bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral and crystallography studies of new palladacycle complexes with P,C‐ and C,C‐donor ligands; Application of (OAL16) to optimizing the yield of Mizoroki‐Heck reaction
Authors: Sabounchei Seyyed Javad , Badpa Khadijeh , Hashemi Ali , Moniriyan Faezeh , Gable Robert W. 
Published: March 2019

The new symmetrical diphosphonium salt [Ph2P(CH2)2PPh2(CH2C(O)C6H4Br)2] Br2 (S) was synthesized in the reaction of 1,2‐bis (diphenylphosphino) ethane (dppe) and related ketone. Further treatment with NEt3 gave the symmetrical α‐keto stabilized diphosphine ylide [Ph2P(CH2)2PPh2(CHC(O)C6H4Br)2] (Y1). The unsymmetrical α‐keto stabilized diphosphine ylide [Ph2P(CH2)2PPh2(CHC(O)C6H4Br)] (Y2) was synthesized in the reaction of diphosphine in 1:1 ratio with 2.3′‐dibromoacetophenone, then treatment with NEt3. The reaction of dibromo (1,5‐cyclooctadiene)palladium (II), [PdBr2(COD)] with this ligand (Y1) in equimolar ratio gave the new C,C‐chelated [PdBr2(Ph2P(CH2)2PPh2(C(H)C(O)C6H4Br)2)] (1) and with unsymmetrical phosphorus ylide [Ph2P(CH2)2PPh2C(H)C(O)C6H4Br] (Y2) gave the new P, C‐chelated palladacycle complex [PdBr2(Ph2P(CH2)2PPh2C(H)C(O)Br)] (2). These compounds were characterized successfully by FT‐IR, NMR (1H, 13C and 31P) spectroscopic methods and the crystal structure of Y1 and 2 were elucidated by single crystal X‐ray diffraction. The results indicated that the complex 1 was C, C‐chelated whereas complex 2 was P, C‐chelated. These air/moisture stable complexes were employed as efficient catalysts for the Mizoroki‐Heck cross‐coupling reaction of several aryl chlorides, and the Taguchi method was used to optimize the yield of Mizoroki‐Heck coupling. The optimum condition was found to be as followed: base; K2CO3, solvent; DMF and loading of catalyst; 0.005 mmol.
Perylene diimide‐modified magnetic γ‐Fe2O3/CeO2 nanoparticles as peroxidase mimics for highly sensitive colorimetric detection of Vitamin C
Authors: Lian Jiajia , Liu Pei , Li Xiaocai , Gao Linna , Luo Xiliang , Zhang Xiao , Shi Zhiqiang , Liu Qingyun 
Published: March 2019

Perylene diimide‐modified magnetic γ‐Fe2O3/CeO2 nanoparticles (γ‐Fe2O3/CeO2‐PDI) were prepared and exhibited excellent peroxidase‐like activity. The samples were characterized by HR‐TEM, XRD, Raman, N2 adsorption, magnetic strength and XPS. The obtained γ‐Fe2O3/CeO2‐PDI had size of 10~20 nm with high specific surface area of 77 m2/g, and could be easily separated from the aqueous solution by using a magnet, which are in favor of its practical application. Due to the decoration of PDI, the γ‐Fe2O3/CeO2‐PDI possessed more surface defects (Ce3+) and active oxygen species than that of γ‐Fe2O3/CeO2, resulting in the outstanding catalytic performance. And the composite catalyst also showed highly sensitive and selectivity toward VC with a limit of detection of 0.45 μM. Based on the fluorescent results, a possible hydroxyl radical (•OH) catalytic mechanism was proposed. It is believed that the as‐prepared γ‐Fe2O3/CeO2‐PDI nanoparticles are promising biosensors applied for biomedical and food analysis.
Plume dispersion behaviour and hazard identification for large quantities of liquid hydrogen leakage
Authors: Pu Liang , Shao Xiangyu , Zhang Shengqi , Lei Gang , Li Yanzhong 
Published: March 2019

