bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of multiphase fluid imbibition in shale through synchrotron‐based dynamic micro‐CT imaging
Authors: Peng Sheng , Xiao Xianghui 
Published: June 2017

AbstractWhile substantial advances were made in pore system characterization in shale in the past decade, understanding of fundamentals of multiphase fluid flow in shale remains limited. The complexity of multiphase fluid flow in shale is related to many factors including nanoscale to submicron‐scale pore systems, differences in mineralogy and associated surface wettability, heterogeneity of these properties at different scales, and possible existence of microfractures. Previous work related to fluid flow, such as permeability measurement, spontaneous imbibition, and wettability analysis, includes many simplified assumptions/hypotheses with limited consideration of small‐scale details. In addition, these studies were mostly focused on single‐phase phenomena. Direct observation of multiphase fluid flow in shale showing small‐scale details is highly desired. In this study, dynamic imaging using synchrotron‐based micro‐CT (computed microtomography) was conducted on two shale samples to investigate multiphase (oil and water) spontaneous imbibition. The results revealed many details of multiphase flow in shale, including pore connectivity, porosity and permeability layered distribution, and wettability of microfractures and pores. At the same time, results illustrate the complexity of multiphase flow in shale and gaps in understanding that need further investigation.
A cautionary tale: A study of a methane enhancement over the North Sea
Authors: Cain M. , Warwick N. J. , Fisher R. E. , Lowry D. , Lanoisellé M. , Nisbet E. G. , France J. , Pitt J. , O'Shea S. , Bower K. N. , Allen G. , Illingworth S. , Manning A. J. , Bauguitte S. , Pisso I. , Pyle J. A. 
Published: June 2017

AbstractAirborne measurements of a methane (CH4) plume over the North Sea from August 2013 are analyzed. The plume was only observed downwind of circumnavigated gas fields, and three methods are used to determine its source. First, a mass balance calculation assuming a gas field source gives a CH4 emission rate between 2.5 ± 0.8×104 and 4.6 ± 1.5×104 kg h−1. This would be greater than the industry's reported 0.5% leak rate if it were emitting for more than half the time. Second, annual average UK CH4 emissions are combined with an atmospheric dispersion model to create pseudo‐observations. Clean air from the North Atlantic passed over mainland UK, picking up anthropogenic emissions. To best explain the observed plume using pseudo‐observations, an additional North Sea source from the gas rigs area is added. Third, the δ13C‐CH4 from the plume is shown to be −53‰, which is lighter than fossil gas but heavier than the UK average emission. We conclude that either an additional small‐area mainland source is needed, combined with temporal variability in emission or transport in small‐scale meteorological features. Alternatively, a combination of additional sources that are at least 75% from the mainland (−58‰) and up to 25% from the North Sea gas rigs area (−32‰) would explain the measurements. Had the isotopic analysis not been performed, the likely conclusion would have been of a gas field source of CH4. This demonstrates the limitation of analyzing mole fractions alone, as the simplest explanation is rejected based on analysis of isotopic data.
Influence of stratospheric air masses on radiotracers and ozone over the central Mediterranean
Authors: Brattich E. , Orza J. A. G. , Cristofanelli P. , Bonasoni P. , Tositti L. 
Published: June 2017

