bluuebunny/crossref_metadata_2025_split huggingface dataset:
ARTEMIS observations of the solar wind proton scattering function from lunar crustal magnetic anomalies
Authors: Poppe A. R. , Halekas J. S. , Lue C. , Fatemi S. 
Published: April 2017

AbstractDespite their small scales, lunar crustal magnetic fields are routinely associated with observations of reflected and/or backstreaming populations of solar wind protons. Solar wind proton reflection locally reduces the rate of space weathering of the lunar regolith, depresses local sputtering rates of neutrals into the lunar exosphere, and can trigger electromagnetic waves and small‐scale collisionless shocks in the near‐lunar space plasma environment. Thus, knowledge of both the magnitude and scattering function of solar wind protons from magnetic anomalies is crucial in understanding a wide variety of planetary phenomena at the Moon. We have compiled 5.5 years of ARTEMIS (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun) observations of reflected protons at the Moon and used a Liouville tracing method to ascertain each proton's reflection location and scattering angles. We find that solar wind proton reflection is largely correlated with crustal magnetic field strength, with anomalies such as South Pole/Aitken Basin (SPA), Mare Marginis, and Gerasimovich reflecting on average 5–12% of the solar wind flux while the unmagnetized surface reflects between 0.1 and 1% in charged form. We present the scattering function of solar wind protons off of the SPA anomaly, showing that the scattering transitions from isotropic at low solar zenith angles to strongly forward scattering at solar zenith angles near 90°. Such scattering is consistent with simulations that have suggested electrostatic fields as the primary mechanism for solar wind proton reflection from crustal magnetic anomalies.
e‐POP RRI provides new opportunities for space‐based, high‐frequency radio science experiments
Authors: Burrell Angeline G. 
Published: April 2017

AbstractPerry et al. (2016, https://doi.org/10.1002/2017JG003855) present the first results of the Radio Receiver Instrument (RRI), a part of the enhanced Polar Outflow Probe (e‐POP) that flies on board the CAScade, Smallsat and IOnospheric Polar Explorer satellite. Using a matched filter technique, e‐POP RRI was able to observe individual radio pulses transmitted by a ground‐based radar. These results were used to examine the temporal variations in the dispersion, polarization, and power of the pulses, demonstrating the capacity for e‐POP RRI to contribute to studies of radio propagation at high‐frequency (HF) ranges. Understanding radio propagation in the presence and absence of ionospheric irregularities is crucial for ionospheric physics, as well as commercial and military radio applications. Conjunctions between e‐POP RRI and ground‐ or space‐based HF transmitters offer a new opportunity for coherent scatter experiments.
Metal‐Catalyzed Synthesis of Functionalized 1,2,4‐Oxadiazoles from Silyl Nitronates and Nitriles
Authors: Nikodemiak Paul , Koert Ulrich 
Published: April 2017

AbstractThe metal‐catalyzed cycloaddition of silyl nitronates and nitriles leading to 1,2,4‐oxadiazoles is described. Silver(I) triflate (AgOTf) and and ytterbium(III) triflate [Yb(OTf)3] are suitable catalysts. A variety of functional groups is tolerated in the nitrile. The reaction works well for alkenyl and aryl silyl nitronates while the use of alkyl silyl nitronates is less efficient. Mechanistic studies are in favour of an elimination of tert‐butyl(dimethyl)silanol (TBSOH) after the cycloaddition step. The new approach has also been applied for the synthesis of the drug ataluren.magnified image
Hydrogen Bonding‐Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l‐1,2‐Diols with Chiral Nucleophilic Catalysts
Authors: Fujii Kazuki , Mitsudo Koichi , Mandai Hiroki , Suga Seiji 
Published: April 2017

AbstractAn extremely efficient acylative kinetic resolution of d,l‐1,2‐diols in the presence of only 0.5 mol% of binaphthyl‐based chiral N,N‐4‐dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert‐alcohol unit(s) of the catalyst and the 1,2‐diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2‐diols with high selectivity factors. The kinetic resolution of d,l‐hydrobenzoin and trans‐1,2‐cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 °C); (iii) high substrate concentration (1.0 M); and (iv) short reaction time (30 min).magnified image
Mild Cobalt(III)‐Catalyzed C–H Hydroarylation of Conjugated C=C/C=O Bonds
Authors: Li Jie , Zhang Zhao , Ma Wenbo , Tang Mengyao , Wang Dawei , Zou Liang‐Hua 
Published: April 2017

