bluuebunny/crossref_metadata_2025 huggingface dataset:
Connectivity and runoff dynamics in heterogeneous basins
Authors: Phillips R. W. , Spence C. , Pomeroy J. W.
Published: April 2011

A drainage basin's runoff response can be determined by the connectivity of generated runoff to the stream network and the connectivity of the downstream drainage network. The connectivity of a drainage basin modulates its ability to produce streamflow and respond to precipitation events and is a function of the complex and variable storage capacities throughout the drainage basin and along the drainage network. An improved means to measure and account for the dynamics of stream network connectivity at the catchment scale is needed to predict basin scale streamflow. At a 150 km2 subarctic Precambrian Shield catchment where the poorly drained heterogeneous mosaic of lakes, exposed bedrock, and soil filled areas creates variable contributing areas, hydrological connectivity was measured in 11 sub‐basins with a particular focus on three representative sub‐basins. The three sub‐basins, although of similar relative size, vary considerably in the dominant typology and topology of their constituent elements. At a 10‐m spatial resolution, saturated areas were mapped using both multispectral satellite imagery and onsite measurements of storage according to land cover. To measure basin‐scale hydrological connectivity, the drainage network was represented using graph theory where stream reaches are ‘edges’ connecting sub‐basin ‘nodes’. The overall hydrological connectivity of the stream network was described as the ratio of actively flowing relative to potentially flowing stream reaches. The hydrological connectivity of the stream network to the outlet was described as the ratio of actively flowing stream reaches that were connected to the outlet to the potentially flowing stream reaches. Hydrological connectivity was then related to daily average streamflow and basin runoff ratio. Improved understanding of causal factors for the variable streamflow response to runoff generation in this environment will serve as a first step towards improved streamflow prediction in formerly glaciated landscapes, especially in small ungauged basins. Copyright © 2011 John Wiley & Sons, Ltd.
Origin of salinity in a multilayered aquifer with high salinization vulnerability
Authors: Gassama Nathalie , Dia Aline , Violette Sophie
Published: April 2011

The Kaluvelly watershed is a coastal area (Tamil Nadu, India) where water abstraction has resulted in a dramatic fall in the level of the water table and a piezometric depression in the most exploited aquifer, the Vanur aquifer. In addition, intensification/mechanization of agriculture may have affected the quality of recharge water. An initial hydrodynamic study showed that the Vanur aquifer is highly vulnerable to salinization due to potential seawater intrusion, and our aim was to determine the source of salinity recorded in the groundwater of this multilayered aquifer. Our approach involved the use of existing boreholes and of a moderate number of samples, with the aim of developing appropriate water resource management techniques. Major element, 18O/16O, 2H/1H and 87Sr/86Sr, ratios were measured in rainwater, surface water and groundwater collected during five sampling campaigns over a 2‐year period. Geochemical data indicate that the Vanur aquifer is recharged and that small mixings between aquifers fluctuate according to monsoon intensity. There was no evidence of seawater intrusion. The range of recorded salinity originated mainly from water–rock interaction but a disconnection of some deeper parts of the aquifer was apparent. Strontium isotopic ratios in the recharge area suggest an anthropogenic influence, possibly related to fertilizer use. A high SO4/Cl ratio was observed in the aquifer; in the deeper parts, the influence of a formation containing lignite is hypothesized, whereas near the surface, sulphate may partly originate from fertilizer use and fossil fuel combustion. Water isotopic data suggest that the origin of precipitation in this region has been unchanged for several hundreds or thousands of years. Copyright © 2011 John Wiley & Sons, Ltd.
A preliminary assessment of the spatial sources of contemporary suspended sediment in the Ohio River basin, United States, using water quality data from the NASQAN programme in a source tracing procedure
Authors: Zhang Y. S. , Collins A. L. , Horowitz A. J.
Published: April 2011