AbstractThis work aims at determining the characteristics and the preferred source regions of stratospheric air masses at the Mt. Cimone World Meteorological Organization‐Global Atmosphere Watch station located in the Italian northern Apennines (44°11′N, 10°42′E, 2165 m above sea level) , a site which is considered representative of Southern Europe‐Mediterranean free troposphere. Source regions of high concentrations of 7Be, 7Be/210Pb, and O3 and regions originating high potential vorticity values are analyzed by means of trajectory statistical methods applied over the time series collected in the period of 1998–2011 to this aim. Our analysis points out the frequent occurrence of stratosphere‐to‐troposphere exchange in the North America and northern Atlantic region, which can be linked to the usual location of the polar‐front and subtropical jet streams in these two regions, but also to the tropopause discontinuity and to the high cyclogenetic activity in the Atlantic region. High 7Be concentrations associated with trajectories of high‐latitude origin descend from high altitudes to the study site, while at midlatitudes trajectories arrive from relatively lower levels. The geographical distribution of the tropopause crossing of air masses before arriving the study site points out particularly to Greenland. Our results also suggest the importance of the interaction between upper level disturbances and the Alps mountain range as a driver for stratosphere‐to‐troposphere exchange. In this case, the time between the tropopause crossing and the arrival at the elevated study site is less than 24 h and frequently below 6 h. The Atlas range in northern Africa plays a similar role though with lower influence.
Relationships between total lightning, deep convection, and tropical cyclone intensity change
Authors: Xu Weixin , Rutledge Steven A. , Zhang Wenjuan 
Published: June 2017

AbstractThis study investigates the characteristics of total lightning in the inner core (INCO, 0–100 km) and outer rainband (OB, 200–400 km) of tropical cyclones (TC). Relationships between flash density (FLD), convective intensity, and TC intensity change are further examined. FLD shows a bimodal structure with a strong maximum in the eyewall (INCO, 0–50 km) and a secondary maximum in the OB. FLD maximizes under conditions of warmest sea surface temperature (SST) and large values of vertical wind shear. Compared to OB FLD, INCO FLD is less sensitive to SST increase but shows greater variability in relation to shear. Intensifying TCs have substantially lower INCO (but higher OB) FLD compared to weakening and neutral TCs. Similar trends are shown in radar quantities (volume of 30 dBZ echoes in the mixed phase). rapidly intensifying (RI) TCs also show significantly smaller FLD and VOL30 than slowly intensifying TCs, indicating the potential of these parameters in forecasting RI. INCO (OB) FLD decreases (increases) 12–18 h preceding the onset of RI, while INCO (OB) FLD increases (decreases) 6–12 h prior to TC weakening. These relationships between lightning and TC intensity change (+24 h) are generally maintained regardless of prior (−24 h) TC intensity change status. However, convective depth and vertically integrated ice content in the INCO increased preceding TC intensification, suggesting the lack of supercooled liquid content and establishment of glaciated conditions (evident by an increase in the 20 dBZ and decrease in the 30 dBZ echo volume) in the INCO of intensifying TCs, especially RI.
On the far‐zone electromagnetic field of a vertical Hertzian dipole over an imperfectly conducting half‐space with extensions to plasmonics
Authors: Michalski Krzysztof A. , Lin Hung‐I 
Published: June 2017

AbstractNew asymptotic formulas for the electromagnetic fields of a vertical Hertzian dipole over an imperfectly conducting half‐space are derived using two variants of the modified saddle point method, referred to as subtractive and multiplicative. The accuracy of the two far‐zone formulations is assessed by comparisons with the state‐of‐the‐art Norton‐Bannister theory and with the rigorous results of numerical integration for problems involving seawater in the microwave range and gold in the visible range. It is found that the performance of the three approximate methods is similar, except at the surface of plasmonic media, where the saddle point methods are superior to the Norton‐Bannister formulation.
Synergistic Strategies of Cyano Migration and Photocatalysis for Difunctionalization of Unactivated Alkenes: Synthesis of Di‐ and Mono‐Fluorinated Alkyl Nitriles
Authors: Ren Rongguo , Wu Zhen , Huan Leitao , Zhu Chen 
Published: June 2017

AbstractA general protocol for the challenging cyanofluoroalkylation of unactivated alkenes is disclosed. A broad range of synthetically useful di‐ and mono‐fluorinated alkyl nitriles are readily obtained in good yields under mild reaction conditions. The efficient combination of intramolecular cyano migration and photoredox catalysis significantly expands the field of difunctionalization of olefins.magnified image
Highly Enantioselective Synthesis of 11‐Substituted 10,11‐Dihydrodibenzo[b,f][1,4]thiazepines through a Proline‐Catalyzed Mannich Reaction of Seven‐Membered Cyclic Imines with Ketones
Authors: Deng Zhuo‐Fei , Huang Bo , Xu Huajing , Shi Feng , Wang You‐Qing 
Published: June 2017

