bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new analytical method for determination of the nitrogen isotopic composition of methionine: Its application to aquatic ecosystems with mixed resources
Authors: Ishikawa Naoto F. , Chikaraishi Yoshito , Takano Yoshinori , Sasaki Yoko , Takizawa Yuko , Tsuchiya Masashi , Tayasu Ichiro , Nagata Toshi , Ohkouchi Naohiko 
Published: September 2018

AbstractCompound‐specific nitrogen isotope (δ15N) analysis of amino acids is a powerful tool for estimating the trophic positions (TPs) of animals. The TP of an animal can be represented as a linear function of the isotopic difference between glutamic acid (δ15NGlu) and phenylalanine (δ15NPhe). However, the method using δ15NGlu and δ15NPhe cannot be applied to animals in mixed food webs where basal resources are derived from both terrestrial and aquatic primary producers, because the mean value of δ15NPhe relative to δ15NGlu differs greatly between terrestrial plants (+8.4‰) and aquatic algae (−3.4‰). To resolve this problem, the δ15N of methionine (δ15NMet) is useful. Because the C–N bond of methionine is not cleaved in its initial metabolic step, theoretically there should be little diversity in δ15NMet relative to δ15NGlu among primary producers and a small trophic discrimination factor for methionine in animal metabolism. We developed a dual‐column‐coupled GC‐C‐IRMS method to determine δ15NMet. Data collected from controlled feeding experiments and wild samples demonstrated that the isotopic difference between methionine and phenylalanine in terrestrial food webs (ΔMet−Phe = −16.5 ± 0.5‰) is clearly distinguishable from that in aquatic food webs (ΔMet−Phe = −5.0 ± 0.5‰). This approach allowed us to determine ecologically reasonable TP values for carnivores in a stream food web, which were substantially underestimated with the conventional method. This method has potential utility in assessing TP for animals that rely on varying proportions of both terrestrial‐ and aquatic‐derived resources, with no requirement to characterize δ15N in their basal resources.
High‐resolution imaging particle analysis of freshwater cyanobacterial blooms
Authors: Graham M. D. , Cook J. , Graydon J. , Kinniburgh D. , Nelson H. , Pilieci S. , Vinebrooke R. D. 
Published: September 2018

AbstractEffective assessment of the health risk of cyanobacterial blooms requires an early warning system, which enables rapid detection of species of concern and determination of whether their cell concentrations exceed advisory guidelines. Advanced digital flow cytometry using FlowCam® (Fluid Imaging Technologies) in combination with light microscopy is a solid prospect for tracking cyanobacterial communities in a timely manner. However, implementation of such a method poses several challenges for the user. We first address sample preparation, instrumentation, taxonomic enumeration, and trouble‐shooting to facilitate high throughput of analyses of water samples for total cyanobacterial cell counts and their species composition. Preservation and initial screening of samples using light microscopy to estimate community size structure are endorsed to insure their archival quality and avoid clogging of the flow cell. We show that the highest magnification (×20 objective) is needed to achieve representative total and species‐specific cell enumerations. We also report that total cyanobacterial cell counts for samples analyzed using FlowCam vs. inverted light microscopy show significant positive correlation, as do those for preserved vs. live samples. Quantification of community composition using FlowCam vs. light microscopy also shows strong concordance. Although our FlowCam method performs well in the context of the World Health Organization advisory threshold of a total cyanobacterial count of 100,000 cells mL−1, it remains a work in progress in terms of reliably automated species‐level identifications.
THE CRUCIAL ROLE OF TALENT IN ORGANIZATIONAL PERFORMANCE
Authors: Lewis Clinton 
Published: September 2018

AbstractLewis Jr., a senior executive at Zoetis, a global animal health company, believes the success of a leader hinges on “the ability to attract, develop and retain talented people.” In assessments for a position of greater responsibility, he looks at various factors, which involve a wide range of people: “In assessing my people, I look at their mind‐set, capabilities, and the consistency of their performance—and to that end, I also look at the quality of their team.” He observes the rigor with which his team members develop their own teams, and points out that they “need to develop a robust and diverse talent pipeline lower in the organization, from which we can draw our next generation of leadership.”
Tannic Acid Physically Cross‐Linked Responsive Hydrogel
Authors: Zheng Lu‐Yi , Shi Jing‐Min , Chi Yan‐Hui 
Published: September 2018