AbstractAn efficient cobalt(III)‐catalyzed C‐2‐selective indole C–H hydroarylation of acrolein, enones, and glyoxylates was achieved under mild reaction conditions. The versatile cobalt(III) catalyst displayed excellent positional selectivity with the assistance of pyrimidinyl, pyridyl, and pyrazolyl directing groups, thus overcoming the inherent C‐3 selectivity of an electrophilic indole derivatization. This approach provides an expedient route to indolyl‐substituted aldehydes, ketones, and esters with wide functional group tolerance. In addition, it also features high step‐ and atom‐economy.magnified image
Case‐control study on occupational exposure to extremely low‐frequency electromagnetic fields and glioma risk
Authors: Carlberg Michael , Koppel Tarmo , Ahonen Mikko , Hardell Lennart 
Published: April 2017

BackgroundExposure to extremely low‐frequency electromagnetic fields (ELF‐EMF) was in 2002 classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer at WHO.MethodsLife time occupations were assessed in case‐control studies during 1997‐2003 and 2007‐2009. An ELF‐EMF Job‐Exposure Matrix was used for associating occupations with ELF exposure (μT). Cumulative exposure (μT‐years), average exposure (μT), and maximum exposed job (μT) were calculated.ResultsCumulative exposure gave for astrocytoma grade IV (glioblastoma multiforme) in the time window 1‐14 years odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.4‐2.6, p linear trend <0.001, and in the time window 15+ years OR = 0.9, 95%CI = 0.6‐1.3, p linear trend = 0.44 in the highest exposure categories 2.75+ and 6.59+ μT years, respectively.ConclusionAn increased risk in late stage (promotion/progression) of astrocytoma grade IV for occupational ELF‐EMF exposure was found.
Effective BI‐DIME Ligand for Suzuki–Miyaura Cross‐Coupling Reactions in Water with 500 ppm Palladium Loading and Triton X
Authors: Patel Nitinchandra D. , Rivalti Daniel , Buono Frederic G. , Chatterjee Arindom , Qu Bo , Braith Stefan , Desrosiers Jean‐Nicolas , Rodriguez Sonia , Sieber Joshua D. , Haddad Nizar , Fandrick Keith R. , Lee Heewon , Yee Nathan K. , Busacca Carl A. , Senanayake Chris H. 
Published: April 2017

AbstractAn efficient, sustainable, and broadly applicable procedure has been developed for Suzuki–Miyaura cross‐coupling reactions in environmentally benign solvent (water) by employing as little as 500 ppm Pd(OAc)2 with a monophosphorus BI‐DIME ligand in the presence of inexpensive and commercially available nonionic surfactant Triton X‐100. This method was applied to a broad range of functionalized reaction partners, thereby affording excellent yields of the coupling products, including active pharmaceutical ingredients (APIs). An interesting kinetic study by using reaction calorimetry is also presented, which describes the effect of reaction parameters that enabled the low catalyst loading.
A Convergent Synthesis of the Triterpene Saponin Asiaticoside
Authors: Shao Wenbo , Cao Xin , Shen Lei , Zhang Fuyi , Yu Biao 
Published: April 2017

AbstractAsiaticoside (1), namely, 2α,3β,23‐trihydroxy‐urs‐12‐en‐28‐oic‐O‐α‐l‐rhamnopyranosyl‐(1→4)‐β‐d‐glucopyranosyl‐(1→6)‐β‐d‐glucopyranoside, the major active biomarker of the traditional medicinal plant Centella asiatica, has been synthesized for the first time. The strategy features a late‐stage gold(I)‐catalyzed glycosidic condensation of a triterpenoid acid and a trisaccharide ortho‐hexynylbenzoate. The overall preparation required a total 31 steps with the longest linear sequence occurring over 14 steps in a 6 % overall yield and starting from ursolic acid (3β‐hydroxy‐urs‐12‐en‐28‐oic acid).
A New Benzodithiophene‐Based Cruciform Electron‐Donor–Electron‐Acceptor Molecule with Ambipolar/Photoresponsive Semiconducting and Red‐Light‐Emissive Properties
Authors: Wang Zhijie , Liu Zitong , Gao Zhenhua , Yang Sifen , Wang Yuancheng , Zhang Guanxin , Zhao Yongsheng , Zhang Deqing 
Published: April 2017

