bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous multislice MRI thermometry with a single coil using incoherent blipped‐controlled aliasing
Authors: Quah Kristin , Poorman Megan E. , Allen Steven P. , Grissom William A. 
Published: August 2019

PurposeTo increase volume coverage in real‐time MR thermometry for transcranial MR‐guided focused ultrasound (tcMRgFUS) ablation, without multiple receive coils.Theory and MethodsMultiband excitation and incoherent blipped‐controlled aliasing were implemented in a 2DFT pulse sequence used clinically for tcMRgFUS, and an extended k‐space hybrid reconstruction was developed that recovers slice‐separated temperature maps assuming that heating is focal, given slice‐separated pretreatment images. Simulations were performed to characterize slice leakage, the number of slices that can be simultaneously imaged with low‐temperature error, and robustness across random slice‐phase k‐space permutations. In vivo experiments were performed using a single receive coil without heating to measure temperature precision, and gel phantom FUS experiments were performed to test the method with heating and with a water bath.ResultsSimulations showed that with large hot spots and identical magnitude images on each slice, up to three slices can be simultaneously imaged with less than C temperature root‐mean‐square error. They also showed that hot spots do not alias coherently between slices, and that an average 86% of random slice‐phase k‐space permutations yielded less than C temperature error. Temperature precision was not degraded compared to single‐slice imaging in the in vivo SMS scans, and the gel phantom SMS temperature maps closely tracked single‐slice temperature in the hot spot, with no coherent aliasing to other slices.ConclusionsIncoherent controlled aliasing SMS enables accurate reconstruction of focal heating maps from two or three slices simultaneously, using a single receive coil and a sparsity‐promoting temperature reconstruction.
Preparation and properties of melt‐spun poly(fluorinated ethylene‐propylene)/graphene composite fibers
Authors: Pan Jinfeng , Xiao Changfa , Huang Yan , Zhu Zhengtao 
Published: August 2019

AbstractThe matrix of poly(fluorinated ethylene‐propylene) (FEP) was modified with graphene (GE) as filler, and then the composite fibers were prepared by melt spinning method with a twin‐screw extruder. The effects of both the draw ratio and GE content on the structures and properties of FEP/GE composite fibers were investigated. The results showed that the addition of nanoparticles reduced the crystallization of molecular chains and the orientation of crystalline units in the fibers, while the drafting and heat setting process could effectively improve the crystallinity and orientation of composite fibers. Moreover, the addition of GE improved the mechanical properties of the composite fibers and had no effect on the chemical resistance of the composite fibers. A significant enhancement of mechanical properties of the composite fibers was obtained at low GE content, that, a 35.5% improvement of tensile strength and a 19.5% increase of Young's modulus were achieved at a GE content of only 0.3 wt%. Compared with pure FEP fibers, the oil affinity of composite fibers was also significantly improved. The prepared FEP/GE composite fibers that showed excellent chemical resistance have potential application in oil‐water separation, especially in high temperature resistant fibrous materials.
Challenges in the quality of herbal medicinal products with a specific focus on contaminants
Authors: Steinhoff Barbara 
Published: August 2019

AbstractBackgroundThe complex regulatory framework for the quality of herbal medicinal products, in particular with regard to potential contaminants, consists of legal provisions including Pharmacopoeia requirements, relating to limits as well as in most cases to methods for determination.ObjectiveThis review intends to provide an overview on the legal requirements for testing potential contaminants in herbal drugs used for the production of herbal medicinal products.MethodologyThe following issues are described and discussed:For the assessment of pesticide residues, Chapter 2.8.13 of the European Pharmacopoeia and Regulation (EC) 396/2005 applies, for heavy metals the general Pharmacopoeia monograph as well as the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Q3D guideline on elemental impurities. The Pharmacopoeia also includes limits and acceptance criteria for microbiological purity and aflatoxins, respectively. Polycyclic aromatic hydrocarbons are mentioned in Regulation (EC) 1881/2006 for food as well as in a Reflection Paper on herbal medicinal products. For several years, a potential contamination with pyrrolizidine alkaloids was discussed which led to measures being imposed on industry and health authorities.ResultsVarious examples demonstrate that the evaluation of data from daily analytical practice is extremely useful to gain an overview on the occurrence of residues and/or contaminants in herbal drugs and herbal preparations. Such evaluations might assist manufacturers in their individual risk assessment and the definition of their testing strategies and contribute to guarantee the quality and safety of the marketed products.ConclusionAnnual data evaluations demonstrate that a remarkable decrease of the pyrrolizidine alkaloid content burden in herbal drugs and extracts used for the production of herbal medicinal products has been achieved over the past few years. However, it has also become clear that this issue cannot be completely solved in the near future.
Effect of nanoparticle shape on the conductivity of Ag nanoparticle poly(vinyl alcohol) composite films
Authors: Sirohi Sidhharth , Mittal Avneesh , Nain Ratyakshi , Jain Nishant , Singh Ravinder , Dobhal Saiyam , Pani Balaram , Parida Dambarudhar 
Published: August 2019

