bluuebunny/crossref_metadata_2025_split huggingface dataset:
Friedel‐Crafts dealkylation reaction mediated by a stereoselective proton transfer in the fragmentation of protonated cyclic indolyl α‐amino esters
Authors: Cao Xiaoji , Wang Ye , Mo Yawen , Wu Liang , Mo Weimin 
Published: June 2016

RationaleChiral cyclic indolyl α‐amino esters are valuable substructures of peptides and peptidomimetics. Systematically exploring the fragmentation behavior of the protonated cyclic indolyl α‐amino esters by a combination of high‐resolution high‐energy collisional dissociation mass spectrometry, hydrogen‐deuterium exchange experiments and density functional theory (DFT) calculations is useful for further understanding their intrinsic properties and the fragmentation mechanisms of peptidomimetics constructed with them.MethodsAll high‐resolution high‐energy collisional dissociation tandem mass spectrometry experiments were carried out using electrospray ionization hybrid Quadrupole‐Orbitrap mass spectrometry in positive ion mode. Only the labile hydrogens were exchanged with deuterium in hydrogen‐deuterium exchange experiments. Theoretical calculations were carried out by the DFT method at the B3LYP level with the 6‐311G(d,p) basis set in the Gaussian 03 package of programs.ResultsIn the fragmentation of protonated cyclic indolyl α‐amino esters, when the two labile hydrogens on the N8 position are successively transferred to the C3 and C4 positions, a Friedel‐Crafts dealkylation reaction takes place spontaneously, with concomitant formation of an ion‐neutral complex of [cyclic N‐sulfonyl ketimino esters/protonated indoles]. Direct separation of this complex formed the protonated indoles, while a stereoselective proton transfer between the two components in the complex gave rise to protonated cyclic N‐sulfonyl ketimino esters, which coincided with the hydrogen‐deuterium experiments.ConclusionsUsing H/D exchange experiments combined with theoretical calculations, a Friedel‐Crafts dealkylation reaction mediated by a stereoselective proton transfer in the [cyclic N‐sulfonyl ketimino esters/protonated indoles] complex was proposed for the fragmentation of protonated cyclic indolyl α‐amino esters in high‐energy collisional dissociation tandem mass spectrometry for the first time. Copyright © 2016 John Wiley & Sons, Ltd.
Identification of allocryptopine and protopine metabolites in rat liver S9 by high‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry
Authors: Huang Ya‐Jun , Xiao Sa , Sun Zhi‐Liang , Zeng Jian‐Guo , Liu Yi‐Song , Liu Zhao‐Ying 
Published: June 2016

RationaleAllocryptopine (AL) and protopine (PR) have been extensively studied because of their anti‐parasitic, anti‐arrhythmic, anti‐thrombotic, anti‐inflammatory and anti‐bacterial activity. However, limited information on the pharmacokinetics and metabolism of AL and PR has been reported. Therefore, the purpose of the present study was to investigate the in vitro metabolism of AL and PR in rat liver S9 using a rapid and accurate high‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry (HPLC/QqTOFMS) method.MethodsThe incubation mixture was processed with 15% trichloroacetic acid (TCA). Multiple scans of AL and PR metabolites and accurate mass measurements were automatically performed simultaneously through data‐dependent acquisition in only a 30‐min analysis. The structural elucidations of these metabolites were performed by comparing their changes in accurate molecular masses and product ions with those of the precursor ion or metabolite.ResultsEight and five metabolites of AL and PR were identified in rat liver S9, respectively. Among these metabolites, seven and two metabolites of AL and PR were identified in the first time, respectively. The demethylenation of the 2,3‐methylenedioxy, the demethylation of the 9,10‐vicinal methoxyl group and the 2,3‐methylenedioxy group were the main metabolic pathways of AL and PR in liver S9, respectively. In addition, the cleavage of the methylenedioxy group of the drugs and subsequent methylation or O‐demethylation were also the common metabolic pathways of drugs in liver S9. In addition, the hydroxylation reaction was also the metabolic pathway of AL.ConclusionsThis was the first investigation of in vitro metabolism of AL and PR in rat liver S9. The detailed structural elucidations of AL and PR metabolites were performed using a rapid and accurate HPLC/QqTOFMS method. The metabolic pathways of AL and PR in rat were tentatively proposed based on these characterized metabolites and early reports. Copyright © 2016 John Wiley & Sons, Ltd.
Re‐investigation of the fragmentation of protonated carotenoids by electrospray ionization and nanospray tandem mass spectrometry
Authors: Neto Fausto Carnevale , Guaratini Thais , Costa‐Lotufo Letícia , Colepicolo Pio , Gates Paul J. , Lopes Norberto Peporine 
Published: June 2016

