bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclodextrin‐mediated enantioseparation of phenylalanine amide derivatives and amino alcohols by capillary electrophoresis—Role of complexation constants and complex mobilities
Authors: Aranyi Anita , Péter Antal , Ilisz István , Fülöp Ferenc , Scriba Gerhard K. E. 
Published: May 2014

The separation of the enantiomers of phenylalanine amide and N‐methyl derivatives as well as some amino alcohols was studied by CE in acidic BGEs using CDs as chiral selectors. The native CDs displayed only low chiral recognition ability at a concentration of 15 mg/mL in 20 mM sodium phosphate buffer, pH 2.5. In contrast, the analyte enantiomers were separated in the presence of randomly sulfated CDs under reversed polarity of the applied voltage. Sulfated β‐CD proved to be the most universal selector resulting in the enantioseparation of all analytes. Opposite enantiomer migration order depending on the size of the CD cavity was observed for phenylalanine amide and 2‐amino‐2‐phenylethanol. The R‐enantiomers migrated first in the presence of sulfated α‐CD and γ‐CD while the S‐enantiomers were detected first in the presence of sulfated β‐CD. The enantioseparations could be rationalized based on analyte complexation by the respective CDs except for 2‐amino‐2‐phenylethanol and sulfated β‐CD where essentially equal complexation constants were derived for the enantiomers. In this case, the migration behavior could be attributed to the mobilities of the enantiomer–CD complexes adding another example to the CE‐specific phenomenon of enantioseparations based primarily on complex mobilities.
Properties of modern dust accumulating in the Uinta Mountains, Utah, USA, and implications for the regional dust system of the Rocky Mountains
Authors: Munroe Jeffrey S. 
Published: May 2014

ABSTRACTA growing body of work is illuminating the importance of dust as a component of soil development and biogeochemical cycling in alpine environments of the Rocky Mountains. Nonetheless, important questions remain about the dust system in this region due to a paucity of focused studies and direct measurements. This project involved deployment of modified marble dust traps in the alpine zone of the Uinta Mountains of Utah to trap modern atmospheric dust over a two year period. Results indicate that dust accumulation rates are similar to values previously reported for the Wind River Range of Wyoming, but less than values for south‐western Colorado, suggesting a south‐to‐north decrease in regional dust flux. The overall mean grain size of Uinta dust is similar to values reported by prior studies in Colorado, indicating a general uniformity in grain size distribution. Uinta dust is dominated by quartz, plagioclase, K‐feldspar, and illite with trace amounts of kaolinite, chlorite, and amphibole. In contrast, only quartz and K‐feldspar are present in the Uinta bedrock, confirming an exotic origin for the dust arriving in the alpine zone. Exotic mineralogies have also been reported in dust from other mountain ranges in the western United States, indicating that eolian delivery of allochthonous minerals is a widespread process. Geochemical analysis reveals that Bi, Na, P, Zn, Sn, Cu, Cd, Ba, Ni, W, Sb, Pb, and Tl in Uinta dust are elevated 10 to > 80‐times above their abundances in local bedrock. These results support reports of anthropogenic elemental enrichment in lake sediments from Colorado and Utah. Patterns of elemental loading suggest that certain elements are delivered by winds arriving from different directions, raising the possibility that some elements could be associated with unique source areas. Copyright © 2014 John Wiley & Sons, Ltd.
Mitigating systematic error in topographic models derived from UAV and ground‐based image networks
Authors: James Mike R. , Robson Stuart 
Published: May 2014

ABSTRACTHigh resolution digital elevation models (DEMs) are increasingly produced from photographs acquired with consumer cameras, both from the ground and from unmanned aerial vehicles (UAVs). However, although such DEMs may achieve centimetric detail, they can also display systematic broad‐scale error that restricts their wider use. Such errors which, in typical UAV data are expressed as a vertical ‘doming’ of the surface, result from a combination of near‐parallel imaging directions and inaccurate correction of radial lens distortion. Using simulations of multi‐image networks with near‐parallel viewing directions, we show that enabling camera self‐calibration as part of the bundle adjustment process inherently leads to erroneous radial distortion estimates and associated DEM error. This effect is relevant whether a traditional photogrammetric or newer structure‐from‐motion (SfM) approach is used, but errors are expected to be more pronounced in SfM‐based DEMs, for which use of control and check point measurements are typically more limited. Systematic DEM error can be significantly reduced by the additional capture and inclusion of oblique images in the image network; we provide practical flight plan solutions for fixed wing or rotor‐based UAVs that, in the absence of control points, can reduce DEM error by up to two orders of magnitude. The magnitude of doming error shows a linear relationship with radial distortion and we show how characterization of this relationship allows an improved distortion estimate and, hence, existing datasets to be optimally reprocessed. Although focussed on UAV surveying, our results are also relevant to ground‐based image capture. © 2014 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
Relationships between exposure and dose in aquatic toxicity tests for organic chemicals
Authors: Mackay Donald , McCarty Lynn S. , Arnot Jon A. 
Published: May 2014