AbstractIn this work, the shape effect of silver nanoparticles (AgNPs) on photocatalysis and electrical conductivity was investigated. Different shapes of AgNPs achieved using various concentrations of NaBH4were characterized using particle size analysis, UV–visible spectroscopy and high‐resolution transmission electron microscopy. The colours of colloidal solutions were found to be influenced by the shape of the nanoparticles. Yellow and blue AgNPs were spherical and triangular in shape, respectively, whereas distorted spherical particles showed a red colour and the presence of both particles in one solution resulted in a green colloidal solution. The AgNPs were used to prepare Ag/poly(vinyl alcohol) (PVA) composite films and their electrical conductivity was investigated. Owing to their better charge carrier generation, uniform distribution in the PVA matrix and enhanced surface plasmon resonance, blue AgNPs (triangular shaped) exhibited superior conductivity performance compared to the other nanoparticles. The values for maximum conductivity for the blue and yellow AgNPs were 3.45 × 10−4Ω−1cm−1and 2.67 × 10−4Ω−1cm−1respectively. © 2019 Society of Chemical Industry
Network‐based feature selection reveals substructures of gene modules responding to salt stress in rice
Authors: Du Qian , Campbell Malachy , Yu Huihui , Liu Kan , Walia Harkamal , Zhang Qi , Zhang Chi 
Published: August 2019

AbstractRice, an important food resource, is highly sensitive to salt stress, which is directly related to food security. Although many studies have identified physiological mechanisms that confer tolerance to the osmotic effects of salinity, the link between rice genotype and salt tolerance is not very clear yet. Association of gene co‐expression network and rice phenotypic data under stress has penitential to identify stress‐responsive genes, but there is no standard method to associate stress phenotype with gene co‐expression network. A novel method for integration of gene co‐expression network and stress phenotype data was developed to conduct a system analysis to link genotype to phenotype. We applied aLASSO‐based method to the gene co‐expression network of rice with salt stress to discover key genes and their interactions for salt tolerance‐related phenotypes. Submodules in gene modules identified from the co‐expression network were selected by theLASSOregression, which establishes a linear relationship between gene expression profiles and physiological responses, that is, sodium/potassium condenses under salt stress. Genes in these submodules have functions related to ion transport, osmotic adjustment, and oxidative tolerance. We argued that these genes in submodules are biologically meaningful and useful for studies on rice salt tolerance. This method can be applied to other studies to efficiently and reliably integrate co‐expression network and phenotypic data.
Predicting plasticity‐controlled failure of glassy polymers: Influence of stress‐accelerated progressive physical aging
Authors: Clarijs Coen C. W. J. , Kanters Marc J. W. , van Erp Marco J. , Engels Tom A. P. , Govaert Leon E. 
Published: August 2019