RationaleCarotenoids are polyene isoprenoids with an important role in photosynthesis and photoprotection. Their characterization in biological matrices is a crucial subject for biochemical research. In this work we report the full fragmentation of 16 polyenes (carotenes and xanthophylls) by electrospray ionization tandem mass spectrometry (ESI‐CID‐MS/MS) and nanospray tandem mass spectrometry (nanoESI‐CID‐MS/MS).MethodsAnalyses were carried out on a quadrupole time‐of‐flight (QTOF) mass spectrometer coupled with a nanoESI source and on a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer with an ESI source. The formulae of the product ions were determined by accurate‐mass measurements.ResultsIt is demonstrated that the fragmentation routes observed for the protonated carotenoids derive essentially from charge‐remote fragmentations and pericyclic rearrangements, such as electrocyclic and retro‐ene eliminations (assisted or not by a sigmatropic hydrogen shift). All mechanisms are dependent on cis‐trans isomerization through the formation of several conjugated polyene carbocation intermediates. Some specific ions for the carotenoid epoxides were justified through formation of cyclic oxonium ions.ConclusionsComplete fragmentation pathways of protonated carotenoids by ESI‐ and nanoESI‐CID‐MS/MS provided structural information about functional groups, polyene chain and double bonds, and contribute to identification of carotenoids based on MS/MS fragmentation patterns. Copyright © 2016 John Wiley & Sons, Ltd.
Effects of lipid extraction and ultrafiltration on stable carbon and nitrogen isotopic compositions of fish bone collagen
Authors: Guiry Eric J. , Szpak Paul , Richards Michael P. 
Published: June 2016

RationaleFish bone collagen isotopic measurements are increasingly important in palaeodietary and paleoenvironmental studies yet differences in the chemical and physical properties of fish relative to other vertebrate bones are rarely considered. Lipid content in fish bone, which can exceed 50%, may underlie the poor collagen integrity criteria typically observed in archaeological studies.MethodsWe compare stable carbon and nitrogen isotopic and elemental compositions of bone collagen prepared using four different methods from a wide range of modern fish species to: (1) assess the extent to which lipid content influences bone collagen δ13C and δ15N values, and (2) evaluate the relative efficacy of chemical (2:1 chloroform/methanol) and physical (30 kDa ultrafilters) methods for removing lipids from bones.ResultsLower δ13C values were observed when the lipid content exceeded 5% of the initial bone mass. The lipid content did not influence the δ15N values. 30 kDa ultrafiltration, a common pretreatment for purifying archaeological collagen, removed fewer lipids and was associated with reduced collagen yields (37% loss) as well as altered amino acid compositions. In contrast, collagen prepared using a 2:1 chloroform/methanol lipid extraction step resulted in significantly improved collagen yields, elemental compositions, and isotopic measurements relative to a control treatment.ConclusionsThe chemical lipid extraction method (2:1 chloroform/methanol) performed significantly better than the physical lipid extraction method (30 kDa ultrafilters). Given the high quantities of lipids in fish bones we recommend the inclusion of a chemical lipid extraction step when isolating collagen from modern and archaeological fish bones. Copyright © 2016 John Wiley & Sons, Ltd.
Dual‐spray hydrogen/deuterium exchange (HDX) reactions: A new method of probing protein structure
Authors: Rashid Shaan , Overton Sean , Mazigh Bihac , Mayer Paul M. 
Published: June 2016