AbstractThe rational design of multifunctional materials with both emissive and semiconducting properties remains a challenge. A multifunctional cruciform donor–acceptor (D–A) molecule, 2,2′‐(((4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)bis(thiophene‐5,2‐diyl))bis(methanylylidene))dimalononitrile (BDTTM), which contains a benzodithiophene as the central core, has been synthesized and, based on the output and transfer characteristics of the corresponding FETs, thin films of BDTTM exhibited ambipolar semiconducting behavior. Notably, FETs with thin films of BDTTM showed a photoresponse in both p‐ and n‐channels, and drain‐source‐current enhancement under white‐light irradiation could be detected, even at a low light intensity of 0.1 mW cm−2. Furthermore, BDTTM exhibited red‐light emission both in solution and as a crystalline solid. A microplate of BDTTM with red‐light emission displayed typical optical waveguiding behavior.
Elasticity of the Transition State Leading to an Unexpected Mechanical Stabilization of Titin Immunoglobulin Domains
Authors: Yuan Guohua , Le Shimin , Yao Mingxi , Qian Hui , Zhou Xin , Yan Jie , Chen Hu 
Published: April 2017

AbstractThe giant protein titin plays a critical role in regulating the passive elasticity of muscles, mainly through the stochastic unfolding and refolding of its numerous immunoglobulin domains in the I‐band of sarcomeres. The unfolding dynamics of titin immunoglobulin domains at a force range greater than 100 pN has been studied by atomic force microscopy, while that at smaller physiological forces has not been measured before. By using magnetic tweezers, it is found that the titin I27 domain unfolds in a surprising non‐monotonic force‐dependent manner at forces smaller than 100 pN, with the slowest unfolding rate occurring around 22 pN. We further demonstrate that a model with single unfolding pathway taking into account the elasticity of the transition state can reproduce the experimental results. These results provide important novel insights into the regulation mechanism of the passive elasticity of muscle tissues.
Size‐Tunable Photothermal Germanium Nanocrystals
Authors: Sun Wei , Zhong Grace , Kübel Christian , Ali Feysal M. , Qian Chenxi , Wang Lu , Ebrahimi Manuchehr , Reyes Laura M. , Helmy Amr S. , Ozin Geoffrey A. 
Published: April 2017

AbstractGermanium nanocrystals (ncGe) have not received as much attention as silicon nanocrystals (ncSi). However, Ge has demonstrated superiority over Si nanomaterials in some applications. Examples include, high charge–discharge rate lithium‐ion batteries,[1] small band‐gap opto‐electronic devices,[2] and photo‐therapeutics.[3] When stabilized in an oxide matrix (ncGe/GeOx), its high charge‐retention has enabled non‐volatile memories.[4] It has also found utility as a high‐capacity anode material for Li‐ion batteries with impressive stability.[5] Herein, we report an organic‐free synthesis of size‐controlled ncGe in a GeOx matrix as well as freestanding ncGe, via the thermal disproportionation of GeO prepared from thermally induced dehydration of Ge(OH)2. The photothermal effect of ncGe, quantified by Raman spectroscopy, is found to be size dependent and superior to ncSi. This advance suggests applications of ncGe in photothermal therapy, desalination, and catalysis.
Relationship between degree of polymerization and optical and thermal properties of fluorene in polycarbonate polymers
Authors: Kato Noriyuki , Ikeda Shinya , Hirakawa Manabu , Ito Hiroshi 
Published: April 2017

ABSTRACTThe influences of average degree of polymerization (Dp) and terminal group on thermal and optical properties of high refractive indexed transparent polymers were investigated. In this study, 9,9‐bis[4–(2‐hydroxyethoxy) phenyl] fluorene (BPEF) homo polymer was selected because it has been used as a representative monomer in high refractive index polymers as well as its unique property. BPEF has stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxyl‐terminated polymer, the refractive index (nd) decreased with increasing Dp. On the other hand, for a phenolic‐terminated group, nd increased with increasing Dp, and both converged to same value in high Dp region. As for glass transition temperatures (Tg), both terminal group series were increased as Dp increased. Though Tg of hydroxyl‐terminated polymer was higher than that of phenolic‐terminated polymer in the low Dp region, both converged to the same value and the inverse number of Tg had linear correlation against the weight percentage of carbonyl groups (CO), which was calculated by Dp. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45042.
Physical and tensile properties of epoxy laminated magnetic bacterial cellulose nanocomposite films
Authors: Mashkour Mahdi , Moradabadi Zahra , Khazaeian Abolghasem 
Published: April 2017