Reliable information on catchment scale suspended sediment sources is required to inform the design of management strategies for helping abate the numerous environmental issues associated with enhanced sediment mobilization and off‐site loadings. Since sediment fingerprinting techniques avoid many of the logistical constraints associated with using more traditional indirect measurement methods at catchment scale, such approaches have been increasingly reported in the international literature and typically use data sets collected specifically for sediment source apportionment purposes. There remains scope for investigating the potential for using geochemical data sets assembled by routine monitoring programmes to fingerprint sediment provenance. In the United States, routine water quality samples are collected as part of the US Geological Survey's revised National Stream Quality Accounting Network programme. Accordingly, the geochemistry data generated from these samples over a 10‐year period (1996–2006) were used as the basis for a fingerprinting exercise to assess the key tributary sub‐catchment spatial sources of contemporary suspended sediment transported by the Ohio River. Uncertainty associated with the spatial source estimates was quantified using a Monte Carlo approach in conjunction with mass balance modelling. Relative frequency weighted means were used as an alternative way of summarizing the spatial source contributions, thereby avoiding the need to use confidence limits. The results should be interpreted in the context of the routine, but infrequent nature, of the suspended sediment samples used to assemble geochemistry as a basis for the sourcing exercise. Nonetheless, the study demonstrates how routine monitoring samples can be used to provide some preliminary information on sediment provenance in large drainage basins. Copyright © 2011 John Wiley & Sons, Ltd.
Use of plasma exchange in patients with heparin‐induced thrombocytopenia: A report of two cases and a review of the literature
Authors: Jaben Elizabeth A. , Torloni A. Sergio , Pruthi Rajiv K. , Winters Jeffrey L.
Published: April 2011

Heparin‐induced thrombocytopenia (HIT), which is characterized by thrombocytopenia and potentially serious thromboses, may develop in patients exposed to heparin anticoagulation. HIT is caused by antibodies to the heparin/platelet factor 4 (PF4) complex. Management of HIT involves discontinuation of heparin and anticoagulation with a nonheparin alternative such as a direct thrombin inhibitor (DTI). This poses a challenge in the management of patients who need to undergo cardiopulmonary bypass surgery (CPB), because CPB requires anticoagulation with heparin and standardized protocols for use of DTIs are not widely available. We report two patients with HIT who underwent successful CPB with heparin anticoagulation following plasma exchange (PE) to reduce heparin/PF4 antibody titers. Case 1 is a 46‐year‐old male with cardiac amyloidosis who needed urgent placement of a left ventricular assist device. Case 2 is a 34‐year‐old woman with acute myocarditis who needed placement of a biventricular assist device. Both patients had positive enzyme‐linked immunosorbent assay assays for heparin/PF4 antibodies and clinical evidence of HIT before PE. Following PE and subsequent CPB, neither patient had clinical or laboratory evidence of HIT. The literature regarding the use of PE for the treatment of complications of HIT and as prophylaxis before CPB is reviewed. J. Clin. Apheresis, 2011. © 2011 Wiley‐Liss, Inc.
The ocular skeleton through the eye of evo‐devo
Authors: Franz‐Odendaal Tamara Anne
Published: April 2011

An evolutionary developmental (evo‐devo) approach to understanding the evolution, homology, and development of structures has proved important for unraveling complex integrated skeletal systems through the use of modules, or modularity. An ocular skeleton, which consists of cartilage and sometimes bone, is present in many vertebrates; however, the origin of these two components remains elusive. Using both paleontological and developmental data, I propose that the vertebrate ocular skeleton is neural crest derived and that a single cranial neural crest module divided early in vertebrate evolution, possibly during the Ordovician, to give rise to an endoskeletal component and an exoskeletal component within the eye. These two components subsequently became uncoupled with respect to timing, placement within the sclera and inductive epithelia, enabling them to evolve independently and to diversify. In some extant groups, these two modules have become reassociated with one another. Furthermore, the data suggest that the endoskeletal component of the ocular skeleton was likely established and therefore evolved before the exoskeletal component. This study provides important insights into the evolution of the ocular skeleton, a region with a long evolutionary history among vertebrates. J. Exp. Zool. (Mol. Dev. Evol.) 316:393–401, 2011. © 2011 Wiley‐Liss, Inc.
Effect of the beta‐sheet‐breaker peptide LPFFD on oriented network of amyloid β25‐35 fibrils
Authors: Murvai Ünige , Soós Katalin , Penke Botond , Kellermayer Miklós S. Z.
Published: April 2011