RationaleTraditionally, hydrogen/deuterium exchange (HDX) reactions are done in the solution phase. This usually involves incubating the protein with a suitable deuterating agent then acidifying the solution to quench the reaction. A more efficient method may be to conduct the reaction within the ion source of a mass spectrometer and subsequently analyze the products.MethodsUsing the two electrospray emitters equipped on the Waters Synapt G1 mass spectrometer, HDX reactions were conducted within the ion source region in a controlled fashion (‘dual‐spray’). Peptide and protein solutions were electrosprayed through one emitter and the deuterating agent D2O through the secondary electrospray emitter. For the relatively small peptides, Phe‐Leu‐Glu‐Glu‐Leu and oxytocin, the yield of products was calculated using deconvolution functions. Electrospray ionization (ESI) charge‐state distributions and average number of deuterium exchanges were used to probe secondary and tertiary structures of ubiquitin, lysozyme, and cytochrome c in their native and unfolded states.ResultsClear shifts in isotope distributions indicated HDX occurring within the ion source. By ion mobility, simultaneous deuterium exchange for two isobaric species, the oxytocin monomer and dimer, was observed. For denatured ubiquitin, the 12+ and 13+ charge states have a lower average number of exchanges relative to the lower charge states which indicates that these charge states have segments which restrict the access of D2O. Lysozyme has a linear relationship between the charge state and the average number of exchanges, indicating that lysozyme becomes increasingly unfolded as the charge state increases. The dual‐spray HDX method was paired to high‐performance liquid chromatography (HPLC) to demonstrate the applicability of the technique for probing gas‐phase structures in protein mixtures.ConclusionsESI droplets formed from a secondary emitter penetrate primary ESI droplets and change the solvent composition. Dual‐spray HDX is demonstrated to be a more efficient method for probing the structure of proteins than solution‐phase HDX since the acid quenching step can be surpassed. Copyright © 2016 John Wiley & Sons, Ltd.
Mass bias corrections for U‐Pb isotopic analysis by secondary ion mass spectrometry: Implications for U‐Pb dating of uraninite
Authors: Sharpe Ryan , Fayek Mostafa 
Published: June 2016

RationaleUranium (U)‐lead (Pb) geochronology of uraninite is critical to the study of the genesis of U deposits throughout the world. Previous attempts at developing a technique to date uraninite using secondary ion mass spectrometry (SIMS) have, however, had limited success. Improper correction of mass bias results in incorrect reported U‐Pb ratios. When these results are plotted on Concordia diagrams they produce erroneous ages, complicating the study of U deposits.MethodsUranium and Pb isotope ratios were measured in three uraninite reference materials (RMs) with varying Pb content and three samples with unknown U‐Pb isotope compositions using a CAMECA 7f SIMS instrument. Measurements were made using a primary beam of O– accelerated at 12.5 kV. A mass resolving power of 1300 and a 50‐V offset were used to minimize interferences.ResultsThe study demonstrates that the mass bias for U‐Pb isotope ratio measurements in uraninite by SIMS varies as a function of Pb content. A three‐point calibration curve was developed using uraninite RMs with low‐, intermediate‐ and high‐Pb contents. Corrected ratios for both concordant and discordant uraninite were plotted on a Concordia diagram to demonstrate the effect that different correction techniques have on the resulting age.ConclusionsAccurate determination of U‐Pb ratios in uraninite using a SIMS instrument requires a suite of RMs with varying Pb content and the construction of a calibration curve, or a uraninite RM with a Pb content similar to that of the unknowns. Failure to standardize correctly will result in erroneous ages being calculated using Concordia diagrams. Copyright © 2016 John Wiley & Sons, Ltd.
Discrimination of side‐window glass of Korean autos by laser ablation inductively coupled plasma mass spectrometry
Authors: Lee Sin‐Woo , Ryu Jong‐Sik , Min Ji‐Sook , Choi Man‐Yong , Lee Kwang‐Sik , Shin Woo‐Jin 
Published: June 2016