Abstract

There is continuing debate about the merits of exposure-based toxicity metrics such as median lethal concentration (LC50) versus organism-based metrics such as critical body residue (CBR) as indicators of chemical toxicity to aquatic organisms. To demonstrate relationships and differences between these 2 metrics, the authors applied a simple one-compartment toxicokinetic mass-balance model for water-exposed fish for a series of hypothetical organic chemicals exhibiting baseline narcotic toxicity. The authors also considered the influence of several toxicity-modifying factors. The results showed that the results of standard toxicity tests, such as the LC50, are strongly influenced by several modifying factors, including chemical and organism characteristics such as hydrophobicity, body size, lipid content, metabolic biotransformation, and exposure durations. Consequently, reported LC50s may not represent consistent dose surrogates and may be inappropriate for comparing the relative toxicity of chemicals. For comparisons of toxicity between chemicals, it is preferable to employ a delivered dose metric, such as the CBR. Reproducible toxicity data for a specific combination of chemical, exposure conditions, and organism can be obtained only if the extent of approach to steady state is known. Suggestions are made for revisions in test protocols, including the use of models in advance of empirical testing, to improve the efficiency and effectiveness of tests and reduce the confounding influences of toxicity-modifying factors, especially exposure duration and metabolic biotransformation. This will assist in linking empirical measurements of LC50s and CBRs, 2 different but related indicators of aquatic toxicity, and thereby improve understanding of the large existing database of aquatic toxicity test results. Environ Toxicol Chem 2014; 33:2038–2046. © 2014 SETAC
Measurement of naphthenic acids in the receiving waters around an offshore oil platform by passive sampling
Authors: Harman Christopher , Langford Katherine , Sundt Rolf C. , Brooks Steven 
Published: May 2014

Abstract

Polar organic chemical integrative samplers (POCIS) were deployed in the vicinity of an offshore oil installation and analyzed for naphthenic acids (NAs). The POCIS accumulated a range of mono- to tetracyclic NAs, with different degrees of alkylation, with monocyclic acids being the most abundant. Currently, POCIS or similar polar samplers may be the only way to measure exposure to NAs from offshore discharges in situ. In addition, they may be a valuable tool for monitoring similar organic acids in general. Environ Toxicol Chem 2014; 33:1946–1949. © 2014 SETAC
T3‐T4 laryngeal cancer in The Netherlands Cancer Institute; 10‐year results of the consistent application of an organ‐preserving/‐sacrificing protocol
Authors: Timmermans Adriana J. , de Gooijer Cornedine J. , Hamming–Vrieze Olga , Hilgers Frans J.M. , van den Brekel Michiel W.M. 
Published: May 2014

ABSTRACTBackgroundBoth organ‐preserving concurrent (chemo)radiotherapy ((C)RT) and organ‐sacrificing surgery (total laryngectomy) are used for treatment of advanced laryngeal cancer. The purpose of this study was to present the assessment of our treatment protocol for T3 (C)RT and T4 disease (total laryngectomy + postoperative RT).MethodsWe conducted a retrospective cohort study in 182 consecutive patients (1999–2008). The primary outcome was overall survival (OS) in relation to stage and treatment.ResultsOne hundred two patients received RT (82.4% T3), 20 patients CRT (60.0% T3), and 60 patients total laryngectomy + RT (91.7% T4). Five‐year OS: T3 52%, T4 48%, for RT 50%, for CRT 43%, and for total laryngectomy + RT 52%. Five‐year laryngectomy‐free interval was 72% after RT, and 83% after CRT.ConclusionThere were no differences in survival according to T classification or treatment modality. Because the majority of T3 laryngeal cancers were treated with (C)RT and the majority of T4 with total laryngectomy + RT, this gives food for thought on whether the present protocol for T3 laryngeal cancer is optimal. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1495–1503, 2015
A Stimulation Method to Assess the Contractile Status of the Lumbar Extensors in a Seated Posture
Authors: Jia Bochen , Nussbaum Maury A. , Agnew Michael J. 
Published: May 2014