AbstractHighly enantioselective Mannich addition reactions of N,S‐heterocyclic dibenzo[b,f][1,4]thiazepines as seven‐membered cyclic imine substrates with ketones were developed by using proline as an organocatalyst. Substituted dibenzo[b,f][1,4]thiazepines and various unsymmetrical alkyl methyl ketones were used as substrates and optimized reaction conditions offered an efficient method to synthesize optically active 11‐substituted 10,11‐dihydrodibenzo[b,f][1,4]thiazepine derivatives that contained a carbonyl functional group in 91–99 % ee. Furthermore, we found that the reactions could also be performed on a gram scale, whilst maintaining high yields and enantioselectivities. The carbonyl group of the Mannich products also underwent diastereoselective reduction, thus yielding a new hydroxy‐substituted chiral stereogenic center with moderate‐to‐excellent diastereoselectivities, good yields, and without the loss of enantiomeric excess.
Probing the Role of a Non‐Thermal Plasma (NTP) in the Hybrid NTP Catalytic Oxidation of Methane
Authors: Gibson Emma K , Stere Cristina E , Curran‐McAteer Bronagh , Jones Wilm , Cibin Giannantonio , Gianolio Diego , Goguet Alexandre , Wells Peter P. , Catlow C. Richard A. , Collier Paul , Hinde Peter , Hardacre Christopher 
Published: June 2017

AbstractThree recurring hypotheses are often used to explain the effect of non‐thermal plasmas (NTPs) on NTP catalytic hybrid reactions; namely, modification or heating of the catalyst or creation of new reaction pathways by plasma‐produced species. NTP‐assisted methane (CH4) oxidation over Pd/Al2O3 was investigated by direct monitoring of the X‐ray absorption fine structure of the catalyst, coupled with end‐of‐pipe mass spectrometry. This in situ study revealed that the catalyst did not undergo any significant structural changes under NTP conditions. However, the NTP did lead to an increase in the temperature of the Pd nanoparticles; although this temperature rise was insufficient to activate the thermal CH4 oxidation reaction. The contribution of a lower activation barrier alternative reaction pathway involving the formation of CH3(g) from electron impact reactions is proposed.
Quantification of β‐eudesmol in rat plasma using LC–MS/MS and its application to a pharmacokinetic study
Authors: Jiang Ligang , Zhang Chunyang , Li Haiping 
Published: June 2017

AbstractA sensitive and specific LC–MS/MS assay for determination of β‐eudesmol in rat plasma was developed and validated. After liquid–liquid extraction with ethyl ether, the analyte and IS were separated on a Capcell Pak C18 column (50 × 2.0 mm, 5 μm) by isocratic elution with acetonitrile—water–formic acid (77.5:22.5:0.1, v/v/v) as the mobile phase at a flow rate of 0.4 mL/min. An ESI source was applied and operated in positive ion mode; a selected reaction monitoring scan was used for quantification by monitoring the precursor–product ion transitions of m/z 245.1 → 163.1 for β‐eudesmol and m/z 273.4 → 81.2 for IS. Good linearity was observed in the concentration range of 3–900 ng/mL for β‐eudesmol in rat plasma. Intra‐ and inter‐day precision and accuracy were both within ±14.3%. This method was applied for pharmacokinetic studies after intravenous bolus of 2.0 mg/kg or intragastric administration of 50 mg/kg β‐eudesmol in rats.
Development of a HPLC method for determination of four UV filters in sunscreen and its application to skin penetration studies
Authors: Souza Carla , Maia Campos Patrícia M.B.G. 
Published: June 2017