Amyloid fibrils are self‐associating filamentous structures deposited in extracellular tissue in various neurodegenerative and protein misfolding disorders. It has been shown that beta‐sheet‐breaker (BSB) peptides may interfere with amyloid fibril assembly. Although BSB peptides are prospective therapeutic agents in amyloidosis, there is ambiguity about the mechanisms and generality of their action. In the present work we analyzed the effect of the BSB peptide LPFFD on the growth kinetics, morphologic, and mechanical properties of amyloid β25‐35 (Aβ25‐35) fibrils assembled in an oriented array on mica surface. Aβ25‐35 is thought to represent the biologically active, toxic fragment of the full‐length Aβ peptide. Growth kinetics and morphologic features were analyzed using in situ atomic force microscopy in the presence of various concentrations of LPFFD. We found that the addition of LPFFD only slightly altered the assembly kinetics of Aβ25‐35 fibrils. Already formed fibrils did not disassemble in the presence of high concentrations of LPFFD. The mechanical stability of the fibrils was explored with force spectroscopy methods. The nanomechanical behavior of Aβ25‐35 fibrils is characterized by the appearance of force staircases which correspond to the force‐driven unzipping and dissociation of several protofilaments. In the presence of LPFFD single‐plateau force traces dominated. The effects of LPFFD on Aβ25‐35 fibril assembly and stability suggest that inter‐protofilament interactions were slightly weakened. Complete disassembly of fibrils, however, was not observed. Thus, under the conditions explored here, LPFFD may not be considered as a BSB peptide with generalized beta‐sheet breaking properties. Copyright © 2011 John Wiley & Sons, Ltd.
Tobacco mosaic virus as an AFM tip calibrator
Authors: Trinh Minh‐Hieu , Odorico Michael , Bellanger Laurent , Jacquemond Mireille , Parot Pierre , Pellequer Jean‐Luc
Published: April 2011

The study of high‐resolution topographic surfaces of isolated single molecules is one of the applications of atomic force microscopy (AFM). Since tip‐induced distortions are significant in topographic images the exact AFM tip shape must be known in order to correct dilated AFM height images using mathematical morphology operators. In this work, we present a protocol to estimate the AFM tip apex radius using tobacco mosaic virus (TMV) particles. Among the many advantages of TMV, are its non‐abrasivity, thermal stability, bio‐compatibility with other isolated single molecules and stability when deposited on divalent ion pretreated mica. Compared to previous calibration systems, the advantage of using TMV resides in our detailed knowledge of the atomic structure of the entire rod‐shaped particle. This property makes it possible to interpret AFM height images in term of the three‐dimensional structure of TMV. Results obtained in this study show that when a low imaging force is used, the tip is sensing viral protein loops whereas at higher imaging force the tip is sensing the TMV particle core. The known size of the TMV particle allowed us to develop a tip‐size estimation protocol which permits the successful erosion of tip‐convoluted AFM height images. Our data shows that the TMV particle is a well‐adapted calibrator for AFM tips for imaging single isolated biomolecules. The procedure developed in this study is easily applicable to any other spherical viral particles. Copyright © 2011 John Wiley & Sons, Ltd.
Ice winter severity in the western Baltic Sea in the period of 1301–1500: comparison with other relevant data
Authors: Schmelzer Natalija , Holfort Jürgen
Published: April 2011

A 700‐year time series of ice winter severity index (referred to as Ice Index in this contribution) which additionally includes the period from 1301 to 1500 is now available for the region of the western Baltic. It is compared with air temperature time series, NAO, and other relevant indices. As expected for a regional time series, agreement with larger‐scale northern hemisphere temperature variations is found only on longer time scales. Very good correspondence, even on shorter time scales, is obtained using a geographically close time series of annual mean air temperatures for the Low Countries (The Netherlands and Belgium). Although the data basis for the additionally included 1301–1500 period is quite sparse, there is also very good correspondence in this period. Correlation with the NAO Winter Index is generally negative, but the correlation is not significant for earlier periods. Copyright © 2011 Royal Meteorological Society
Temperature dependence of phonon spectra and structural characteristics in multiferroic LuFe2O4 system
Authors: Hou Y. , Yao Y. P. , Dong S. N. , Teng M. L. , Sun X. F. , Li X. G.
Published: April 2011

The phonon spectra and structural characteristics of the LuFe2O4 system were investigated using X‐ray diffraction as well as Raman and infrared (IR) spectroscopic techniques. Two step‐like anomalies of the wavenumbers of the $E_{\rm {g}}^{3}$ peak in the Raman spectra and the $E_{\rm {u}}^{3}$ peak in IR spectra, as well as some weak anomalies of the lattice parameters, were found around the ferrimagnetic and ferroelectric transition temperatures. The substitutions of Lu with Yb and Fe with Mn lead to the corresponding wavenumber shifts in the optical spectra, which can be attributed to the changes in the atomic mass and lattice parameters. Furthermore, the Raman intensity was found to be related to the changes in the local structure and electrical conductivity. These results illustrate that the structural fluctuations could effectively influence the phonon modes, and a possible interplay among the structural, magnetic, and charge‐ordering properties exists in this multiferroic system. Copyright © 2011 John Wiley & Sons, Ltd.
Raman spectrum of decrespignyite [(Y,REE)4Cu(CO3)4Cl(OH)5·2H2O] and its relation with those of other halogenated carbonates including bastnasite, hydroxybastnasite, parisite and northupite
Authors: Frost Ray L. , Palmer Sara J.
Published: April 2011