AbstractTannic acid (TA) is a polyphenol‐rich compound found in many natural plants. There are large numbers of phenolic hydroxyls at the terminal of the TA molecule, being capable of forming hydrogen bonds with hydrogen‐bonding donating polymers such as polyvinylpyrrolidone (PVP) and then engineering a hydrogel network. The reversible switch between phenolic hydroxyls and quinones tuned by pH affords the dynamic nature of the resultant hydrogen bonds. The gels exhibit excellent shear‐thinning and self‐recovery properties. Moreover, the polyphenols can form coordinates with Fe(III) that link different TAs to form a hydrogel network. Hence, adding Fe(III) solution to the TA‐PVP sol can form additional interactions inside the TA‐PVP gel. The easy preparation of the dual‐responsive gels with nontoxic raw materials may allow for its application in the biomedical field.
SPION‐Decorated Nanofibers by RAFT‐Mediated Free Radical Emulsion Polymerization‐Induced Self Assembly
Authors: Nguyen Duc , Huynh Vien , Pham Nguyen , Pham Binh , Serelis Algirdas , Davey Tim , Such Chris , Hawkett Brian 
Published: September 2018

AbstractRAFT‐mediated free‐radical emulsion polymerization is successfully used to synthesize polystyrene nanofibers using triblock amphiphilic macro‐RAFT copolymers as stabilizers. The polymerization is under RAFT control, producing various morphologies from spherical particles, nanofibers, nanoplatelets, and polymer vesicles. Optimum conditions are established for the synthesis of predominantly negatively charged polymer nanofibers. Superparamagnetic iron oxide nanoparticles (SPION)‐decorated nanofibers are formed by simple mixing of the SPIONs with the fibers at an appropriate pH. The composite material has been found to be superparamagnetic and could be aligned under a magnetic field.
Polymer Nanospheres with Hydrophobic Surface Groups as Supramolecular Building Blocks Produced by Aqueous PISA
Authors: Ebeling Bastian , Belal Khaled , Stoffelbach François , Woisel Patrice , Lansalot Muriel , D'Agosto Franck 
Published: September 2018

AbstractA robust and straightforward synthesis of waterborne polymer nanospheres bearing the supramolecular association unit dialkoxynapthalene at their surface is presented using polymerization‐induced self‐assembly (PISA). A RAFT agent bearing this unit is first employed to produce poly(acrylic acid) chains, which are then chain‐extended with styrene (S) to spontaneously form the nano‐objects via RAFT aqueous emulsion polymerization. The particular challenge posed by the dialkoxynapthalene hydrophobicity can be overcome by the use of PISA and the deprotonation of the poly(acrylic acid). At pH = 7, very homogeneous latexes are obtained. The particle diameters can be tuned from 36 to 105 nm (with a narrow particle size distribution) by varying the molar mass of the PS block. The surface accessibility of the dialkoxynapthalene moieties is demonstrated by complexation with the complementary host cyclobis(paraquat‐p‐phenylene) (CBPQT4+ · Cl−), highlighting the potential of the nanospheres to act as building blocks for responsive supramolecular structures.
CH Activation as a Shortcut to Conjugated Polymer Synthesis
Authors: Blaskovits J. Terence , Leclerc Mario 
Published: September 2018

AbstractDirect (hetero)arylation polymerization exploits the palladium‐catalyzed activation of aromatic CH bonds for the atom‐economical synthesis of conjugated polymers for a wide range of applications. This account outlines how direct arylation methodologies overcome many of the limitations of contemporary polymerization techniques at both the research and production scale, and explains how monomer design and reaction conditions must be tailored to ensure high polymer molecular weight, yield, and structural integrity. Current research aims to improve further this reaction's profile as a sustainable methodology while at the same time making it competitive with the Migita–Stille and Miyaura–Suzuki polymerizations both in scope of accessible structures and synthetic efficiency. This feature article charts the recent developments and future directions of CH activation research as it moves toward becoming at once an industrially feasible, environmentally friendly, and synthetically powerful polymerization technique.
Sulfur Polymers Meet Poly(ionic liquid)s: Bringing New Properties to Both Polymer Families
Authors: Gomez Iñaki , De Anastro Asier Fdz , Leonet Olatz , Blazquez Jose Alberto , Grande Hans‐Jürgen , Pyun Jeffrey , Mecerreyes David 
Published: September 2018