AbstractThis study describes the development, validation and application of a high‐performance liquid chromatography (HPLC) method for the simultaneous determination of the in vitro skin penetration profile of four UV filters on porcine skin. Experiments were carried out on a gel‐cream formulation containing the following UV filters: diethylamino hydroxybenzoyl hexyl benzoate (DHHB), bis‐ethylhexyloxyphenol methoxyphenyl triazine (BEMT), methylene bis‐benzotriazolyl tetramethylbutylphenol (MBBT) and ethylhexyl triazone (EHT). The HPLC method demonstrated suitable selectivity, linearity (10.0–50.0 μg/mL), precision, accuracy and recovery from porcine skin and sunscreen formulation. The in vitro skin penetration profile was evaluated using Franz vertical diffusion cells for 24 h after application on porcine ear skin. None of the UV filters penetrated the porcine skin. Most of them stayed on the skin surface (>90%) and only BEMT, EHT and DHHB reached the dermis plus epidermis layer. These results are in agreement with previous results in the literature. Therefore, the analytical method was useful to evaluate the in vitro skin penetration of the UV filters and may help the development of safer and effective sunscreen products.
A validated UHPLC–MS/MS method for the measurement of riluzole in plasma and myocardial tissue samples
Authors: Parker Suzanne L. , Guerra Valero Yarmarly C. , Lipman Jeffrey , Weiss Steven , Smith Camilla , Russell Lyndal , Smith Paul , Roberts Jason A. , Wallis Steven C. 
Published: June 2017

AbstractThrough blocking the cardiac persistent sodium current, riluzole has the potential to prevent myocardial damage post cardiac bypass surgery. A sensitive UHPLC–MS/MS method was developed and validated for quantitation of riluzole and 5‐methoxypsoralen in human plasma and myocardial tissue homogenate using a liquid–liquid extraction with dichloromethane. The chromatographic separation was achieved using Shimadzu Shim‐pack XR‐ODS III, 2.0 × 50 mm, 1.6 μm column with a gradient mobile phase comprising methanol and ammonium acetate buffer pH 3.6 in purified water. The analyte and internal standard were separated within 3.5 min. Riluzole quantitation was achieved using the mass transitions of 235–138 for riluzole and 217–156 for 5‐methoxypsoralen. The method was linear for riluzole plasma concentrations from 0.2 to 500 ng/mL and myocardial tissue homogenate concentrations from 0.2 to 100 ng/mL. The method developed was successfully applied to a clinical study for patients receiving riluzole while undergoing cardiac bypass surgery.
A highly sensitive LC–MS/MS method for simultaneous determination of glycyrrhizin and its active metabolite glycyrrhetinic acid: Application to a human pharmacokinetic study after oral administration
Authors: Suzuki Tsuneharu , Tsukahara Michiko , Akasaka Yuko , Inoue Hideo 
Published: June 2017

AbstractA highly sensitive liquid chromatography tandem mass spectrometry (LC–MS/MS) method for simultaneous determination of glycyrrhizin (GL) and its active metabolite, glycyrrhetinic acid (GA), from human plasma was validated and applied to a human pharmacokinetic study. The analytes were extracted from human plasma using an Oasis MAX cartridge and chromatographic separation was performed on an Inertsil ODS‐3 column. The detection was performed using an API 4000 mass spectrometer operating in the positive electrospray ionization mode. Selected ion monitoring transitions of m/z 823 → 453 for GL and m/z 471 → 149 for GA were obtained. The response was a linear function of concentration over the ranges of 0.5–200 ng/mL for GL and 2–800 ng/mL for GA (both R2 > 0.998). Using this method, the pharmacokinetics of GL after single oral administration of a clinical dose (75 mg) to six healthy male Japanese volunteers were evaluated. GL was detected in the plasma of all subjects and the average peak concentration was 24.8 ± 12.0 ng/mL. In contrast, peak concentration of GA was 200.3 ± 60.3 ng/mL, i.e. ~8‐fold higher than that of GL. This is the first report clarifying pharmacokinetic profiles of GL and GA simultaneously at a therapeutic oral dose of a GL preparation.
LC–MS/MS characterization, anti‐inflammatory effects and antioxidant activities of polyphenols from different tissues of Korean Petasites japonicus (Meowi)
Authors: Choi Jin Young , Desta Kebede Taye , Saralamma Venu Venkatarame Gowda , Lee Sung Joong , Lee Soo Jung , Kim Seong Min , Paramanantham Anjugam , Lee Ho Jeong , Kim Yun‐Hi , Shin Ho‐Chul , Shim Jae‐Han , Warda Mohamad , Hacımüftüoğlu Ahmet , Jeong Ji Hoon , Shin Sung Chul , Kim Gon‐Sup , Abd El‐Aty A. M. 
Published: June 2017