Raman spectroscopy complemented with infrared spectroscopy has been used to study the rare‐earth‐based mineral decrespignyite [(Y,REE)4Cu(CO3)4Cl(OH)5· 2H2O] and the spectrum compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of decrespignyite displays three bands at 1056, 1070 and 1088 cm−1 attributed to the CO32− symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of the CO32− symmetric stretching vibration varies with the mineral composition. The Raman spectrum of decrespignyite shows bands at 1391, 1414, 1489 and 1547 cm−1, whereas the Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm−1, respectively, assigned to the ν3 (CO3)2− antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands are observed at 791, 815, 837 and 849 cm−1, which are assigned to the (CO3)2−ν2 bending modes. Raman bands are observed for decrespignyite at 694, 718 and 746 cm−1 and are assigned to the (CO3)2−ν4 bending modes. Raman bands are observed for the carbonate ν4 in‐phase bending modes at 722 cm−1 for bastnasite, 736 and 684 cm−1 for parisite and 714 cm−1 for northupite. Multiple bands are observed in the OH stretching region for decrespignyite, bastnasite and parisite, indicating the presence of water and OH units in the mineral structure. Copyright © 2011 John Wiley & Sons, Ltd.
Corrosion resistance of Zn–Ni/Ni and Ni/Zn–Ni compositionally modulated multilayer coating
Authors: Chen J.‐L. , Liu J.‐H. , Li S.‐M. , Yu M.
Published: April 2011

Zn–Ni/Ni and Ni/Zn–Ni compositionally modulated multilayer (CMM) coatings were prepared by dual‐bath technique. The effects of layers number and sublayers order were studied. Specially, the effect of different sublayers thickness ratios with the same multilayer period (λ) on the corrosion resistance of the CMM coatings was investigated in detail. Results showed that the corrosion resistance of Ni/Zn–Ni (Zn–Ni alloy sublayer as the top layer) CMM coating was better than that of Zn–Ni/Ni (Ni sublayer as the top layer) CMM coating. The 6‐layer CMM coating with the layer thickness ratio of Ni/Zn–Ni = 0.8:1.2 (λ = 2 µm) has the best corrosion resistance.
Study of the correlation between corrosion resistance and semi‐conducting properties of the passive film of AISI 316L stainless steel in physiological solution
Authors: Antunes R. A. , de Oliveira M. C. L. , Costa I.
Published: April 2011

In this work the corrosion resistance of AISI 316L biomedical stainless steel was assessed through electrochemical impedance spectroscopy (EIS) measurements in Hanks' solution at 37 °C. Specimens were immersed in the electrolyte during 21 days. Semi‐conducting properties of the passive film naturally formed on the surface of the metallic material during the test were evaluated through the Mott–Schottky approach. The aim was to investigate the correlation between corrosion resistance and semi‐conducting properties in the physiological solution. The corrosion resistance was found to decrease with the immersion time. The density of defects in the passive film increased accordingly as indicated by the Mott–Schottky plots. The passive film presented a semi‐conducting behavior with a duplex character. Above the flat band potential the behavior was typical of an n‐type semiconductor whilst below such value it was typical of a p‐type semiconductor. The results from EIS measurements and Mott–Schottky were in good agreement, suggesting that the corrosion resistance of biomedical stainless steels may be associated with the semi‐conducting properties of the passive films formed during immersion in physiological medium.
Corrosion–erosion wear of N80 carbon steel and 316L stainless steel in saline–quartz slurry
Authors: Li H. , Liu Y. H. , Wang Y. Z. , Ma J. M. , Cai B. P. , Ji R. J. , Zhang Y. Z.
Published: April 2011

