bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of military training on breeding ecology of Bachman's sparrow
Authors: Fish Alexander C. , Moorman Christopher E. , Schillaci Jessica M. , DePerno Christopher S. 
Published: October 2018

ABSTRACTAnthropogenic disturbance may cause birds to flush and relocate, abandon breeding sites, experience increased nest failure, or fledge fewer young. Ground‐based military activities are of particular concern for ground‐nesting birds because of the increased risk of nest destruction and trampling of vegetation. We investigated how different intensities of disturbance from ground‐based military training affected reproductive ecology of Bachman's sparrow (Peucaea aestivalis) from 2014–2016, on Fort Bragg Military Installation, North Carolina, USA. We designated 2 training intensity regimes and monitored sparrows at 6 observation areas, 3 in high‐intensity training areas (i.e., foot traffic every 1–3 days) and 3 in low‐intensity training (i.e., foot traffic <1 per month) areas. We compared seasonal productivity metrics and daily nest survival between training intensities. Additionally, we compared male sparrow relative abundance and micro‐habitat use between high‐ and low‐intensity training areas. We monitored 106 male territories and located 110 nests opportunistically and by tracking telemetered female sparrows. We used fixed‐radius point counts to estimate relative abundance in each observation area and measured vegetation composition and structure at a subset of 10 locations in each male territory. Seasonal productivity metrics, daily nest survival, relative abundance, and vegetation composition and structure at male locations did not differ between areas with high and low military training intensity. In 2015, 1 sparrow nest was trampled by military personnel, but ≥1 nestling force‐fledged and the nest was considered successful. Bachman's sparrow nesting ecology was not affected by intensity of ground‐based military training activity, likely because activity was sufficiently dispersed across the landscape, even in high‐intensity training areas. We recommend ground‐based training attempts to minimize ground vegetation destruction by dispersing large groups and traversing variable routes when in forested uplands. © 2018 The Wildlife Society.
The Trichodesmium microbiome can modulate host N2 fixation
Authors: Frischkorn Kyle R. , Rouco Mónica , Van Mooy Benjamin A. S. , Dyhrman Sonya T. 
Published: October 2018

Abstract
Trichodesmium is a marine, diazotrophic cyanobacterium that plays a central role in the biogeochemical cycling of carbon and nitrogen. Colonies ubiquitously co‐occur with a diverse microbiome of heterotrophic bacteria. We show that manipulation of the microbiome with quorum sensing acyl homoserine lactones (AHLs) significantly modulated rates of N2 fixation by Trichodesmium collected from the western North Atlantic, with positive and negative effects of varied magnitude. Changes in Trichodesmium N2 fixation did not correlate with changes in microbiome composition or geochemistry. With AHL addition, a subset of the significantly differentially expressed genes was related to known quorum sensing responses in model bacteria. However, there was little overlap in specific microbiome transcriptional responses to AHL addition between stations. Overall, these host‐microbiome interactions reflect a complex interplay of biotic and environmental factors that together form an overlooked mechanism modulating Trichodesmium N2 fixation.
Using in situ UV‐Visible spectrophotometer sensors to quantify riverine phosphorus partitioning and concentration at a high frequency
Authors: Vaughan Matthew C. H. , Bowden William B. , Shanley James B. , Vermilyea Andrew , Wemple Beverley , Schroth Andrew W. 
Published: October 2018

AbstractAccurate riverine phosphorus concentration measurements are often critical to meet watershed management goals. Phosphorus monitoring programs often rely on proxy variables such as turbidity and discharge and have limited ability to accurately estimate concentrations of dissolved phosphorus fractions that are most bioavailable. Optical water quality sensors can make subhourly measurements and have been shown to reduce uncertainty in load estimates and reveal high‐frequency storm dynamics for nitrate and dissolved organic carbon. We evaluated the utility of in situ UV‐Visible spectrophotometers to predict total, dissolved, and soluble reactive phosphorus concentrations in streams draining agricultural, urban, and forested land use/land covers. We present the first statistically validated application of optical water quality sensors to demonstrate how sensors may perform in predicting phosphorus fraction concentrations through training set models. Total phosphorus predictions from UV‐Visible spectra were optimal when models were site‐specific, and the proportion of variance explained was generally as high as or higher than the results of other studies that rely only on discharge and turbidity. However, root mean square errors for total phosphorus models were relatively high compared to the median concentrations at each site. Models to predict dissolved and soluble reactive phosphorus concentrations explained a greater proportion of the variance than any other known proxy variable technique, and results varied by land use/land cover. Though accuracy limitations remain, this approach has potential to predict concurrent total, dissolved, and soluble reactive phosphorus concentrations at a high frequency for many applications in water quality research and management communities.
Electrically Injected Parity Time–Symmetric Single Transverse–Mode Lasers
Authors: Yao Ruizhe , Lee Chi‐Sen , Podolskiy Viktor , Guo Wei 
Published: October 2018