AbstractSulfur‐containing polymers and poly(ionic liquid)s are emerging macromolecules with unique properties and applications. This article shows the first integration of these two polymer families, leading to materials with a unique combination of properties. The synthetic strategy toward sulfur‐containing poly(ionic liquid)s involves first the copolymerization of elemental sulfur with 4‐vinylbenzyl chloride and subsequent quaternization of the alkyl chloride group using N‐methyl imidazole. The synthetic pathway is completed by the anion exchange reaction of the poly(sulfur‐co‐4‐vinylbenzyl imidazolium chloride) by a sulphonamide anion. The obtained polymers are fully characterized by NMR, FTIR, SEC, DSC, and TGA. The sulfur poly(ionic liquid)s combine some properties related to its poly(ionic liquid) nature, such as anion‐dependent solubility (water vs organic solvents) and high ionic conductivity as well as properties related to its sulfur content, such as redox activity.
Compressed‐Sensing MP2RAGE sequence: Application to the detection of brain metastases in mice at 7T
Authors: Trotier Aurélien J. , Rapacchi Stanislas , Faller Thibaut L. , Miraux Sylvain , Ribot Emeline J. 
Published: September 2018

PurposeTo develop a Compressed Sensing (CS)‐MP2RAGE sequence to drastically shorten acquisition duration and then detect and measure the T1 of brain metastases in mice at 7 T.MethodsThe encoding trajectory of the standard Cartesian MP2RAGE sequence has been modified (1) to obtain a variable density Poisson disk under‐sampling distribution along the ky‐kz plane, and (2) to sample the central part of the k‐space exactly at TI1 and TI2 inversion times. In a prospective study, the accuracy of the T1 measurements was evaluated on phantoms containing increasing concentrations of gadolinium. The CS acceleration factors were increased to evaluate their influence on the contrast and T1 measurements of brain metastases in vivo. Finally, the 3D T1 maps were acquired with at 4‐fold increased spatial resolution. The volumes and T1 values of the metastases were measured while using CS to reduce scan time.ResultsThe implementation of the CS‐encoding trajectory did not affect the T1 measurements in vitro. Accelerating the acquisition by a factor of 2 did not alter the contrast or the T1 values of the brain metastases. 3D T1 maps could be obtained in < 1 min using a CS factor of 6. Increasing the spatial resolution enabled more accurately measurement of the metastasis volumes while maintaining an acquisition duration below 5 min.ConclusionThe CS‐MP2RAGE sequence could be of great interest in oncology to either rapidly obtain mouse brain 3D T1 maps or to increase the spatial resolution with no penalty on the scan duration.
Hyperpolarized 13C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
Authors: Wang Jiazheng , Hesketh Richard L. , Wright Alan J. , Brindle Kevin M. 
Published: September 2018

Hyperpolarized MRI with 13C‐labeled metabolites has enabled metabolic imaging of tumors in vivo. The heterogeneous nature of tumors and the limited lifetime of the hyperpolarization require high resolution, both temporally and spatially. We describe two sequences that make more efficient use of the 13C polarization than previously described single‐shot 3D sequences. With these sequences, the target metabolite resonances were excited using spectral‐spatial pulses and the data acquired using spiral readouts from a series of echoes created using a fast‐spin‐echo sequence employing adiabatic 180° pulses. The third dimension was encoded with blipped gradients applied in an interleaved order to the echo train. Adiabatic inversion pulses applied in the absence of slice selection gradients allowed acquisition of signal from odd echoes, formed by unpaired adiabatic pulses, as well as from even echoes. The sequences were tested on tumor‐bearing mice following intravenous injection of hyperpolarized [1‐13C]pyruvate. [1‐13C] pyruvate and [1‐13C] lactate images were acquired in vivo with a 4 × 4 × 2 cm3 field of view and a 32 × 32 × 16 matrix, leading to a nominal resolution of 1.25 × 1.25 × 1.25 mm3 and an effective resolution of 1.25 × 1.25 × 4.5 mm3 when the z‐direction point spread function was taken into account. The acquisition of signal from more echoes also allowed for an improvement in the signal‐to‐noise ratio for resonances with longer T2 relaxation times. The pulse sequences described here produced hyperpolarized 13C images with improved resolution and signal‐to‐noise ratio when compared with similar sequences described previously.
Very high‐order accurate finite volume scheme for the convection‐diffusion equation with general boundary conditions on arbitrary curved boundaries
Authors: Costa Ricardo , Nóbrega João M. , Clain Stéphane , Machado Gaspar J. , Loubère Raphaël 
Published: September 2018