AbstractThe purpose of present study was to develop and evaluate methods to assess stimulation responses of the lumbar extensors, as part of a longer‐term goal of detecting fatigue during prolonged sitting. Three stimulation frequencies (2, 5, and 8 Hz) were tested in separate stages, which include 3 stimulation trains and 4 sampling blocks. Repeated measures analyses of variance were used to determine whether any significant differences in mean stimulation responses occurred with respect to stimulation frequency, sampling block, and stimulation train. Reliability of measured stimulation responses was assessed within and between sampling blocks using intraclass correlation coefficients. Stimulation frequencies significantly affected the stimulation responses and time‐to‐potentiation differed between the 3 stimulation frequencies; it was highest for 2 Hz stimulation. All 3 stimulation frequencies resulted in excellent reliability within and between sampling blocks. Use of the current protocol at 2 Hz is recommended as appropriate to measure the lumbar extensors status during prolonged sitting.
Exposure vs. response of blood pressure in patients with rheumatoid arthritis following treatment with fostamatinib
Authors: Boström Emma , Öhrn Fredrik , Hanze Eva , Sandström Marie , Martin Paul , Wählby‐Hamrén Ulrika 
Published: June 2014

AbstractFostamatinib is an oral spleen tyrosine kinase (SYK) inhibitor which has been evaluated as a potential treatment for rheumatoid arthritis (RA). Treatment with fostamatinib has been associated with an increase in blood pressure (BP). In this work, we present a pooled analysis of the pharmacokinetic–pharmacodynamic (PKPD) relationship for BP, based on 3 Phase III studies, aiming to increase the knowledge about fostamatinib's effect on BP in the RA population. Fostamatinib is rapidly and extensively converted to R406 after oral administration of fostamatinib, and the PK of R406 could be described by a two‐compartment population PK model with first order absorption, with an estimated CL/F of 18.7 L/h. Average steady‐state concentrations, predicted based on the individual CL/F estimates, were subsequently used in the PKPD analysis. The population PKPD analysis revealed a concentration dependent increase of BP with increasing R406 concentrations, where a power model and an Emax model best described the increase in SBP and DBP, respectively. The predicted increases were +5.2 mmHg for SBP and +4.2 mmHg for DBP, for a 100 mg bid dose. The impact of covariates on the PKPD relationship was investigated but covariates did only explain a minor part of the overall high variability in BP.
The upper cretaceous snake Dinilysia patagonicaSmith‐Woodward, 1901, and the crista circumfenestralis of snakes
Authors: Palci Alessandro , Caldwell Michael W. 
Published: June 2014

ABSTRACTStudies on the phylogenetic relationships of snakes and lizards are plagued by problematic characterizations of anatomy that are then used to define characters and states in taxon‐character matrices. State assignments and character descriptions must be clear characterizations of observable anatomy and topological relationships if homologies are to be hypothesized. A supposed homology among snakes, not observed in lizards, is the presence of a crista circumfenestralis (CCF), a system of bony crests surrounding the fenestra ovalis and lateral aperture of the recessus scalae tympani. We note that there are some fossil and extant snakes that lack a CCF, and some extant lizards that possess a morphological equivalent. The phylogenetically important upper Cretaceous fossil snake Dinilysia patagonica has been interpreted by different authors as either having or lacking a CCF. These conflicting results for Dinilysia were tested by re‐examining the morphology of the otic region in a large sample of snakes and lizards. An unambiguous criterion arising from the test of topology is used to define the presence of a CCF: the enclosure of the ventral margin of the juxtastapedial recess by flanges of the otoccipital (crista tuberalis and crista interfenestralis) that extend forward to contact the posterior margin of the prootic. According to this criterion D. patagonica does not possess a CCF, therefore, this anatomical feature must have arisen later during the evolution of snakes. J. Morphol. 275:1187–1200, 2014. © 2014 Wiley Periodicals, Inc.
The effects of ENSO under negative AO phase on spring dust activity over northern China: an observational investigation
Authors: Lee Yun Gon , Kim Jhoon , Ho Chang‐Hoi , An Soon‐Il , Cho Hi‐Ku , Mao Rui , Tian Baijun , Wu Dong , Lee Jae N. , Kalashnikova Olga , Choi Yunsoo , Yeh Sang‐Wook 
Published: June 2014