AbstractThe Korean Petasites japonicus is a perennial plant used in folk medicine as a remedy for many diseases and popularly consumed as spring greens. Ten polyphenols were characterized from the leaves, stems and roots of this plant via high‐performance liquid chromatography–tandem mass spectrometry. Individual polyphenols were quantified for the first time using calibration curves of six structurally related external standards. Validation data indicated that coefficients of determinations (R2) were ≥0.9702 for all standards. Recoveries measured at 50 and 100 mg/L were 80.0–91.9 and 80.3–105.3%, respectively. Precisions at these two concentration levels were 0.7–6.1 and 1.1–5.5%, respectively. The total number of identified components was largest for the leaves and smallest for the stems. The leaf and root polyphenolic extracts showed anti‐inflammatory effects by inducing LPS‐activated COX‐2 and iNOS protein levels in mouse macrophage RAW 264.7 cells. The antioxidant capacity of the polyphenols, when evaluated for DPPH (α,α‐diphenyl‐β‐picrylhydrazyl)ˑ, ABTS+ [2–2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid)] and superoxide radical scavenging activities, and in ferric reducing ability of plasma (FRAP) assays, was highest in the leaf and lowest in the stem. This trend suggests that the antioxidant capacities depend primarily on polyphenol concentration in each tissue. The current findings suggest that polyphenols derived from P. japonicas tissues could have potential as functional health foods.
Lansoprazole‐sulfide, pharmacokinetics of this promising anti‐tuberculous agent
Authors: Mdanda Sipho , Baijnath Sooraj , Shobo Adeola , Singh Sanil D. , Maguire Glenn E.M. , Kruger Hendrik G. , Arvidsson Per I. , Naicker Tricia , Govender Thavendran 
Published: June 2017

AbstractLansoprazole (LPZ) is a commercially available proton‐pump inhibitor whose primary metabolite, lansoprazole sulfide (LPZS) was recently reported to have in vitro and in vivo activity against Mycobacterium tuberculosis. It was also reported that a 300 mg kg−1 oral administration of LPZS was necessary to reach therapeutic levels in the lung, with the equivalent human dose being unrealistic. A validated liquid chromatography–tandem mass spectrometric method (LC–MS/MS) for the simultaneous quantification LPZ and LPZS in rat plasma and lung homogenates was developed. We administered 15 mg kg−1 oral doses of LPZ to a healthy rat model to determine the pharmacokinetics of its active metabolite, LPZS, in plasma and lung tissue. We found that the LPZS was present in amounts that were below the limit of quantification. This prompted us to administer the same dose of LPZS to the experimental animals intraperitoneally (i.p.). Using this approach, we found high concentrations of LPZS in plasma and lung, 7841.1 and 9761.2 ng mL−1, respectively, which were significantly greater than the minimum inhibitory concentration (MIC) for Mycobacterium tuberculosis. While oral and i.p. administration of LPZ resulted in significant concentrations in the lung, it did not undergo sufficient cellular conversion to its anti‐TB metabolite. However, when LPZS itself was administered i.p., significant amounts penetrated the tissue. These results have implications for future in vivo studies exploring the potential of LPZS as an anti‐TB compound.
Exploration of Spinel LiCrTiO4 as Cathode Material for Rechargeable Mg‐Li Hybrid Batteries
Authors: Yao Ye , Zhang Lu , Bie Xiaofei , Chen Hong , Wang Chunzhong , Du Fei , Chen Gang 
Published: June 2017