SummaryObtaining very high‐order accurate solutions in curved domains is a challenging task as the accuracy of discretization methods may dramatically reduce without an appropriate treatment of boundary conditions. The classical techniques to preserve the nominal convergence order of accuracy, proposed in the context of finite element and finite volume methods, rely on curved mesh elements, which fit curved boundaries. Such techniques often demand sophisticated meshing algorithms, cumbersome quadrature rules for integration, and complex nonlinear transformations to map the curved mesh elements onto the reference polygonal ones. In this regard, the reconstruction for off‐site data method, proposed in the work of Costa et al, provides very high‐order accurate polynomial reconstructions on arbitrary smooth curved boundaries, enabling integration of the governing equations on polygonal mesh elements, and therefore, avoiding the use of complex integration quadrature rules or nonlinear transformations. The method was introduced for Dirichlet boundary conditions and the present article proposes an extension for general boundary conditions, which represents an important advance for real context applications. A generic framework to compute polynomial reconstructions is also developed based on the least‐squares method, which handles general constraints and further improves the algorithm. The proposed methods are applied to solve the convection‐diffusion equation with a finite volume discretization in unstructured meshes. A comprehensive numerical benchmark test suite is provided to verify and assess the accuracy, convergence orders, robustness, and efficiency, which proves that boundary conditions on arbitrary smooth curved boundaries are properly fulfilled and the nominal very high‐order convergence orders are effectively achieved.
Pregnancy course and outcomes in mosaic trisomy 16 confined to the placenta: A case series
Authors: Donato Xavier‐Côme , Brechard Marie‐Pierre , François‐Renard Pauline , Hairion Dominique , Quarello Edwin , Hoffet Médéric , Katsogiannou Maria , Desbriere Raoul 
Published: September 2018

What's already known about this topic?

T16 CPM is correlated with increased occurrence of intrauterine growth restriction.
Feto‐maternal outcomes of T16 CPM have no predictable pattern, making pregnancy management challenging.
What does this study add?

Intrauterine growth restriction and very low PAPP‐A levels with or without first‐trimester risk <1/250 and, a fortiori, association with placental abnormalities should be indicators for chorionic villus sampling.
Cases should be closely monitored with serial ultrasounds for fetal growth and Doppler flows, FHR and maternal arterial pressure.
Potential therapeutics of Alzheimer's diseases: New insights into the neuroprotective role of trehalose‐conjugated beta sheet breaker peptides
Authors: Di Natale G. , Zimbone S. , Bellia F. , Tomasello M.F. , Giuffrida M.L. , Pappalardo G. , Rizzarelli E. 
Published: September 2018

AbstractAlzheimer's disease (AD) is a progressive neurodegenerative disease with no cure. The conversion of the amyloid‐β (Aβ) peptide into soluble oligomers has recently become recognized as playing a key role in AD pathogenesis. Thus, prevention and therapeutic strategies against AD focus on modulating Aβ levels aiming also at stabilizing Aβ's monomeric status or inhibiting the peptide's self‐assembly. Peptide‐based inhibitors may provide a reasonable alternative to chemical small molecules. We report herein further insights into the neuroprotective action of two trehalose‐conjugated peptides able to counteract the Aβ's oligomers associated neuronal toxicity. In addition, the Trehalose‐Succinyl‐LPFFD‐NH2 (Th‐Succ‐LPFFD‐NH2) and Ac‐LPFFD‐Trehalose (Ac‐LPFFD‐Th) derivatives protect neuronal cells from excitotoxic insult mediated by NMDA and evoke by themselves pro‐survival signal pathways as an additional cell protective action. UHPLC‐HRMS experiments suggest that a possible step associated to the neuroprotective mechanism involves the cell uptake and/or a membrane interaction of the studied peptides.
Dual‐Responsive Polydimethylsiloxane Networks
Authors: Giebler Michael , Radl Simone Viola , Ast Markus , Kaiser Simon , Griesser Thomas , Kern Wolfgang , Schlögl Sandra 
Published: September 2018