ABSTRACTThis study focuses on the prediction of long‐term failure of glassy polymers under static or cyclic loading conditions, including the role of stress‐accelerated progressive aging. Progressive physical aging plays a dominant role in a polymer's performance under prolonged loading conditions, and to obtain accurate predictions of failure, its effect has to be considered. First, the aging kinetics, as influenced by temperature and stress history, are studied extensively. Similar to an elevated temperature, the application of a stress (below the yield stress) activates the aging process, and as a result, the yield stress will evolve faster in time. The activation by stress appears to be limited; at some stress level, the activation stagnates and is followed by rejuvenation. This evolution is captured in a model by introducing a state parameter, which describes the thermodynamic state of the material and is directly linked to the yield stress. With the aging kinetics included in the model, an accurate prediction of the failure time for cyclic loading conditions is obtained. For static loading conditions, however, the effect of physical aging is overestimated because of the stagnation of the activation by stress. It appears that there are marked differences in the stress level where stagnation and subsequent rejuvenation occur for a cyclic or static load. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1300–1314
HelixJet: An innovative plasma source for next‐generation additive manufacturing (3D printing)
Authors: Schäfer Jan , Quade Antje , Abrams Kerry J. , Sigeneger Florian , Becker Markus M. , Majewski Candice , Rodenburg Cornelia 
Published: August 2019

AbstractA novel plasma source (HelixJet) for use in additive manufacturing (AM)/3D printing is proposed. The HelixJet is a capacitively coupled radio frequency plasma with a double‐helix electrode configuration that generates a surprisingly stable and homogeneous glow plasma at low flow rates of argon and its mixtures at atmospheric pressure. The HelixJet was tested on three polyamide powders usually used to produce parts by laser sintering, a powder‐based AM process, to form local deposits. The chemical composition of such plasma‐printed samples is compared with thermally produced and laser‐sintered samples with respect to differences in morphology that result from the different thermal cycles on several length scales. Plasma prints exhibit unique features attributable to the nonequilibrium chemistry and to the high‐speed heat exchange.
Associations between age, respiratory comorbidities, and dysphagia in infants with down syndrome
Authors: Jackson Arwen , Maybee Jennifer , Wolter‐Warmerdam Kristine , DeBoer Emily , Hickey Francis 
Published: August 2019

AbstractObjectives: Children with Down syndrome (DS) have a high risk of dysphagia and the pediatric pulmonologist may be involved in diagnosis and management. The objective of this study is to evaluate the associations between age, dysphagia, and medical comorbidities in young children with DS. We hypothesized that swallow study findings are more likely to change in younger infants and that medical comorbidities may be associated with dysphagia.Study design: Results of videofluoroscopic swallow studies (VFSS) and fiberoptic endoscopic evaluation of swallowing (FEES) from 2010 to 2016 were collected retrospectively in children with DS with initial swallow study at less than 12 months of age. Results were analyzed for findings and change based on age at initial study, reason for referral, and medical comorbidities.Results: One hundred eleven infants with 247 VFSS and 14 FEES were included. Deep laryngeal penetration and/or aspiration were found in 31.9% of infants less than 6 months and 51.3% of infants 6 to 12 months. Children with initial swallow study performed at greater than or equal to 6 months of age were more likely (80.0%) to have unchanged findings on follow‐up study compared to children imaged at less than 6 months (35.3%). Laryngomalacia, pulmonary hypertension, pneumonia, and congenital cardiac disease were associated with dysphagia.Conclusion: We confirmed that dysphagia is common in infants with DS and comorbidities and provided preliminary evidence that swallow study findings may be more likely to change in children tested under 6 months of age. Providers should consider that results for instrumental swallow studies may change, particularly if the test was completed on a young infant.
Efficient Pulse‐Excitation Techniques for Single Photon Sources from Quantum Dots in Optical Cavities
Authors: Gustin Chris , Hughes Stephen 
Published: August 2019

AbstractRigorous and intuitive master equation models are presented to study on‐demand single photon sources from pulse‐excited quantum dots coupled to optical cavities. Three methods of source excitation are considered: resonant pi‐pulse, off‐resonant phonon‐assisted inversion, and two‐photon excitation of a biexciton–exciton cascade, and the effect of the pulse excitation process on the quantum indistinguishability, efficiency, and purity of emitted photons is investigated. By explicitly modelling the time‐dependent pulsed excitation process in a manner which captures non‐Markovian effects associated with coupling to photon and phonon reservoirs, it is found that photons of near‐unity indistinguishability can be emitted with over 90% efficiency for all these schemes, with the off‐resonant schemes not necessarily requiring polarization filtering due to the frequency separation of the excitation pulse, and allowing for very high single photon purities. Furthermore, the off‐resonant methods are shown to be robust over certain parameter regimes, with less stringent requirements on the excitation pulse duration in particular. Also, a semi‐analytical simplification of the master equation is derived for the off‐resonant drive, which gives insight into the important role that exciton–phonon decoupling for a strong drive plays in the off‐resonant phonon‐assisted inversion process.
Parched pines: a quantitative comparison of two multi‐year droughts and associated mass mortalities of bishop pine (Pinus muricata) on Santa Cruz Island, California
Authors: Taylor Annalise , Biswas Tanushree , Randall John M. , Klausmeyer Kirk , Cohen Brian 
Published: August 2019