ABSTRACTThe effects of El Niño/Southern Oscillation (ENSO) under negative Arctic Oscillation (AO) phase on the Asian dust activity are investigated for springs of the period 1961–2002. The spring dust index (DI) describing the monthly frequencies of three types of dust events (e.g. dust storm, blowing dust, and floating dust) exhibits a significant increase in the years of negative AO phase (hereafter AO−) and El Niño, compared with that in the years of AO− and La Niña. Averaged over all observation stations, the spring DI (49.7) during the El Niño/AO− years is higher by 11.4% or 29.8% than that (38.3) during the La Niña/AO− years. We suggest possible physical mechanism that the anomalous large‐scale environments associated with AO− and El Niño are more effective to provide favourable conditions to enhance Asian dust activity. During the El Niño/AO− years, meridional gradients of pressure and temperature over the dust source regions are significantly enhanced by decreasing the geopotential height and warming air temperature that originated from the north and south of source regions, respectively, under the influence of AO− and El Niño. These also intensify the zonal wind shear and atmospheric baroclinicity, thereby producing enhanced cyclogenesis and dust occurrences over the major source regions. At the same time, dust transport paths with the stronger westerly winds are developed by the combined constraints of anomalous cyclone over the Siberia and the Mongolia and anomalous anticyclone over the western North Pacific, and thus strengthen dust transport to the downwind regions.
A stabilized iterative scheme for coupled hydro‐mechanical systems using reproducing kernel particle method
Authors: Xie Yongning , Wang Gang 
Published: June 2014

SUMMARYIn this paper, a novel iterative coupling scheme is developed for solving coupled hydro‐mechanical problems using reproducing kernel particle method. The numerical scheme calls the fluid and the solid solvers sequentially and iteratively until convergent solutions are obtained. To overcome the numerical instability problem, a simple stabilization technique is developed and proved to be unconditionally stable through stability analysis. The accuracy and convergence of the proposed numerical scheme are demonstrated through extensive parametric studies of one‐dimensional and two‐dimensional consolidation simulations using fully saturated elastic medium as well as biaxial test using a fully nonlinear soil model. Copyright © 2014 John Wiley & Sons, Ltd.
Application of a fast sorting algorithm to the assignment of mass spectrometric cross‐linking data
Authors: Petrotchenko Evgeniy V. , Borchers Christoph H. 
Published: June 2014

Cross‐linking combined with MS involves enzymatic digestion of cross‐linked proteins and identifying cross‐linked peptides. Assignment of cross‐linked peptide masses requires a search of all possible binary combinations of peptides from the cross‐linked proteins’ sequences, which becomes impractical with increasing complexity of the protein system and/or if digestion enzyme specificity is relaxed. Here, we describe the application of a fast sorting algorithm to search large sequence databases for cross‐linked peptide assignments based on mass. This same algorithm has been used previously for assigning disulfide‐bridged peptides (Choi et al., ), but has not previously been applied to cross‐linking studies.
Transformation of codeine and codeine‐6‐glucuronide to opioid analogues by urine adulteration with pyridinium chlorochromate: potential issue for urine drug testing
Authors: Luong Susan , Ung Alison T. , Kalman John , Fu Shanlin 
Published: June 2014

RATIONALEPyridinium chlorochromate (PCC) is the active ingredient of 'Urine Luck', a commercially available in vitro adulterating agent used to conceal the presence of drugs in a urine specimen. The exposure of codeine and its major glucuronide metabolite codeine‐6‐glucuronide (C6G) to PCC was investigated to determine whether PCC is an effective masking agent for these opiate compounds.METHODSFollowing the addition of PCC to both spiked and authentic codeine and C6G‐positive urine specimens, the samples were monitored using liquid chromatography/mass spectrometry (LC/MS). Stable reaction products were identified and characterized using high‐resolution MS analysis and, where possible, nuclear magnetic resonance (NMR) analysis.RESULTSIt was determined that PCC effectively oxidizes codeine and C6G, thus altering the original codeine‐to‐C6G ratio in the urine specimen. Four reaction products were identified for codeine: codeinone, 14‐hydroxycodeinone, 6‐O‐methylcodeine and 8‐hydroxy‐7,8‐dihydrocodeinone. Similarly, three reaction products were identified for C6G: codeinone, codeine and a lactone of C6G (tentative assignment).CONCLUSIONSBesides addressing the complications added to interpretation, more investigation is warranted to further determine their potential for use as markers for monitoring the presence of codeine and C6G in urine specimens adulterated with PCC. Copyright © 2014 John Wiley & Sons, Ltd.
Capillary atmospheric pressure chemical ionization using liquid point electrodes
Authors: Klee Sonja , Thinius Marco , Brockmann Klaus J. , Benter Thorsten 
Published: June 2014