AbstractMg‐Li hybrid batteries have attracted wide interest in recent years because of their potential safety as well as their cost benefit and high volumetric capacity. However, slow kinetic properties strongly hinder their commercial application. In this study, we have prepared spinel LiCrTiO4 by a solid‐state reaction and have conducted a comprehensive study aimed at improving the performance of Mg‐Li hybrid batteries by optimizing the dual‐salt electrolyte. LiCrTiO4 has been found to show reversible discharge/charge capacities of 178 and 169 mA h g−1 in electrolytes of 1 m LiCl and 0.3 m APC (all‐phenyl‐complex), respectively. When the concentration of APC was increased to 0.4 m, LiCrTiO4 showed a high capacity retention of 95 % after 30 cycles. In addition, no phase transition could be observed for an LiCrTiO4 electrode in a dual‐salt system, suggesting high electrochemical reversibility. Ex situ EDX and SEM studies have indicated that only Li+ ions are inserted into the cathode side, while Mg2+ ions are reversibly deposited on the surface of Mg metal without dendrite‐like growth, indicative of good safety of the Mg‐Li hybrid batteries.
Stimuli‐Responsive Metal–Organic Framework (MOF) with Chemo‐Switchable Properties for Colorimetric Detection of CHCl3
Authors: Razavi Sayed Ali Akbar , Masoomi Mohammad Yaser , Morsali Ali 
Published: June 2017

AbstractThe ligands 3,6‐di(pyridin‐4‐yl)‐1,4‐dihydro‐1,2,4,5‐tetrazine (H2DPT), as a pillar spacer, and 4,4′‐oxybis(benzoic acid) (H2OBA), as a dicarboxylate linker, have been used to develop a dihydrotetrazine‐functionalized pillared metal–organic framework (MOF), [Zn(OBA)(H2DPT)0.5]⋅DMF (TMU‐34), as a functionally convertible stimuli‐responsive MOF‐based sensor. Sonochemically synthesized TMU‐34 powder has been employed in the sensing of volatile organic compounds (VOCs). The results show that TMU‐34 can act as a solid‐state, naked‐eye visual chemosensor for the detection of chloroform in the liquid and gas phases. TMU‐34, as a chemo‐switchable MOF with rapid response, undergoes a significant color change from yellow to pink through reversible dynamic conversion of dihydrotetrazine into tetrazine upon exposure to chloroform in the presence of other VOCs. Whereas other colorimetric MOF‐based sensors show a wide range of color changes in the presence of different analytes, TMU‐34 undergoes a color change only in the presence of chloroform. A mechanism for the observed color change is proposed on the basis of UV/Vis and 1H NMR spectroscopic studies. These observations reveal that TMU‐34 represents one of the most promising candidates for the highly selective and sensitive detection of chloroform.
Direct C2‐Functionalization of Indoles Triggered by the Generation of Iminium Species from Indole and Sulfonium Salt
Authors: Tayu Masanori , Nomura Kazuya , Kawachi Koki , Higuchi Kazuhiro , Saito Nozomi , Kawasaki Tomomi 
Published: June 2017

AbstractAn indole core bearing a functional group on the C2 position is often found as a key structure in biologically active natural products and pharmaceuticals. Here, we report direct C2‐functionalization of indoles triggered by the formation of an iminium species generated from indole and a sulfonium reagent. The reaction proceeded under very mild conditions to give the corresponding C2‐substituted indole derivatives in good to high yields.