AbstractExtreme weather events such as droughts are expected to increase in severity and frequency as the climate changes; it is imperative that land managers be able to monitor associated changes in vegetation health efficiently and across large scales in order to mitigate or prepare for these events. This need motivated deeper study of the die‐off of bishop pine (Pinus muricata) on California's Santa Cruz Island during the 2012–2016 drought. These pines play a keystone role within the island's ecosystem and have experienced two severe droughts and associated mass die‐offs in the past 40 years. In an effort to compare these events, we used meteorological data to track changes in drought severity from 1985 to 2018 coupled with novel methods for forest monitoring to reveal dynamics not detectable by shorter‐duration studies. Leveraging 34 years of 30 m resolution Landsat imagery, we compared vegetation mortality between the two most severe droughts of that time period: 1987–1991 and 2012–2016. We used the slope of decline in the annual median value of three different Vegetation Indices (VIs; NBR, NDMI and NDVI) to compare mortality between the two drought events and to reveal spatial patterns of mortality within the bishop pine forests. Our results indicated that the 2012–2016 drought was the island's harshest in over a century and that it resulted in greater and more widespread mortality of vegetation within bishop pine stands than the 1987–1991 drought. The average VI decline was significantly greater during the 2012–2016 drought than the 1987–1991 drought by a factor of 1.89, 2.09 and 1.84 for NBR, NDMI and NDVI, respectively. Our results aligned with projections of increasing drought severity and associated tree mortality across the region. The temporal monitoring methods developed here can be adapted to study similar landscape scale changes over multiple decades in other forest ecosystems facing similar threats.
Energetic Furazan and Triazole Moieties: A Promising Heterocyclic Cation
Authors: Xiong Hualin , Yang Hongwei , Cheng Guangbin , Zhang Zaichao 
Published: August 2019

AbstractFurazan has rarely been involved in the development of energetic cations. Now a new cation based on furazan and triazole moieties 3‐amino‐4‐(4,5‐diamino‐1, 2, 4‐triazol‐3‐yl)furazan (2) and a series of energetic salts were explored as good thermal stable and insensitive energetic materials. These new salts were further characterized by elemental analysis, infrared and multinuclear NMR spectra. The structures of 3–6 and 8 were supported by single‐crystal X‐ray diffraction. The physicochemical and energetic properties for all synthesized energetic compounds, including density, thermal stability and energetic performance were investigated. The measured density of compounds 2–10 are in the range of 1.65 g cm−3 to 1.84 g cm−3. Compounds 2–10 have good thermal stabilities (197‐272 °C). Based on the measured density and calculated heat of formation, they show good calculated detonation performances (D: 7980 m s−1 to 8883 m s−1, P: 22.6 GPa to 34.8 GPa). More importantly, they exhibit low sensitivities (IS: 20 J to 40 J, FS: 280 N to 360 N).
Cooperative Effect of the Ce–Co‐Ox for the Catalytic Oxidation of Toluene
Authors: Zhang Xuejun , Zhao Jinggang , Song Zhongxian , Zhao Heng , Liu Wei , Ma Zi'ang , Zhao Min , Du Huixian 
Published: August 2019