The corrosion–erosion behavior of carbon steel N80 and austenitic stainless 316L are investigated both in water–quartz slurry and saline–quartz slurry. The sample mass losses after each test and the roughness of sample surfaces are measured and a potentiostat is used to gain the polarization curves. The worn surfaces and the corrosion–erosion wear mechanism are analyzed using scanning electron microscopy (SEM) and 3D ultra‐deep microscopy. Results show that the Ra for N80 is much larger than 316L under the same experimental condition, and the weight losses of the two materials show a similar trend except for tests with higher impact angles. The lowest Rsm for 316L matches along with the highest Rsm for N80 at the 45 min testing time. According to the obtained results of the corrosion–erosion mechanism of the N80 and 316L based on the SEM and 3D ultra‐deep microscopy, the conclusion is drawn that the ploughing and crashing are the major mechanisms for the forming of surface morphologies and the mass removal. Different impact angles and materials affect the corrosion–erosion process to some extent.
Corrosion behaviour in physiological fluids of surface films formed on titanium alloys
Authors: Rosca J. C. Mirza , Vasilescu E. , Drob P. , Vasilescu C. , Drob S. I.
Published: April 2011

The properties of the surface films formed on Ti and its Ti–5Al–4V and Ti–6Al–3.5Fe alloys by chemical (immersion in 10 M NaOH) and thermal treatment (500 °C) were studied in this paper. Their corrosion behaviour in Ringer solution was investigated. After treatments, the sample microhardness was measured. Also, the sample surfaces were observed by an optical microscope before and after immersion in Ringer solutions. The electrochemical behaviour of the surface films obtained by the chemical and thermal treatments was studied using the methods of the electrochemical impedance spectroscopy (EIS) and monitoring of open circuit potentials at different immersion periods (up to 60 days) in Ringer solution. Microhardness increased with the increasing loads for the studied materials, showing the existence of a compact protective layer. Microscopic observations exhibited more compact coatings after 60 days of exposure in Ringer solution, due to the formation of an apatite layer. EIS spectra revealed surface films with two layers: an inner, barrier protective layer and an outer, porous apatite layer. The impedance increases in time denoting that the films have grown by apatite nucleation. Also, EIS spectra showed that the complex treatment by chemical + heat method is the most efficiently. For the samples treated by the two processes (chemical + heat) the values of the open circuit potentials are nobler than of the chemical treated samples, denoting better protective, bioactive films.
Fully coupled simulation of fluid injection into geomaterials with focus on nonlinear near‐well behavior
Authors: Preisig Matthias , Prévost Jean H.
Published: April 2011

An important part of our global wealth depends on the extraction of fluids from porous media. More recently, sequestration of carbon dioxide (rmCO2) into deep geological layers as a possible measure to mitigate climate change has increased interest in fluid injection into porous media. Sophisticated numerical models play an important role in managing the uncertainties related to the subsurface, and finite element methods are the most versatile tool allowing the coupling of fluid flow, geomechanics and other physical processes. This paper gives insight into two important aspects of fluid injection/extraction in porous media: the correct modeling of the bore hole through specification of initial stresses, which together with a fully coupled strategy allows simulation of nonlinear poromechanics, and the imposition of appropriate boundary conditions that allow the controlled injection/extraction of a total specified amount of fluid in an anisotropic porous medium, without exceeding a safe operating pressure. Copyright © 2011 John Wiley & Sons, Ltd.
A cost–benefit analysis of multidimensional fractionation of affinity purification‐mass spectrometry samples
Authors: Dunham Wade H. , Larsen Brett , Tate Stephen , Badillo Beatriz Gonzalez , Goudreault Marilyn , Tehami Yasmina , Kislinger Thomas , Gingras Anne‐Claude
Published: April 2011

Affinity purification coupled to mass spectrometry (AP‐MS) is gaining widespread use for the identification of protein–protein interactions. It is unclear, however, whether typical AP sample complexity is limiting for the identification of all protein components using standard one‐dimensional LC‐MS/MS. Multidimensional sample separation is useful for reducing sample complexity prior to MS analysis and increases peptide and protein coverage of complex samples. Here, we monitored the effects of upstream protein or peptide separation techniques on typical mammalian AP‐MS samples, generated by FLAG affinity purification of four baits with different biological functions and/or subcellular distribution. As a first separation step, we employed SDS‐PAGE, strong cation exchange LC, or reversed‐phase LC at basic pH. We also analyzed the benefits of using an instrument with a faster scan rate, the new TripleTOF 5600 mass spectrometer. While all multidimensional approaches yielded a clear increase in spectral counts, the increase in unique peptides and additional protein identification was modest and came at the cost of increased instrument and handling time. The use of a high duty‐cycle instrument achieved similar benefits without these drawbacks. An increase in spectral counts is beneficial when data analysis methods relying on spectral counts, including Significance Analysis of INTeractome (SAINT), are used.
Proteomic analysis of papaya (Carica papaya L.) displaying typical sticky disease symptoms
Authors: Rodrigues Silas P. , Ventura José A. , Aguilar Clemente , Nakayasu Ernesto S. , Almeida Igor C. , Fernandes Patricia M. B. , Zingali Russolina B.
Published: April 2011