AbstractHydrogen is a promising energy carrier. The primary issue of hydrogen utilisation is safety in various scenarios for the coming hydrogen economy. This study focuses on liquid hydrogen leakage, which is typically induced by structural failure in refuelling stations and transit vehicles. In the present study, the authors reveal the plume dispersion behaviour and the underlying mechanism from a macro perspective and identify the associated hazards in the whole dispersion history. These problems have drawn little attention in previous studies. A numerical investigation was conducted, and the flow‐field data were deeply investigated, which were insufficient in the previous experiment. The local turbulence and mixing induced by the temperature difference was revealed to be the major cause of hydrogen dispersion. The lift force induced by the density difference enhanced the dispersion. The dispersion behaviour was classified into three phases: the dense‐gas phase, rise phase, and passive phase. The rise phase is the major one for cryogenic hydrogen dispersion. The frostbite hazard can be ignored, owing to insufficient exposure duration. For wind velocities of 2.2, 5.0, and 10.0 m/s, the durations of the hazardous cloud are 56, 51, and 47 s, respectively. The maximum heights of the hazardous cloud are 23.6, 12.1, and 6.2 m, respectively. There is a high fire/explosion probability in the dense‐gas phase and a low probability in the latter two phases.
Structure evolution mechanism of polyacrylonitrile films incorporated with graphene oxide during oxidative stabilization
Authors: Li Fengmei , Chen Yankun , Li Mengzhu , Liu Yunfei , Wang Biao 
Published: March 2019

ABSTRACTOxidative stabilization is a key process for polyacrylonitrile (PAN)‐based carbon materials. During this process, oxygen has a significant influence on the formation of cyclization structure and crosslinking structure of PAN matrix. Here, graphene oxide (GO) was used as filler in PAN matrix, the structure evolution of GO/PAN composite was studied during oxidative stabilization. Solubility measurement revealed that the crosslinking degree increased, while the cyclization degree of stabilized films decreased after GO incorporation. The effect of GO on the structure of PAN film was characterized by XRD, DSC, DMA, FTIR, and XPS. These results verified that GO could initiate the cyclization reaction of PAN at a lower temperature. The carboxylic groups on GO sheets might take part in the cyclization reactions during the heat treatment. Moreover, the oxygen‐containing molecules released from GO decomposition during the heat treatment were beneficial to the formation of crosslinking structure. The possible mechanism of the structure evaluation was proposed in this article. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47701.
UHPLC–MS/MS analysis of sphingosine 1‐phosphate in joint cavity dialysate and hemodialysis solution of adjuvant arthritis rats: Application to geniposide pharmacodynamic study
Authors: Xuejing Dai , Wenyu Wang , Hong Wu , Zhengrong Zhang , Li Dai , Jun Fu , Ran Deng , Feng Li , Yan Wang , Xiang Zhan 
Published: March 2019

AbstractGeniposide (GE) is an iridoid glycoside compound with anti‐inflammatory effect. The potential of sphingosine 1‐phosphate (S1P) as a plasma marker in human diseases was suggested recently in the literature, which demonstrated that, in patients with inflammatory diseases, plasma S1P was elevated. It follows that the obstructive coronary artery disease can be predicted with serum S1P. Therefore, S1P can also be potentially used as a pharmacodynamic marker to study adjuvant arthritis (AA) rats. In the current study, a UHPLC–MS/MS method combined with the microdialysis sampling technique (using FTY720 phosphate as an internal standard) was adopted and validated to measure S1P levels in the hemodialysis fluid and joint cavity dialysates of AA rats after oral administration of GE. A S1P concentration–time curve in the dialysate was established in this study. It was demonstrated that GE exerted an anti‐inflammatory effect by reducing AA‐induced elevated S1P levels. It is showed that changes in S1P concentrations over time can be used to monitor the pharmacodynamic effects of GE in treating AA rats in pharmacodynamic studies.
Analyzing the use of adaptive learning in a flipped classroom for preclass learning
Authors: Kaw Autar , Clark Renee , Delgado Eleonora , Abate Nicholas 
Published: March 2019

AbstractPreclass learning, an obstacle in the success of a flipped classroom, is addressed via placing lessons on an online adaptive platform. The lessons combine the power of video lectures, textbook content, simulations, and assessments while using personalized paths for each student. This article describes the development of the adaptive lessons for a course in Numerical Methods, and the interpretation of the analytic data collected via the adaptive lesson platform and student focus groups over a two‐semester period with 146 students. Analytical data includes student metrics, such as the lesson scores and the time spent and lesson metrics, such as the percentage of students who completed the lesson and the percentage of possible adaptive paths used by students. The focus groups were conducted for two different demographic groups—students who are “white males” (comprise the majority of students in public engineering schools in the USA) and “other than white males”—to compare their perspectives on adaptive learning. Students in the focus group of the “other than white male” pupils demonstrated more favorable and positive perspectives towards the adaptive learning compared with the “white males”, although both groups identified benefits with the adaptive platform. Final examination scores were found to be correlated with the raw score of the adaptive lessons.
Isomers of Dithienocyclopentapyrene‐Based Non‐Fullerene Electron Acceptors: Configuration Effect on Photoelectronic Properties
Authors: Wu Jianglin , Chen Yao , Hu Bin , Pang Zhenguo , Lu Zhiyun , Huang Yan 
Published: March 2019