RationaleFragments of glass from cars are often found at crime scenes and can be crucial evidence for solving the crime. The glass fragments are important as trace evidence at crime scenes related to car accidents and burgled homes. By identifying the origin of glass fragments, it is possible to infer the identity of a suspect. Our results represent a promising approach to a thorough forensic investigation of car glass.MethodsThirty‐five samples from the side windows of cars produced and used in South Korea were collected from the official agencies of five car manufacturers and from two glassmakers. In addition, 120 samples from side mirrors were collected from the same suppliers as well as from small businesses. Their chemical compositions (including Pb isotopes) were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) and linear discriminant analysis (LDA) was performed.ResultsThe percentages of major elements (Si, Ca, and Fe) in side‐window glass varied within narrow ranges (30.0 ± 2.36%, 5.93 ± 0.52%, and 0.33 ± 0.05%, respectively), while the differences among Pb isotope ratios were not significant. In contrast, light rare earth elements (LREEs) were different from each glassmaker. From the LDA, the types of side‐window glass were successfully discriminated according to car manufacturer, glassmaker, and even glass thickness. However, glass from side mirrors cannot be used for good forensic identifiers.ConclusionsDiscrimination techniques for side‐window glass, although not for side mirrors, using chemical compositions combined with multivariate statistical analyses provide evidence for forensic investigations. Copyright © 2016 John Wiley & Sons, Ltd.
Atmospheric solids analysis probe mass spectrometry for the rapid identification of pollens and semi‐quantification of flavonoid fingerprints
Authors: Xiao Xiaoyin , Miller Lance L. , Parchert Kylea J. , Hayes Dulce , Hochrein James M. 
Published: June 2016

RationaleFrom allergies to plant reproduction, pollens have important impacts on the health of human and plant populations, yet identification of pollen grains remains difficult and time‐consuming. Low‐volatility flavonoids generated from pollens cannot be easily characterized and quantified with current analytical techniques.MethodsHere we present the novel use of atmospheric solids analysis probe mass spectrometry (ASAP‐MS) for the characterization of flavonoids in pollens. Flavonoid patterns were generated for pollens collected from different plant types (trees and bushes) in addition to bee pollens from distinct geographic regions. Standard flavonoids (kaempferol and rhamnazin) and those produced from pollens were compared and assessed with ASAP‐MS using low‐energy collision MS/MS. Results for a semi‐quantitative method for assessing the amount of a flavonoid in pollens are also presented.ResultsFlavonoid patterns for pollen samples were distinct with variability in the number and relative abundance of flavonoids in each sample. Pollens contained 2–5 flavonoids, and all but Kochia scoparia contained kaempferol or kaempferol isomers. We establish this method as a reliable and applicable technique for analyzing low‐volatility compounds with minimal sample preparation. Standard curves were generated using 0.2–5 μg of kaempferol; from these experiments, it was estimated that there is approximately 2 mg of kaempferol present in 1 g of P. nigra italica pollen.ConclusionsPollens can be characterized with a simple flavonoid pattern rather than analyzing the whole product pattern or the products‐temperature profiles. ASAP‐MS is a rapid analytical technique that can be used to distinguish between plant pollens and between bee pollens originating from different regions. Copyright © 2016 John Wiley & Sons, Ltd.
Robust Monocular Visual Teach and Repeat Aided by Local Ground Planarity and Color‐constant Imagery
Authors: Clement Lee , Kelly Jonathan , Barfoot Timothy D. 
Published: June 2016

Visual Teach and Repeat (VT&R) allows an autonomous vehicle to accurately repeat a previously traversed route using only vision sensors. Most VT&R systems rely on natively three‐dimensional (3D) sensors such as stereo cameras for mapping and localization, but many existing mobile robots are equipped with only 2D monocular vision, typically for teleoperation. In this paper, we extend VT&R to the most basic sensor configuration—a single monocular camera. We show that kilometer‐scale route repetition can be achieved with centimeter‐level accuracy by approximating the local ground surface near the vehicle as a plane with some uncertainty. This allows our system to recover absolute scale from the known position and orientation of the camera relative to the vehicle, which simplifies threshold‐based outlier rejection and the estimation and control of lateral path‐tracking error—essential components of high‐accuracy route repetition. We enhance the robustness of our monocular VT&R system to common failure cases through the use of color‐constant imagery, which provides it with a degree of resistance to lighting changes and moving shadows where keypoint matching on standard gray images tends to struggle. Through extensive testing on a combined 30 km of autonomous navigation data collected on multiple vehicles in a variety of highly nonplanar terrestrial and planetary‐analogue environments, we demonstrate that our system is capable of achieving route‐repetition accuracy on par with its stereo counterpart, with only a modest tradeoff in robustness.
The Social Lives of Gender and Religion: Implications for Development Policy
Authors: Mee Wendy 
Published: June 2016