AbstractPure CeO2, Co3O4 and CeO2‐CoOx catalysts were successfully prepared by co‐precipitation method and investigated for toluene oxidation. The introduction of cobalt improved the porous texture and increased the specific surface area of catalysts. The cooperative effect of Co and Ce was characterized by several techniques. The characterization results indicated that CeO2‐CoOx showed the largest concentration of Ce3+, oxygen vacancy and surface adsorbed oxygen due to the generation of more structural defects, resulting in better redox properties. Hence, CeO2‐CoOx exhibited excellent catalytic activity and ideal CO2 selectivity than pure CeO2 and Co3O4.
Bifunctional Thio/Squaramide Catalyzed Stereoselective Michael Additions of Aldehydes to Nitroalkenes towards Synthesis of Chiral Pyrrolidines
Authors: Ormandyová Kristína , Bilka Stanislav , Mečiarová Mária , Šebesta Radovan 
Published: August 2019

AbstractBifunctional squaramide and thiosquaramide organocatalysts were assessed in a stereoselective Michael addition of aldehydes to nitroalkenes. Organocatalysts feature pyrrolidine unit for enamine activation of aldehydes and hydrogen bond donating fragment for nitroalkene activation. The corresponding Michael adducts were obtained in good yields and good to high enantiomeric purities. Solvent‐free conditions were also tested but did not provide any significant improvement. Michael adducts were transformed into chiral pyrrolidines via reductive cyclization.
Super‐Exchange Interaction Induced Overall Optimization in Ferromagnetic Perovskite Oxides Enables Ultrafast Water Oxidation
Authors: Dai Jie , Zhu Yinlong , Yin Yichun , Tahini Hassan A. , Guan Daqin , Dong Feifei , Lu Qian , Smith Sean C. , Zhang Xiwang , Wang Huanting , Zhou Wei , Shao Zongping 
Published: August 2019

AbstractOxygen evolution reaction (OER) is crucial in many renewable electrochemical technologies including regenerative fuel cells, rechargeable metal–air batteries, and water splitting. It is found that abundant active sites with favorable electronic structure and high electrical conductivity play a dominant role in achieving high electrocatalytic efficiency of perovskites, thus efficient strategies need to be designed to generate multiple beneficial factors for OER. Here, highlighted is an unusual super‐exchange effect in ferromagnetic perovskite oxide to optimize active sites and enhance electrical conductivity. A systematic exploration about the composition‐dependent OER activity in SrCo1x
Rux
O3−δ
(denoted as SCRx) (x = 0.0–1.0) perovskite is displayed with special attention on the role of super‐exchange interaction between high spin (HS) Co3+ and Ru5+ ions. Induced by the unique Co3+–O–Ru5+ super‐exchange interactions, the SCR0.1 is endowed with abundant OER active species including Co3+/Co4+, Ru5+, and O22−/O−, high electrical conductivity, and metal–oxygen covalency. Benefiting from these advantageous factors for OER electrocatalysis, the optimized SCR0.1 catalyst exhibits a remarkable activity with a low overpotential of 360 mV at 10 mA cm−2, which exceeds the benchmark RuO2 and most well‐known perovskite oxides reported so far, while maintaining excellent durability. This work provides a new pathway in developing perovskite catalysts for efficient catalysis.
Oxygen‐Tolerant Hydrogen Peroxide Reduction Catalysts for Reliable Noninvasive Bioassays
Authors: Ding Zhenyao , Chen Liping , Wang Dandan , Zhou Hang , Zhou Lu , Zhu Xing , Jiang Lei , Feng Xinjian 
Published: August 2019

AbstractNoninvasive bioassays based on the principle of a hydrogen peroxide (H2O2) cathodic reaction are highly desirable for low concentration analyte detection within biofluids since the reaction is immune to interference from oxidizable species. However, the inability to selectively reduce H2O2 over O2 for commonly used stable catalysts (carbon or noble metals) is one of the key factors limiting their development and practical applications. Herein, catalysts that enable selective H2O2 reduction in the presence of oxygen with fluctuating concentrations are reported. These catalysts consist of noble metal nanoparticles underneath an amorphous chromium oxide nanolayer, which inhibits O2 diffusion to the metal/oxide interface and suppresses its reduction reaction. Using these catalysts, analytes of low concentration in biofluids, including but not limited to glucose and lactate, are detected within the presence of various interferents. This work enables wide application of the cathodic detection principle and the development of reliable noninvasive bioassays.