AbstractOne pair of isomers, centrosymmetric anti‐Py‐1 and axisymmetric syn‐Py‐2, was designed and synthesized with an acceptor–donor–acceptor (A–D–A) structure by choosing dithienocyclopentapyrene with four 4‐hexylphenyl side chains as the D unit, and 2‐(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐inden‐1‐ylidene) malononitrile as the A unit. In‐depth structure–property relationship studies revealed that the isomers have similar UV/Vis absorption, fluorescence emission, and energy levels but significant differences in molecular shape, polarity, and charge mobility. Solution‐processed bulk‐heterojunction (BHJ) small‐molecule organic solar cells with Py‐1 as the electron‐acceptor material and PTB7‐Th as the electron‐donor material exhibit a power conversion efficiency (PCE) of 6.07 %, or 60 % higher than that of Py‐2 (3.7 %), which could be mainly attributed to the higher and more balanced hole/electron mobilities and better phase separation of the Py‐1‐based active layer.
Analysis, modeling, and implementation of a new transformerless semi‐quadratic Buck–boost DC/DC converter
Authors: Hasanpour Sara , Mostaan Ali , Baghramian Alfred , Mojallali Hamed 
Published: March 2019

SummaryThis paper presents a novel transformerless semi‐quadratic buck‐boost converter (SQBuBoC). In the proposed SQBuBoC, two power switches with simultaneous operation are used and a higher step‐up/step‐down voltage conversion ratio is achieved compared with the traditional buck‐boost, Cuk, single‐ended primary‐inductor converter, and Zeta converters. The positive polarity of the output voltage, along with low ripple continuous input current and common ground between the source and the output voltages, are some features that make the suggested topology more suitable for many applications with wide range of output voltage such as photovoltaic systems. Moreover, the total voltage stress across the power switches in this converter is lower than the cascade boost, and the traditional buck‐boost converters led to power MOSFETs selection with lower drain‐source ON resistance (Rds) and efficiency improvement. All the steady‐state analysis and comparisons in continuous conduction mode (CCM) are discussed in details. In addition, to study the low frequency behavior of the SQBuBoC by means of the state‐space averaging technique, the small and large signal models of this converter in CCM are presented. Finally, the SQBuBoC analysis is justified using experimental results of a 50 W step‐up 25 V to 120 V and a 28 W step‐down 25 V to 14 V laboratory prototypes.
UHPLC–MS/MS quantitation of porphyroxine in opium and application of porphyroxine‐acetylated products as signature markers for heroin
Authors: Li Li , Panicker Sini , Casale Ellen M. 
Published: March 2019

AbstractPorphyroxine, a trace alkaloid in opium, was identified in the early 1800s and isolated/characterized in the 1960s. Recently, two significant porphyroxine‐related byproducts found in the acidic and neutral extracts of illicit heroin were characterized by this laboratory as the N‐acetyl‐O14‐desmethyl‐epi‐porphyroxine (B) and N,O8‐diacetyl‐O14‐desmethyl‐epi‐porphyroxine (C). The prevalence of the B and C compounds has been consistent in the following order of abundance for the thousands of authentic heroin samples analyzed: Southwest Asia (SWA) > South America (SA) > Southeast Asia (SEA) > Mexico (MEX). In this research, a rapid and efficient ultra‐high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method was developed to determine the content of porphyroxine and five primary alkaloids (morphine, codeine, thebaine, noscapine, and papaverine) in opium after extraction with methanol/water (50/50). The method was validated in terms of linearity, accuracy, recovery, and precision for porphyroxine. The limit of quantitation (LOQ) for porphyroxine was 2.5 ng/mL. The developed method was successfully applied to a total of 114 authentic opium samples from the major poppy‐growing regions. The amount of porphyroxine was determined at the level of part per thousand (‰) and the relative concentrations to morphine were in the range of 1x10−4 and 1x10−2 with an order of SWA > SEA, SA > MEX for its average abundance, which is consistent with the order of the average abundance of its acetylated products (B, C) in illicit heroin. This study reveals the significance of porphyroxine and its acylated compounds in classifying heroin and opium samples to major geographical regions of production.
Genomic, ecological, and morphological approaches to investigating species limits: A case study in modern taxonomy from Tropical Eastern Pacific surgeonfishes
Authors: Ludt William B. , Bernal Moisés A. , Kenworthy Erica , Salas Eva , Chakrabarty Prosanta 
Published: March 2019