Papaya (Carica papaya L.) hosts the only described laticifer‐infecting virus (Papaya meleira virus, PMeV), which is the causal agent of papaya sticky disease. To understand the systemic effects of PMeV in papaya, we conducted a comprehensive proteomic analysis of leaf samples from healthy and diseased plants grown under field conditions. First, a reference 2‐DE map was established for proteins from healthy samples. A total of 486 reproducible spots were identified, and MALDI‐TOF‐MS/MS data identified 275 proteins accounting for 159 distinct proteins from 231 spots that were annotated. Second, the differential expression of proteins from healthy and diseased leaves was determined through parallel experiments, using 2‐DE and DIGE followed by MALDI‐TOF‐MS/MS and LC‐IonTrap‐MS/MS, respectively. Conventional 2‐DE analysis revealed 75 differentially expressed proteins. Of those, 48 proteins were identified, with 26 being upregulated (U) and 22 downregulated (D). In general, metabolism‐related proteins were downregulated, and stress‐responsive proteins were upregulated. This expression pattern was corroborated by the results of the DIGE analysis, which identified 79 differentially expressed proteins, with 23 identified (17 U and 6 D). Calreticulin and the proteasome subunits 20S and RPT5a were shown to be upregulated during infection by both 2‐DE and DIGE analyses. These data may help shed light on plant responses against stresses and viral infections.
Melting curve of the cI16 sodium at high pressure from ab initio calculations
Authors: Zhou Dawei , Bao Gang , Jin Xilian , Liu Bingbing , Cui Tian
Published: April 2011

The melting curve of cI16 sodium at high pressure is investigated extensively by means of Lindemann melting criterion and ab initio molecular dynamics simulations. Different from previous theoretical results, our results show that the melting point of cI16 sodium decreases with increasing pressure. It is found that the elastic constant softening plays an important role and results in a negative‐slope Lindemann melting curve of cI16 sodium. The melting mechanism is different from that of f.c.c. sodium reported in previous work, that the Peierls‐like liquid transition is the origin of negative‐slope melting curve. Electronic structure analysis shows that more electrons in liquid sodium localize in the voids of lattice just like in its solid state, the exclusionary effect of atomic cores on valence electrons in the liquid still takes effect.
Development of an enantiomer‐specific stable carbon isotope analysis (ESIA) method for assessing the fate of α‐hexachlorocyclo‐hexane in the environment
Authors: Badea Silviu‐Laurentiu , Vogt Carsten , Gehre Matthias , Fischer Anko , Danet Andrei‐Florin , Richnow Hans‐Hermann
Published: April 2011

α‐Hexachlorocyclohexane (α‐HCH) is the only chiral isomer of the eight 1,2,3,4,5,6‐HCHs and we have developed an enantiomer‐specific stable carbon isotope analysis (ESIA) method for the evaluation of its fate in the environment. The carbon isotope ratios of the α‐HCH enantiomers were determined for a commercially available α‐HCH sample using a gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS) system equipped with a chiral column. The GC‐C‐IRMS measurements revealed δ‐values of −32.5 ± 0.8‰ and −32.3 ± 0.5‰ for (−) α‐HCH and (+) α‐HCH, respectively. The isotope ratio of bulk α‐HCH was estimated to be −32.4 ± 0.6‰ which was in accordance with the δ‐values obtained by GC‐C‐IRMS (−32.7 ± 0.2‰) and elemental analyzer‐isotope ratio mass spectrometry (EA‐IRMS) of the bulk α‐HCH (−32.1 ± 0.1‰). The similarity of the isotope ratio measurements of bulk α‐HCH by EA‐IRMS and GC‐C‐IRMS indicates the accuracy of the chiral GC‐C‐IRMS method. The linearity of the α‐HCH ESIA method shows that carbon isotope ratios can be obtained for a signal size above 100 mV. The ESIA measurements exhibited standard deviations (2σ) that were mostly < ± 0.5‰. In order to test the chiral GC‐C‐IRMS method, the isotope compositions of individual enantiomers in biodegradation experiments of α‐HCH with Clostridium pasteurianum and samples from a contaminated field site were determined. The isotopic compositions of the α‐HCH enantiomers show a range of enantiomeric and isotope patterns, suggesting that enantiomeric and isotope fractionation can serve as an indicator for biodegradation and source characterization of α‐HCH in the environment. Copyright © 2011 John Wiley & Sons, Ltd.
Application of capillary isoelectric focusing and peptide mass fingerprinting in carbohydrate‐deficient transferrin detection
Authors: Luo Lian‐Zhong , Jin Hong‐Wei , Huang He‐Qing
Published: April 2011