ABSTRACTExploiting the salient features of o‐nitrobenzyl chemistry, this work aims at the preparation of polydimethylsiloxane networks that undergo well‐defined bond cleavage in response to either UV light or different pH values as external trigger. Polydimethylsiloxane (PDMS) oligomers with terminal anhydride groups are thermally crosslinked in the presence of a bi‐functional epoxy monomer containing a photolabile o‐nitrobenzyl ester (o‐NBE) group. The susceptibility of the ester groups toward hydrolytic cleavage reactions is used for a pH‐triggered network degradation. Sol–gel analysis confirms that the degradation time can be easily controlled by the base concentration over different time scales varying between hours and weeks. Along with classical ester hydrolysis, photoinduced degradation of the elastomeric networks is carried out by photoisomerization and cleavage of the o‐NBE links upon exposure with UV light. Positive‐tone patterns with a structure size of 100 μm are obtained by photolithographic techniques confirming the spatial control of solubility properties. However, by increasing the exposure dose, recrosslinking of the networks is observed due to side reactions of the primary photocleavage products. As the reformed crosslinks are less sensitive to ester hydrolysis, the side reactions are employed to inscribe negative‐tone microstructures in the PDMS network. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2319–2329
Synthesis of RAFT‐Mediated Amphiphilic Graft Copolymeric Micelle Using Dextran and Poly (Oleic Acid) toward Oral Delivery of Nifedipine
Authors: Karmakar Puja Das , Seesala Venkata Sundeep , Pal Aniruddha , Dhara Santanu , Chatterjee Soumit , Pal Sagar 
Published: September 2018

ABSTRACTA novel, pH‐responsive supramolecular graft copolymeric micelle, composed of dextran and poly (oleic acid), has been synthesized through reversible addition fragmentation chain transfer polymerization with controlled Mn and narrow polydispersity. The structural properties of the copolymer have been studied using FTIR and 1H NMR spectral analyses. Critical micelle concentration (CMC) has been determined fluorometrically and conductometrically. The copolymer shows pH responsive micellar stability, which has been confirmed using DLS study. Dextran‐g‐OA copolymer demonstrates spherical morphology at CMC, while rod‐like assembly has been evidenced beyond CMC that is probably because of the structural alteration of copolymeric chains at higher copolymer concentration. Dextran‐g‐OA is noncytotoxic toward MG‐63 cells. As the self‐assemble nature of copolymer micelle promotes the oral administration of hydrophobic drugs, nifedipine (NFD, a hydrophobic drug) has been used as model drug that has been encapsulated substantially into the core of the micelle. The copolymer releases the loaded NFD at a much slower rate in simulated gastric fluid (pH 1.2) and relatively faster in simulated intestinal fluid (pH 7.4) with a cumulative release of ~95% within 24 h, suggesting an ideal candidate as nifedipine carrier. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2354–2363
Associations between gait speed and well‐known fall risk factors among community‐dwelling older adults
Authors: Kyrdalen Ingebjørg Lavrantsdatter , Thingstad Pernille , Sandvik Leiv , Ormstad Heidi 
Published: September 2018

AbstractBackground and PurposeExercise interventions are effective at preventing falls in community‐dwelling older adults, especially before disability is present. Gait speed below 1.0 m/s is a strong predictor for falls in the elderly. However, evidence is sparse for gait speed alone being sufficient to identify individuals at a high risk of falling. This study aimed to describe the prevalence of fall risk factors among community‐dwelling older adults in their late 70s and to investigate the associations between these risk factors and low gait speed in this population.MethodsThis cross‐sectional cohort study comprised 108 elderly living in a small Norwegian municipality, born between 1936 and 1938. Exclusion criteria were living in residential care, inability to walk 4 m, and severe cognitive impairment. Measurements included gait speed, depressive symptoms, executive functions, fear of falling, vision function, fall history, body mass index, medications, and comorbidity. Gait speed was dichotomized using a cut‐off of 1 m/s, and associations between different risk factors and low gait speed was explored using logistic regression analysis.ResultsMean gait speed was 1.0 ± 0.3 m/s. In 44.4% of the participants, gait speed was below 1.0 m/s, indicating increased fall risk. Low gait speed was significantly associated with a history of multiple falls (odds ratio [OR] = 3.70, 95% CI [1.18, 11.65]), low educational level (OR = 3.58, 95% CI [1.10, 11.66]), higher number of medications (OR = 4.28, 95% CI [1.63, 11.2]), and higher number of depressive symptoms (OR = 1.31, 95% CI [1.09, 1.58]). We found no significant associations between gait speed and comorbidity, sex, vision, executive functions, or fear of falling.ConclusionOur results indicate that gait speed with cut‐off 1.0 m/s could represent a useful tool for identifying individuals who are vulnerable but not yet disabled and could benefit from fall‐preventive exercise. However, extended assessment is probably needed to personalize interventions.