AbstractA wide variety of species are distinguished by slight color variations. However, molecular analyses have repeatedly demonstrated that coloration does not always correspond to distinct evolutionary histories between closely related groups, suggesting that this trait is labile and can be misleading for species identification. In the present study, we analyze the evolutionary history of sister species of Prionurus surgeonfishes in the Tropical Eastern Pacific (TEP), which are distinguished by the presence or absence of dark spots on their body. We examined the species limits in this system using comparative specimen‐based approaches, a mitochondrial gene (COI), more than 800 nuclear loci (Ultraconserved Elements), and abiotic niche comparisons. The results indicate there is a complete overlap of meristic counts and morphometric measurements between the two species. Further, we detected multiple individuals with intermediate spotting patterns suggesting that coloration is not diagnostic. Mitochondrial data recovered a single main haplotype shared between the species and all locations resulting in a complete lack of structure (ΦST = 0). Genomic analyses also suggest low levels of genetic differentiation (FST = 0.013), and no alternatively fixed SNPs were detected between the two phenotypes. Furthermore, niche comparisons could not reject niche equivalency or similarity between the species. These results suggest that these two phenotypes are conspecific and widely distributed in the TEP. Here, we recognize Prionurus punctatus Gill 1862 as a junior subjective synonym of P. laticlavius (Valenciennes 1846). The underlying causes of phenotypic variation in this species are unknown. However, this system gives insight into general evolutionary dynamics within the TEP.
A palaeomagnetic study of the Middle Permian and Middle Triassic limestones from Shan State, Myanmar: Implications for collision of the Sibumasu Terrane and Indochina Terrane
Authors: Zhao Jie , Huang Baochun , Yan Yonggang , Bai Qianhui , Dong Yunpeng , Win Zaw , Aung Hla Hla , Yang Xiaodong 
Published: March 2019

We report herein a new palaeomagnetic study on the Middle Permian and Middle Triassic limestones from Shan State of eastern Myanmar, aiming to resolve the spatial location of the Sibumasu Terrane during the collision of tectonic blocks in Southeast Asia and to constrain the timing of convergence between the Sibumasu Terrane and Indochina Terrane. Based on the rock magnetic and palaeomagnetic experiments, three stable characteristic remnant magnetizations are recognized from limestone specimens of Middle Permian and Middle Triassic age. The characteristic Component C of the Middle Permian limestone passed the fold test at 95% confidence level, indicative of a pre‐folding origin. The mean direction of this component is D = 10.7°, I = 17.9° (κ = 130.3, α95 = 10.8°) before and D = 13.7°, I = −25.3° (κ = 1894.9, α95 = 2.8°) after tilt correction, corresponding to a palaeomagnetic pole at 254.1°E, 53.2°N (A95 = 1.7°). This suggests that the Sibumasu Terrane was placed at a palaeolatitude of ~13.0°S during the Middle Permian. The Component C separated from the Middle Triassic samples also passed the fold test with a mean direction of D = 207.3°, I = −8.3° (κ = 12.9, α95 = 6.2°) before tilt correction and D = 205.6°, I = −33.5° (κ = 27.1, α95 = 4.2°) after tilt correction, corresponding to a palaeomagnetic pole at 187.3°E, 65.8°N (dp/dm = 2.7°/4.8°). This implies that the Sibumasu Terrane was located at a palaeolatitude of ~18.3°N during the Middle Triassic. Based upon the detailed palaeomagnetic analysis, this study supports the view that the collision of the Sibumasu Terrane and Indochina Terrance occurred during or before the Middle–Late Triassic times.
Integral Learning and Working: Becoming a Learning Organization
Authors: Holba Annette M. , Bahr Patricia T. , Birx Donald L. , Fischler Mark J. 
Published: March 2019