AbstractSingle transverse–mode operation of broad area–coupled waveguide lasers enabled by parity‐time (PT) symmetry is demonstrated. The PT‐symmetric laser operates on coupled waveguide cavities with electrically tuned gain and loss. Such a counterintuitive waveguide design enables PT‐symmetric breaking, causing unique mode selection and ultimately enables single‐mode operation. By electrically tuning the loss in the loss region of the coupled waveguide cavity, several different PT‐symmetric phases are analyzed theoretically, and the corresponding PT‐symmetric phase transition is demonstrated experimentally in the coupled waveguide laser.
Tropoelastin is a Flexible Molecule that Retains its Canonical Shape
Authors: Tarakanova Anna , Yeo Giselle C. , Baldock Clair , Weiss Anthony S. , Buehler Markus J. 
Published: October 2018

AbstractTropoelastin is the dominant building block of elastic fibers, which form a major component of the extracellular matrix, providing structural support to tissues and imbuing them with elasticity and resilience. Recently, the atomistic structure of human tropoelastin is described, obtained through accelerated sampling via replica exchange molecular dynamics simulations. Here, principal component analysis is used to consider the ensemble of structures accessible to tropoelastin at body temperature (37 °C) at which tropoelastin naturally self‐assembles into aggregated coacervates. These coacervates are relevant because they are an essential intermediate assembly stage, where tropoelastin molecules are then cross‐linked at lysine residues and integrated into growing elastic fibers. It is found that the ensemble preserves the canonical tropoelastin structure with an extended molecular body flanked by two protruding legs, and identifies variations in specific domain positioning within this global shape. Furthermore, it is found that lysine residues show a large variation in their location on the tropoelastin molecule compared with other residues. It is hypothesized that this perturbation of the lysines increases their accessibility and enhances cross‐linking. Finally, the principal component modes are extracted to describe the range of tropoelastin's conformational fluctuation to validate tropoelastin's scissor‐twist motion that was predicted earlier.
Non‐Newtonian Polymer–Nanoparticle Hydrogels Enhance Cell Viability during Injection
Authors: Lopez Hernandez Hector , Grosskopf Abigail K. , Stapleton Lyndsay M. , Agmon Gillie , Appel Eric A. 
Published: October 2018

AbstractDrug delivery and cell transplantation require minimally invasive deployment strategies such as injection through clinically relevant high‐gauge needles. Supramolecular hydrogels comprising dodecyl‐modified hydroxypropylmethylcellulose and poly(ethylene glycol)‐block‐poly(lactic acid) have been previously demonstrated for the delivery of drugs and proteins. Here, it is demonstrated that the rheological properties of these hydrogels allow for facile injectability, an increase of cell viability after injection when compared to cell viabilities of cells injected in phosphate‐buffered saline, and homogeneous cell suspensions that do not settle. These hydrogels are injected at 1 mL min−1 with pressures less than 400 kPa, despite the solid‐like properties of the gel when at rest. The cell viabilities immediately after injection are greater than 86% for adult human dermal fibroblasts, human umbilical vein cells, smooth muscle cells, and human mesenchymal stem cells. Cells are shown to remain suspended and proliferate in the hydrogel at the same rate as observed in cell media. The work expands on the versatility of these hydrogels and lays a foundation for the codelivery of drugs, proteins, and cells.
Molybdenum Carbonyl Complexes with a Polymerizable Phosphorus/Nitrogen/Phosphorus Ligand and Corresponding Conducting Metallopolymers
Authors: Keskin Seyma Goren , Mejia Michelle L. , Cowley Alan H. , Holliday Bradley J. 
Published: October 2018