Carbohydrate‐deficient transferrin (CDT) is a specific biomarker of alcohol abuse and is widely used in clinical diagnosis to detect and follow up excessive alcohol consumption. However, false %CDT results still exist in CDT detection, because of interference from genetic variants and the lack of standardization in CDT analysis. Therefore, it is still very important to find a method with high sensitivity and high accuracy for CDT detection. Here, we compared the detection sensitivity and accuracy of pI values based methods [isoelectric focusing on polyacrylamide gel electrophoresis (IEF‐PAGE) and capillary isoelectric focusing (CIEF)] with hydrophobic characteristic based methods [reversed‐phase high‐performance liquid chromatography (RP‐HPLC)] on CDT detection. Moreover, we investigated the potential of peptide mass fingerprinting (PMF), a method based on the mass spectrometry to identify human transferrin (HTf) variants including CDT isoforms and genetic variants, based on their specific peptide masses. Results indicated that PMF can identify HTf variants including CDT isoforms and genetic variants based on their specific peptides, and CIEF showed higher sensitivity detection of HTf variants than RP‐HPLC and IEF‐PAGE did. Accordingly, we suggest that PMF is suitable for identifying CDT with high accuracy, and CIEF has potential for detection of CDT and genetic variants with high sensitivity; moreover, they are both worth further investigatation in clinical diagnosis. Copyright © 2011 John Wiley & Sons, Ltd.
An experimental approach to enhance precursor ion fragmentation for metabolite identification studies: application of dual collision cells in an orbital trap
Authors: Bushee Jennifer L. , Argikar Upendra A.
Published: April 2011

Recent advancements in mass spectrometry including data‐dependent scanning and high‐resolution mass spectrometry have aided metabolite profiling for non‐radiolabeled xenobiotics. However, narrowing down a site of metabolism is often limited by the quality of the collision‐induced dissociation (CID)‐based precursor ion fragmentation. An alternative dissociation technique, higher energy collisional dissociation (HCD), enriches compound fragmentation and yields ‘triple‐quadrupole‐like fragmentation’. Applying HCD along with CID and data‐dependent scanning could enhance structural elucidation for small molecules. Liquid chromatography/multi‐stage mass spectrometry (LC/MSn) experiments with CID and HCD fragmentation were carried out for commercially available compounds on a hybrid linear ion trap orbital trap mass spectrometer equipped with accurate mass measurement capability. The developed method included stepped normalized collision energy (SNCE) parameters to enhance MS fragmentation without tuning for individual compounds. All the evaluated compounds demonstrated improved fragmentation under HCD as compared with CID. The results suggest that an LC/MSn method that incorporated both SNCE HCD‐ and CID‐enabled precursor ion fragmentation afforded comprehensive structural information for the compounds under investigation. A dual collision cell approach was remarkably better than one with only CID MSn in an orbital trap. It is evident that such an acquisition method can augment the identification of unknown metabolites in drug discovery by improving fragmentation efficiency of both the parent compound and its putative metabolite(s). Copyright © 2011 John Wiley & Sons, Ltd.
Characterization of cyanide‐trapped methylated metabonates formed during reactive drug metabolite screening in vitro
Authors: Rousu Timo , Tolonen Ari
Published: April 2011