AbstractIntegration as a methodology for redesigning higher education is the main theme of this chapter. After defining how the authors understand and envision integration as an organizational model and as a learning model, they maintain that setting the expectation of the importance of becoming a learning organization is essential for successful whole system change.
Biogeochemistry of dissolved carbon, major, and trace elements during spring flood periods on the Ob River
Authors: Vorobyev Sergey N. , Pokrovsky Oleg S. , Kolesnichenko Larisa G. , Manasypov Rinat M. , Shirokova Liudmila S. , Karlsson Jan , Kirpotin Sergey N. 
Published: March 2019

AbstractDetailed knowledge of the flood period of Arctic rivers remains one of the few factors impeding rigorous prediction of the effect of climate change on carbon and related element fluxes from the land to the Arctic Ocean. In order to test the temporal and spatial variability of element concentration in the Ob River (western Siberia) water during flood period and to quantify the contribution of spring flood period to the annual element export, we sampled the main channel year round in 2014–2017 for dissolved C, major, and trace element concentrations. We revealed high stability (approximately ≤10% relative variation) of dissolved C, major, and trace element concentrations in the Ob River during spring flood period over a 1‐km section of the river channel and over 3 days continuous monitoring (3‐hr frequency). We identified two groups of elements with contrasting relationship to discharge: (a) DIC and soluble elements (Cl, SO4, Li, B, Na, Mg, Ca, P, V, Cr, Mn, As, Rb, Sr, Mo, Ba, W, and U) negatively correlated (p < 0.05) with discharge and exhibited minimal concentrations during spring flood and autumn high flow and (b) DOC and particle‐reactive elements (Al, Fe, Ti, Y, Zr, Nb, Cs, REEs, Hf, Tl, Pb, and Th), some nutrients (K), and metalloids (Ge, Sb, and Te), positively correlated (p < 0.05) with discharge and showed the highest concentrations during spring flood. We attribute the decreased concentration of soluble elements with discharge to dilution by groundwater feeding and increased concentration of DOC and particle‐reactive metals with discharge to leaching from surface soil, plant litter, and suspended particles. Overall, the present study provides first‐order assessment of fluxes of major and trace elements in the middle course of the Ob River, reveals their high temporal and spatial stability, and characterizes the mechanism of river water chemical composition acquisition.
Long‐term assessment of nutrient flow pathway dynamics and in‐stream fate in a temperate karst agroecosystem watershed
Authors: Ford William I. , Husic Admin , Fogle Alex , Taraba Joseph 
Published: March 2019

AbstractNutrient dynamics in karst agroecosystems remain poorly understood, in part due to limited long‐term nested datasets that can discriminate upland and in‐stream processes. We present a 10‐year dataset from a karst watershed in the Inner‐Bluegrass Region of central Kentucky, consisting of nitrate (nitrate‐N [NO3−]), dissolved reactive phosphorus (DRP), total organic carbon (TOC), and total ammoniacal‐N (TAN) measurements at nested spring and stream sites as well as flowrate at the watershed outlet. Hydrograph separation techniques were coupled with multiple linear regression and Empirical Mode Decomposition time‐series analysis to determine significance of seasonal processes and to generate continuous estimates of nutrient pathway loadings. Further, we used model results of benthic algae growth and decomposition dynamics from a nearby watershed to assess if transient storage in algal biomass could explain differences in spring and downstream watershed nutrient loading. Results highlight statistically significant seasonality for all nutrients at stream sites, but only for NO3− at springs with longitudinal variability showing significant decreases occurring from spring to stream sites for NO3− and DRP, and significant increases for TOC and TAN. Pathway loading analysis highlighted the importance of slow flow pathways to source approximately 70% of DRP and 80% of NO3−. Results for in‐stream dynamics suggest that benthic autotroph dynamics can explain summer deviations for TOC, TAN, and DRP but not NO3−. Regarding upland dynamics, our findings agree well with existing perceptions in karst for N pathways and upland source seasonality but deviate from perceptions that karst conduits are retentive of P, reflecting the limited buffering capacity of the soil profile and conduit sediments in the Inner‐Bluegrass. Regarding in‐stream fate, our findings highlighted the significance of seasonally driven nutrient processing in the bedrock‐controlled streambed to influence nutrient fluxes at the watershed outlet. Contrary to existing perceptions, we found high N attenuation and an unexplained NO3− sink in the bedrock stream, leading us to postulate that floating macrophytes facilitate high rates of denitrification.