AbstractTo date, the literature on ‘gender and development’ has remained largely sequestered from that on ‘religion and development’, and consequently the presence of conceptual problems common to the two fields has gone largely unremarked. This paper identifies three such conceptual problems, here termed categorization, identification and representation. The oversight of common conceptual problems has important implications for the assessment of religion and gender in sustainable development policy. One such effect, I argue, is the consolidation of a narrow range of negative and secularist readings of the potential role of gender and religion in sustainable development. To circumvent conceptualizations that may give rise to prejudicial readings of gender and religion, this paper follows feminist and religious studies scholars in arguing that we conceive of gender and religion as permeable categories and non‐exclusive identities, constituted by diverse discursive elements. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment.
Where are the Animals in Sustainable Development? Religion and the Case for Ethical Stewardship in Animal Husbandry
Authors: Narayanan Yamini 
Published: June 2016

AbstractThe rights of livestock that are designated as food/farm animals have been a blindspot across development discourse and policies in spite of compelling moral (and socio‐ecological) factors. They are regarded as 'resources' to sustain growth, leading to food production systems that support factory farming and invasive animal husbandry practices. The paper argues that religion and sustainable development are unlikely partners in the commodification of animals in these policies. Capitalist‐driven interpretations of religion support the objectification of animals. Sustainable development, an efficiency‐driven growth paradigm, is concerned with the preservation of finite natural resources. Sentient factory farmed animals are seen as infinite resources.Using Christianity and Hinduism as examples, the paper argues that religion can also shape alternative animal husbandry/food production practices, and expand the social justice element of sustainable development to encompass what I term 'sociozoological justice' in economic systems that heavily involve animals. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment.
PAM‐SMEs: process assessment method for small to medium enterprises
Authors: Abushama Hisham M. 
Published: June 2016

AbstractSeveral software process improvement (SPI) standard models have been invented since the last decades, for example, CMMI, SPICE, and CMM. Most of these models had to be tailored by several researchers in order to be applied within Small to Medium Enterprises (SMEs). This is mainly due to their environmental challenges such as resources. In addition to this, the SPI models including the current standard model the CMMI are not considering tailoring their SPI program to business objectives. Achieving business objectives is the main recipe for business success. Therefore, this research (PAM‐SMEs) is setup to tailor SPI program to business objectives within SMEs environmental challenges. Key features of the PAM‐SMEs are as follows: the use of simplified and tailorable assessment techniques and data collection tool based on the CMMI; and then prioritizing the outcome of the assessment to the SMEs business objectives by the use of prioritization technique. The PAM‐SMEs was applied within three partner SMEs, and the overall evaluation shows that the PAM‐SMEs help to drive their SPI program toward their business objectives with the available resources. Copyright © 2016 John Wiley & Sons, Ltd.
Strategy for Molecular Design of Photochromic Diarylethenes Having Thermal Functionality
Authors: Kitagawa Daichi , Kobatake Seiya 
Published: June 2016

AbstractThermal reactivities of photochromic diarylethene closed‐ring isomers can be controlled by the introduction of substituents at the reactive positions. Diarylethenes having bulky alkyl groups undergo thermal cycloreversion reactions. When bulky alkoxy groups are introduced, the diarylethenes have both thermal cycloreversion reactivities and low photocycloreversion quantum yields. Such photochromic compounds can be applied to thermally reusable photoresponsive‐image recordings. The thermal cycloreversion reactivity of the closed‐ring isomers can be evaluated using specific steric substituent constants and be correlated with the parameters. By introduction of trimethylsilyl or methoxymethyl groups at the reactive positions, the diarylethene closed‐ring isomers undergo thermal irreversible reactions to produce by‐products at high temperatures. These diarylethenes may be useful for secret‐image recordings. Furthermore, thiophene‐S,S‐dioxidized diarylethenes having secondary alkyl groups at the reactive positions undergo thermal by‐product formation reactions, in addition to the photostability of the colored closed‐ring isomers. Such materials may be used for light‐starting thermosensors. The thermal by‐product formation reactivity can be evaluated by the specific substituent constants and theoretical calculations of quantum chemistry. These results supply the strategy for the molecular design of the photochromic diarylethenes having thermal functionality.
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