ABSTRACTDespite many potential applications, the adverse impacts of magnetic nanoparticles on the tensile properties of magnetic cellulose papers and films are well established. On the other hand, water absorption and thickness swelling of cellulose materials are important limiting factors in many engineering applications. These challenges caused limited applications of magnetic cellulose nanocomposites. The aim of this study is to examine the possibility of modifying the physical and mechanical behaviors of magnetic bacterial cellulose films by epoxy resin lamination. Results showed that the tensile modulus and strength of the magnetic bacterial cellulose film, respectively, increased about 280% and 240% after epoxy lamination while they maintained their desirable magnetic and flexibility properties. Furthermore, the water absorption and thickness swelling of the epoxy laminated magnetic nanocomposite films, respectively, improved about 43% and 42%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45118.
Nonthermal gelation of whey proteins induced by organic acids
Authors: Queirós Ana S. , Lopes‐da‐Silva José A. 
Published: April 2017

ABSTRACTGelation of native whey proteins induced by organic acids at ambient temperature was investigated by fundamental small‐deformation oscillatory rheology. Gelling capability, gelation time, and final viscoelastic properties of the gel were dependent on type of acid, protein and acid concentrations, and pH value. Increasing organic acid concentration or increasing the pH (below pI) resulted in lower gelation times and higher gel modulus values. Differential scanning calorimetry demonstrated that the presence of acetic acid significantly reduced denaturation temperature and enthalpy implying a destabilization effect of the protein structure against thermal unfolding, contrarily to what was observed in the presence of HCl at similar pH values. The gelling ability and the denaturing effectiveness of the acids increase with increasing chain length of the alkyl chain, thus suggesting an important contribution of hydrophobic effects promoting denaturation and fostering the establishment of new interactions between the proteins leading to a nonthermal gelation process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45134.
Synthesis, characterization, and properties of thermosets based on the cocuring of an acetylene‐terminated liquid‐crystal and silicon‐containing arylacetylene oligomer
Authors: Han Mengna , Guo Kangkang , Wang Fan , Zhu Yaping , Qi Huimin 
Published: April 2017

ABSTRACTA thermotropic acetylene‐terminated liquid‐crystal monomer, 2‐methyl‐1,4‐phenylene bis(4‐ethynylbenzoate) (MPBE), was prepared and used as a modification composition to react and cocure with a silicon‐containing arylacetylene (PSA) oligomer for improving PSA resin. The curing behavior of the PSA–MPBE resins were characterized by differential scanning calorimetry and Fourier transform infrared spectroscopy. The microstructure and morphology of the PSA–MPBE resins were investigated by scanning electron microscopy (SEM) and transmission electron microscopy. Their dynamic mechanical properties and thermostability were measured by dynamic mechanical analysis (DMA) and thermogravimetric analysis. The results indicate that the thermotropic acetylene‐terminated liquid‐crystal monomer melted into a schlieren texture. MPBE and PSA could copolymerize to fix the mesogenic domain in the crosslinked network and form a homogeneous‐phase sea‐island structure, which improved the rigidity and toughness of the materials. DMA showed that the storage modulus of the PSA–MPBE resins increased by about 400 MPa compared to the those of the pure components. The SEM experiments showed a noticeable change in the morphology, from a typical brittle fracture for the pure PSA to microplastic deformation behavior for the PSA–MPBE resins. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45141.
Hydrophilic modification of a poly(ether sulfone) flat‐sheet ultrafiltration membrane applied to coking sewage
Authors: Ouyang Shu Guang , Yao Jun Yan , Zhu Guang Heng Wei , Liu Zhao Yue , Feng Chi , Wang Gang 
Published: April 2017