AbstractThe design, synthesis, and characterization of the novel polymerizable ligand 3,5‐bis(3,4‐ethylenedioxythien‐2‐yl)‐N,N‐bis(2‐diphenylphosphinoethyl)‐phenylamine is achieved. The corresponding molybdenum complexes (EDOT)2PNP‐Mo(CO)
n
where n = 3,4 with carbonyls as ancillary ligands are also synthesized, and characterized by 1H NMR, 31P{1H} NMR, HRMS, FTIR (both the solution state spectrum between KBr discs and the solid‐state spectrum with attenuated total reflectance [ATR] apparatus). Single crystal X‐ray analysis of (EDOT)2PNP‐Mo(CO)3 complex is performed. The monomer complexes and the free ligand are electropolymerized to obtain the corresponding polymers that are studied electrochemically. The Mo/P and Mo/S ratios as well as the metal oxidations in the conducting metallopolymers are analyzed by X‐ray photoelectron spectroscopy.
From Wall Slip to Bulk Shear Banding in Entangled Polymer Solutions
Authors: Wang Shi‐Qing 
Published: October 2018

AbstractThis article reviews the past activities and emergent understanding of nonlinear rheology of entangled polymeric liquids, with the purpose of pointing out the remaining challenges. A key component of this subject concerns wall slip and shear strain localization, for example, shear banding. It is emphasized that wall slip and shear banding are not isolated phenomena and share the same conceptual origin. The concept of the extrapolation length identified for quantification of the magnitude of wall slip is equally useful in determining whether shear banding would occur. An adequate estimate of the extrapolation length is essential for the description of shear banding. This paper concludes by listing some remaining challenges in the field of nonlinear polymer rheology.
Exceptionally High CO2 Adsorption at 273 K by Microporous Carbons from Phenolic Aerogels: The Role of Heteroatoms in Comparison with Carbons from Polybenzoxazine and Other Organic Aerogels
Authors: Majedi Far Hojat , Rewatkar Parwani M. , Donthula Suraj , Taghvaee Tahereh , Saeed Adnan Malik , Sotiriou‐Leventis Chariklia , Leventis Nicholas 
Published: October 2018

AbstractPhenolic aerogels containing oxygen and other polymeric aerogels containing both oxygen and nitrogen (polybenzoxazine and a polyamide‐polyimide‐polyurea co‐polymer) are converted to carbon aerogels (800 °C/Ar), and are etched with CO2 (1000 °C). Etching opens closed pores and increases micropore volumes and size. Heteroatoms are retained in the etched samples. All carbon aerogels are evaluated as CO2 absorbers in terms of their capacity and selectivity toward CH4, H2, and N2. CO2 adsorption capacity is linked to microporosity. In most cases, monolayer coverage of micropore walls is enough to explain CO2 uptake quantitatively. The interaction of CO2 with micropore walls is evaluated via isosteric heats of adsorption, and is stronger with carbons containing only oxygen heteroatoms. The adsorption capacity of those carbons (5–6 mmol g−1) is on par with the best carbon and polymeric CO2 adsorbers known in the literature, with one exception however: etched carbon aerogels from low‐density resorcinol‐formaldehyde aerogels show a very high CO2 uptake (14.8 ± 3.9 mmol g−1 at 273 K, 1 bar) attributed to a pore‐filling process that proceeds beyond monolayer coverage, whereas surface phenoxides engage in a thermally neutral carbonate forming reaction (surface‐O– + CO2 → surface‐O–(CO)–O–) that continues until micropores are filled.
Ultrasound‐Assisted Synthesis of Cross‐Linked Poly(ethylene glycol) Nanostructures with Hydrophobic Core and Hydrophilic Shell
Authors: Zhu Haiyan , Cavalieri Francesca , Ashokkumar Muthupandian 
Published: October 2018

AbstractOne‐pot synthesis of polymeric nanostructures, by using ultrasound without adding initiators and surfactants, is a straightforward approach that has attracted significant attention in polymer science. In this study, the ultrasonic polymerization technique is employed to synthesize poly(ethylene glycol) based nanoparticles with a hydrophobic core and a hydrophilic shell. Interfacial polymerization is performed using an oil‐in‐water emulsion containing oligo (ethylene glycol) methyl ether methacrylate as a water‐soluble monomer, and ethylene glycol dimethacrylate acting as an oily‐cross‐linker phase. Both the radicals and physical effects generated by acoustic cavitation are crucial to conduct this surfactant and initiator‐free process and obtain uniform nanoparticles endowed with a hydrophobic core and hydrophilic shell. It is shown that the nanoparticle's core can be loaded with hydrophobic compounds. This technique can be applied to different monomers containing various functional moieties such as amines and carboxyl groups to obtain multifunctional nanoparticles.
Connectedness of the continuum in intuitionistic mathematics
Authors: Bickford Mark 
Published: October 2018

