananyev Ivan V. , Nefedov Sergey E. , Asachenko Andrey F. , Osipov Sergey N. 
Published: March 2017

AbstractAn efficient and scaled‐up synthesis of the imidazol‐2‐ylidene‐based unsymmetrical NHC precursors bearing the sterically demanding hexafluoroisopropylalkoxy group [(CF3)2(OR)C−] at the ortho position of the N‐aryl substituent was developed. The key step of the method involved the transformation of a Mes‐substituted oxazolinium tetrafluoroborate salt through the reaction with the corresponding binucleophilic fluoroalkyl‐substituted aniline. The subsequent post‐modification of the resulting hydroxyl‐containing salt through a simple one‐step O‐alkylation protocol provided access to a new family of unsymmetrical fluorinated NHC precursors. These compounds were successfully utilized for the preparation of several novel metal complexes. The molecular structures of some NHC precursors and their metal complexes have been unambiguously characterized by single‐crystal X‐ray diffraction analysis. A preliminary evaluation of the catalytic activity of the palladium complexes was performed on a Buchwald–Hartwig amination reaction. As a result, two PEPPSI‐type (PEPPSI=pyridine‐enhanced pre‐catalyst preparation stabilization and initiation) Pd complexes have demonstrated promising activity in alkane solvents.
Efficient Benzodithiophene/Benzothiadiazole‐Based n‐Channel Charge Transporters
Authors: Sandoval‐Torrientes Rafael , Calbo Joaquín , Matsuda Wakana , Choi Wookjin , Santos José , Seki Shu , Ortí Enrique , Martín Nazario 
Published: March 2017

AbstractA series of donor–acceptor (D‐A) small molecules based on electron‐deficient benzothiadiazole (BTD) and electron‐rich benzodithiophene (BDT) featuring an A‐D‐A structure is presented. Exhaustive spectroscopic, electrochemical, and computational studies evidence their electroactive nature and their ability to form well‐ordered thin films with broad visible absorptions and low band gaps (ca. 2 eV). Time‐resolved microwave conductivity (TRMC) studies unveil unexpected n‐type charge transport displaying high electron mobilities around 0.1 cm2 V−1 s−1. Efficient electron transport properties are consistent with the low electron reorganization energies (0.11–0.17 eV) theoretically predicted.
Long‐term and widespread changes in agricultural practices influence ring‐necked pheasant abundance in California
Authors: Coates Peter S. , Brussee Brianne E. , Howe Kristy B. , Fleskes Joseph P. , Dwight Ian A. , Connelly Daniel P. , Meshriy Matt G. , Gardner Scott C. 
Published: March 2017

AbstractDeclines in bird populations in agricultural regions of North America and Europe have been attributed to agricultural industrialization, increases in use of agrochemical application, and increased predation related to habitat modification. Based on count data compiled from Breeding Bird Survey (BBS) from 1974 to 2012, Christmas Bird Count (CBC) collected from 1914 to 2013, and hunter data from Annual Game Take Survey (AGTS) for years 1948–2010, ring‐necked pheasants (Phasianus colchicus) in California have experienced substantial declines in agricultural environments. Using a modeling approach that integrates all three forms of survey data into a joint response abundance index, we found pheasant abundance was related to the amount of harvested and unharvested crop land, types of crops produced, amount of total pesticide applied, minimum temperature, precipitation, and numbers of avian competitors and predators. Specifically, major changes in agricultural practices over the last three decades were associated with declines in pheasant numbers and likely reflected widespread loss of habitat. For example, increases in cropland were associated with increased pheasant abundance during early years of study but this effect decreased through time, such that no association in recent years was evidenced. A post hoc analysis revealed that crops beneficial to pheasant abundance (e.g., barley) have declined substantially in recent decades and were replaced by less advantageous crops (e.g., nut trees). An additional analysis using a restricted data set (1990–2013) indicated recent negative impacts on pheasant numbers associated with land use practices were also associated with relatively high levels of pesticide application. Our results may provide valuable information for management policies aimed at reducing widespread declines in pheasant populations in California and may be applicable to other avian species within agricultural settings. Furthermore, this general analytical approach is not limited to pheasants and could be applied to other taxa for which multiple survey data sources exist.