RATIONALEAtmospheric pressure chemical ionization (APCI) sources operated with point to plane DC discharges ('Coronas') frequently suffer from point electrode degradation and potentially lead to oxidation and/or fragmentation of the generated analyte ions. It is postulated that these adverse effects are caused by the interaction of these ions with the discharge chemistry as well as en route to the mass analyzer region.METHODSThe corona discharge metal point electrode is replaced by the conically shaped liquid effluent evolving from a fused‐silica capillary, which is analogous but not identical to the Taylor cone formation in electrospray ionization. The liquid consisting of either pure water or water containing 0.1 %V formic acid is fed via a nano‐flow delivery stage at typical flow rates between 1–800 μL/h. The liquid flow is continuously replenishing the surface of the point electrode. The source is directly coupled to the inlet capillary of appropriate mass spectrometers, e.g., the Bruker Daltonics and Agilent varieties.RESULTSThe actively pumped liquid flow is supplying a constant amount of the reagent gas (H2O) to the corona region in the 20 ppmV to 30 %V range, leading to controlled, very stable operation of the source. The typical light emission observed for corona discharges is in very close proximity to the aqueous surface. Analyte protonation is the dominating ionization pathway. The degree of primary analyte fragmentation is extremely low.CONCLUSIONSWe have developed a novel atmospheric pressure chemical ionization source designed for the hyphenation of nano‐flow liquid chromatography and gas chromatography with atmospheric pressure ionization mass spectrometry. The proposed reaction mechanism including the electrochemistry occurring in the source along with formation of protonated analyte molecules via collision‐induced dissociation (CID) is in full accord with the experimental results. The system exhibits an extremely stable performance over prolonged operation times, sole generation of protonated molecules, and low degree of analyte ion fragmentation. Copyright © 2014 John Wiley & Sons, Ltd.
Metabonomics of human fecal extracts characterize ulcerative colitis, Crohn’s disease and healthy individuals
Authors: Bjerrum Jacob Tveiten , Wang Yulan , Hao Fuhua , Coskun Mehmet , Ludwig Christian , Günther Ulrich , Nielsen Ole Haagen 
Published: May 2014

Abstract
This study employs spectroscopy-based metabolic profiling of fecal extracts from healthy subjects and patients with active or inactive ulcerative colitis (UC) and Crohn’s disease (CD) to substantiate the potential use of spectroscopy as a non-invasive diagnostic tool and to characterize the fecal metabolome in inflammatory bowel disease (IBD). Stool samples from 113 individuals (UC 48, CD 44, controls 21) were analyzed by 1H nuclear magnetic resonance (NMR) spectroscopy (Bruker 600 MHz, Bruker BioSpin, Rheinstetten, Germany). Data were analyzed with principal component analysis and orthogonal-projection to latent structure-discriminant analysis using SIMCA-P + 12 and MATLAB. Significant differences were found in the metabolic profiles making it possible to differentiate between active IBD and controls and between UC and CD. The metabolites holding differential power primarily belonged to a range of amino acids, microbiota-related short chain fatty acids, and lactate suggestive of an inflammation-driven malabsorption and dysbiosis of the normal bacterial ecology. However, removal of patients with intestinal surgery and anti-TNF-α antibody treatment eliminated the discriminative power regarding UC versus CD. This study consequently demonstrates that 1H NMR spectroscopy of fecal extracts is a potential non-invasive diagnostic tool and able to characterize the inflammation-driven changes in the metabolic profiles related to malabsorption and dysbiosis. Intestinal surgery and medication are to be accounted for in future studies, as it seems to be factors of importance in the discriminative process.