AbstractWorking in (Intuitionistic analysis) we prove a strong, constructive connectedness property of the continuum: for any non‐empty sets, A and B, if then is non‐empty. It is well known that the intuitionistic continuum is indecomposable: if and then or , but this property is essentially negative—equivalent to if A, B are non‐empty and then . Our connectedness property is positive; so, given , , and a witness to , to prove our theorem we must construct a real number . We can construct the needed real number using only Bishop's constructive mathematics () and a weak form of Brouwer's continuity principle (and the choice principles that come from the Brouwer‐Heyting‐Kolmogorov interpretation of quantifiers in constructive type theory). We also replace indecomposability by connectedness in some results of van Dalen that use additional intuitionistic axioms.
Multicompartment Polymeric Nanoreactors for Non‐Orthogonal Cascade Catalysis
Authors: Womble C. Tyler , Kuepfert Michael , Weck Marcus 
Published: October 2018

AbstractSpatial confinement of multiple catalysts presents an effective strategy for performing sequential or tandem chemical transformations in a one‐pot reaction. These methods may be used to catalyze numerous reactions in conditions that are otherwise incompatible between catalyst and solvent, different catalysts, or reagents. Appropriate site isolation or support structure design will lead to significant advantages in atom economy, purification, and costs; the development of the interface between a catalyst and its confined microenvironment is paramount for realizing the next generation of nanoreactors. Polymer scaffolds can create tailor‐made microenvironments resulting in catalyst compartmentalization. Through the optimization of a number of variables such as size, solubility, functionality, and morphology of the nanoreactor, catalyst activity and selectivity can be tuned. In this feature article, design principles and early strategies for polymer supports for catalyst site‐isolation are introduced, and current strategies toward multicompartment polymer nanoreactors for non‐orthogonal cascade catalysis are discussed. Future design trends in this burgeoning field are outlined in the conclusion.
Synthesis of Multifunctional Homopolymers through Using Thiazolidine Chemistry and Post‐Polymerization Modification
Authors: Kubo Tomohiro , Swartz Jeremy L. , Scheutz Georg M. , Sumerlin Brent S. 
Published: October 2018

AbstractMultifunctional homopolymers, defined here as polymers that contain multiple reactive functional groups per repeat unit, are versatile scaffolds for preparing complex macromolecules via post‐polymerization modification. However, there are limited methods for preparing multifunctional homopolymers that contain more than one nucleophilic site per repeat unit. Herein, a strategy to synthesize a multifunctional homopolymer using thiazolidine chemistry is demonstrated. Controlled radical polymerization of a thiazolidine‐containing acrylamido monomer allows for the synthesis of a polymer with pendent latent nucleophiles. Ring‐opening of the thiazolidine affords a homopolymer with two side‐chain reactive sites, an amine and a thiol. One‐pot functionalization via disulfide formation and acyl substitution is performed to introduce two distinct groups in each repeat unit.
Design of Potent Panobinostat Histone Deacetylase Inhibitor Derivatives: Molecular Considerations for Enhanced Isozyme Selectivity between HDAC2 and HDAC8
Authors: Stoddard Shana V. , May Xavier A. , Rivas Fatima , Dodson Kyra , Vijayan Sajith , Adhika Swetha , Parker Kordarius , Watkins Davita L. 
Published: October 2018

AbstractHistone Deacetylases (HDACs) are an important family of 18 isozymes, which are being pursued as drug targets for many types of disorders. HDAC2 and HDAC8 are two of the isozymes, which have been identified as drug targets for the design of anti‐cancer, neurodegenerative, immunological, and anti‐parasitic agents. Design of potent HDAC2 and HDAC8 inhibitors will be useful for the therapeutic advances in many disorders. This work was undertaken to develop potent HDAC2 and HDAC8 inhibitors. A docking study was performed comparing panobinostat derivatives in both HDAC2 and HDAC8. Six of our derivatives showed stronger binding to HDAC2 than panobinostat, and two of our derivatives showed stronger binding to HDAC8 than panobinostat. We evaluated the molecular features, which improved potency of our inhibitors over panobinostat and also identified another molecular consideration, which could be used to enhance histone deacetylase inhibitor (HDACi) selectivity towards either the HDAC2 or HDAC8 isozymes. The results of this work can be used to assist future design of more potent and selective HDACi for HDAC2 and HDAC8.
Broadband dual‐polarized MICROSTRIP antenna fed with horizontal coaxial baluns
Authors: Row Jeen‐Sheen , Ko Ting‐Hung 
Published: October 2018