ABSTRACTIn this article, a new modified poly(ether sulfone) flat‐sheet ultrafiltration membrane, which is expected to effectively handle coking sewage, was prepared by an immersion precipitation phase‐inversion technique to settle the wastewater treatment problem in coking plants. Nanometer TiO2 particle–poly(ethylene glycol) (PEG) blends were used as additives to modify the membranes by a blending method. The effects of different PEG mass concentrations on the membrane structure and properties were studied. The pure water flux and chemical oxygen demand (COD) rejection rate were analyzed as aggregative indicators by the comprehensive evaluation method, and then, the optimal PEG mass concentration was determined. The results show that the best modified effect was obtained at a PEG mass concentration of 0.25%. When coking sewage in a secondary settling tank was filtered with such membranes, the COD rejection rate reached 90.68%, and the water flux was 127.21 L m−2 h−1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45149.
Survival Disparities Associated with Congenital Diaphragmatic Hernia
Authors: Hinton Cynthia F. , Siffel Csaba , Correa Adolfo , Shapira Stuart K. 
Published: April 2017

BackgroundWe assessed sociodemographic and clinical factors that are associated with survival among infants with congenital diaphragmatic hernia (CDH).MethodsUsing data from the Metropolitan Atlanta Congenital Defects Program, we ascertained 150 infants born with CDH between 1979 and 2003 and followed via linkage with state vital records and the National Death Index. Kaplan–Meier survival probabilities and adjusted hazard ratios (HRs) were calculated for socioeconomic and clinical characteristics.ResultsSurvival increased from 40 to 62% over the study period. White infants born before 1988 were 2.9 times less likely to survive than those born after 1988. Black infants' survival did not show significant improvement after 1988. White infants' survival was not significantly affected by poverty, whereas black infants born in higher levels of poverty were 2.7 times less likely to survive than black infants born in lower levels of neighborhood poverty. White infants with multiple major birth defects were 2.6 times less likely to survive than those with CDH alone. The presence of multiple defects was not significantly associated with survival among black infants.ConclusionsSurvival among infants and children with CDH has improved over time among whites, but not among blacks. Poverty is associated with lower survival among blacks, but not among whites. The presence of multiple defects is associated with lower survival among whites, but not among blacks. The differential effects of poverty and race should be taken into account when studying disparities in health outcomes. Birth Defects Research 109:816–823, 2017. © 2017 Wiley Periodicals, Inc.
Hydrogen sulfide attenuates homocysteine‐induced cognitive deficits and neurochemical alterations by improving endogenous hydrogen sulfide levels
Authors: Kumar Mohit , Modi Manish , Sandhir Rajat 
Published: April 2017

AbstractHyperomocysteinemia (HHcy) has been associated with mild cognitive impairment and dementia. Hydrogen sulfide (H2S) has been suggested to be an endogenous modulator of neuronal functions. However, the effect and mechanisms involved in beneficial effect of H2S has not been investigated in homocysteine (Hcy)‐induced cognitive deficits. This study has been designed to evaluate the effect of exogenous H2S on behavioral deficits and neurochemical alterations in HHcy animals. Hcy levels were significantly elevated in plasma, cortex, and hippocampus of Hcy administered animals. A progressive decline in memory functions and increased anxiolytic behavior was observed in HHcy animals. This was accompanied by decrease in endogenous H2S levels along with decreased activity of cystathionase (CSE) and cystathionine β‐synthase (CBS). However, a significant increase in CSE and CBS mRNAs was observed. In addition, the catecholamine and serotonin levels were reduced and the activity of monoamine oxidase A and B were increased in brain regions of HHcy animals. Haematoxylin and eosin staining revealed higher number of pyknotic cells in brain regions of HHcy animals. H2S administration was found to lower elevated plasma and brain Hcy levels. The activities of CBS, CSE, and levels of H2S were restored in HHcy animals administered H2S. Exogenous H2S also ameliorated behavioral deficits accompanied by significant increase in catecholamines. Histological analysis revealed normal cell morphology in Hcy‐treated animals supplemented with H2S. These results clearly demonstrate that the protective effect of H2S on Hcy‐induced cognitive deficits is mediated through increased catecholamine and H2S levels thereby suggesting its beneficial role in preventing HHcy‐induced neurodegeneration. © 2016 BioFactors, 43(3):434–450, 2017