AbstractA novel feed mechanism for dual‐polarized microstrip patch antennas with broadband operation and high isolation is presented. The feed structure is a coaxial balun composed of coaxial cables and copper tubes, and it is placed parallel to the ground plane. With the horizontal coaxial baluns, the radiating patch can be symmetrically excited through proximity coupling. For the proposed feed mechanism, the parametric analyses are performed, and the critical dimension affecting the impedance bandwidth of the microstrip antenna is also addressed. An antenna prototype is constructed, and its measured results indicate that the microstrip antenna can give an impedance bandwidth of more than 20%, and within the bandwidth, the isolation between the two orthogonal ports is higher than 40 dB; moreover, symmetrical broadside radiation with low cross polarization is obtained. Simulated results for the cases of microstrip antennas with various substrate thicknesses are also provided.
Quantitative 3D dynamic contrast‐enhanced (DCE) MR imaging of carotid vessel wall by fast T1 mapping using Multitasking
Authors: Wang Nan , Christodoulou Anthony G. , Xie Yibin , Wang Zhenjia , Deng Zixin , Zhou Bill , Lee Sangeun , Fan Zhaoyang , Chang Hyukjae , Yu Wei , Li Debiao 
Published: October 2018

PurposeTo develop a dynamic contrast‐enhanced (DCE) MRI method capable of high spatiotemporal resolution, 3D carotid coverage, and T1‐based quantification of contrast agent concentration for the assessment of carotid atherosclerosis using a newly developed Multitasking technique.Methods5D imaging with 3 spatial dimensions, 1 T1 recovery dimension, and 1 DCE time dimension was performed using MR Multitasking based on low‐rank tensor modeling, which allows direct T1 quantification with high spatiotemporal resolution (0.7 mm isotropic and 595 ms, respectively). Saturation recovery preparations followed by 3D segmented fast low angle shot readouts were implemented with Gaussian‐density random 3D Cartesian sampling. A bulk motion removal scheme was developed to improve image quality. The proposed protocol was tested in phantom and human studies. In vivo scans were performed on 14 healthy subjects and 7 patients with carotid atherosclerosis. Kinetic parameters including area under the concentration versus time curve (AUC), vp, Ktrans, and ve were evaluated for each case.ResultsPhantom experiments showed that T1 measurements using the proposed protocol were in good agreement with reference value (). In vivo studies demonstrated that AUC, vp, and Ktrans in the patient group were significantly higher than in the control group (0.63 ± 0.13 versus 0.42 ± 0.12, P < 0.001; 0.14 ± 0.05 versus 0.11 ± 0.03, P = 0.034; and 0.13 ± 0.04 versus 0.08 ± 0.02, P < 0.001, respectively). Results from repeated subjects showed good interscan reproducibility (intraclass correlation coefficient: vp, 0.83; Ktrans, 0.87; ve, 0.92; AUC, 0.94).ConclusionMultitasking DCE is a promising approach for quantitatively assessing the vascularity properties of the carotid vessel wall.
Whole brain measurements of the positive BOLD response variability during a finger tapping task at 7 T show regional differences in its profiles
Authors: Boillat Yohan , van der Zwaag Wietske 
Published: October 2018

PurposeThe positive BOLD response can vary across brain regions. Here, the positive BOLD responses of motor regions, including the cerebellum, were investigated by fast fMRI acquisition.MethodsThe participants were asked to perform an event‐related finger‐tapping task in a 7T MRI scanner during a fast 3D‐EPI controlled aliasing in parallel imaging acquisition protocol (CAIPI; TR = 399 ms). The positive BOLD responses of 6 motor regions were extracted and their timings and shapes measured.ResultsCompared with other brain regions, the positive BOLD responses in the cerebellum and secondary somatosensory cortex showed delayed onsets, but no differences were observed for the time to‐peak. Additionally, variations of the undershoot and main peak amplitudes were also observed, and undershoot was quasi‐absent in the cerebellum.ConclusionThis study confirms that care should be taken when drawing conclusions about neuronal activity from the BOLD signal, particularly for the cerebellum.