Reactive metabolites are estimated to be one of the main reasons behind unexpected drug‐induced toxicity, by binding covalently to cell proteins or DNA. Due to their high reactivity and short lifespan, reactive metabolites are analyzed after chemical trapping with nucleophilic agents such as glutathione or cyanide. Recently, unexplained and uncharacterized methylated reaction products were reported in a human liver microsome based reactive metabolite trapping assay utilizing potassium cyanide as a trapping agent. Here, a similar assay was utilized to produce mono‐ or dimethylated and further cyanide‐trapped reaction products from propranolol, amlodipine and ciprofloxacin, followed by ultra‐performance liquid chromatography/time‐of‐flight mass spectrometry (UPLC/TOF‐MS) and ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) experiments for their more detailed structural elucidation. Formation of all observed cyanide‐trapped products was clearly NADPH‐dependent and thus metabolism‐mediated. The suggested reaction pathways included N‐methylation leading to iminium formation in primary and/or secondary amines preceded by cytochrome P450 (CYP)‐mediated reactions. As the methylation reaction was suggested to be involved in formation of the actual reactive iminium ion, the observed cyanide‐trapped products were experimental artifacts rather than trapped reactive metabolites. The results stress that to avoid overestimating the formation of reactive metabolites in vitro, this methylation phenomenon should be taken into account when interpreting the results of cyanide‐utilizing reactive metabolite trapping assays. This in turn emphasizes the importance of identification of the observed cyano conjugates during such studies. Yet, metabolite identification has a high importance to avoid overestimation of in vitro metabolic clearance in the cases where this kind of metabonate formation has a high impact in the disappearance rate of the compound. Copyright © 2011 John Wiley & Sons, Ltd.
Rapid characterization of protein productivity and production stability of CHO cells by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Feng Hua‐tao , Sim Lyn Chiin , Wan Corrine , Wong Niki S. C. , Yang Yuansheng
Published: April 2011

The biopharmaceutical industry has been in pursuit of strategies which can isolate stable and high‐producing cell lines. The whole cell mass spectrometry method by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) is a rapid and simple method for cell characterization based on the differences in the fingerprints of the mass spectra. This work describes how the method was evaluated for the application of screening for stable and high‐producing clones from a panel of recombinant Chinese hamster ovary (CHO) cell lines. Detectable m/z values and their relative intensities were collected and processed by partial least squares (PLS). To reduce the errors introduced by the preparation method and spectra noise, high intensity preliminary data was selected and the number of variables introduced was validated by leave‐one‐out cross‐validation. The differences in recombinant protein productivity and titer were revealed by PLS regression with promising results. Partial least‐squares discriminant analysis (PLS‐DA) was applied to differentiate stable and unstable cell lines as traditional stability testing would require several months involving numerous continuous passages. Results confirmed that the whole cell MALDI‐TOF method can be a powerful method for routine monitoring of bioprocesses and study can be further developed by extending the number of the cell lines tested to establish a recombinant cell line database. Copyright © 2011 John Wiley & Sons, Ltd.
Facility monitoring of chemical warfare agent simulants in air using an automated, field‐deployable, miniature mass spectrometer
Authors: Smith Jonell N. , Noll Robert J. , Cooks R. Graham
Published: April 2011

Vapors of four chemical warfare agent (CWA) stimulants, 2‐chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field‐deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual‐tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components. Copyright © 2011 John Wiley & Sons, Ltd.
Thermoplastic starch modified with hydrophobic polyurethane microparticles
Authors: Wu Qiangxian , Zhang Pingping , Zhang Yu , Fan Bingbing , Zhu Mei , Wu Zhengshun
Published: April 2011

Modified thermoplastic starches (TPS) were successfully prepared from corn starch (CS) and hydrophobic polyurethane prepolymers (PUPs) by solid‐state reactions under intensive mixing conditions. The structure and properties were investigated using FTIR, SEM, wide‐angle XRD, tensile testing machine, Brookfield viscometer, and contact angle (CA) meter. The results showed that 98.6 ± 0.4% of PUP was cross‐linked to starch, suggesting a high efficiency of the solid‐state reaction. Compared with unmodified starch, the hydrophobic property of the modified TPS was improved, resulting in an increase of the CAs and a decrease of the Brookfield viscosity. Morphology analysis indicated that the modified starch exhibited increased compatibility between the PUP particle and nature starch, leading to the increased elongation at break.
Effects of water requirement and substitution level on wheat–rice noodles with hydrocolloids
Authors: Suwannaporn Prisana , Wiwattanawanich Kamonphan
Published: April 2011

Substitution of wheat flour with rice flour in noodles can increase rice flour utilization, reduce cost, and lower the allergenicity of wheat gluten. High‐AM rice flour (32.5%) was used to dilute high‐protein wheat flour (14.8%) on account of its excellent gel‐forming properties. Target noodles should obtain qualities comparable to noodles made from all‐purpose wheat flour (10.4% protein). RSM technique was applied for optimization of substitution level, water requirement and hydrocolloid level. The coefficient of determination (R2) showed that only substitution level and water requirement could predict textural characteristics and lightness (L*) of cooked noodles. Increased amounts of rice flour resulted in a decrease in all cooked noodle textural qualities but an increase inL*. Water absorption of rice flour was significantly higher than that of wheat flour; therefore, increased water content of substituted wheat noodles was necessary. However, water requirement should correspond well with rice substitution level. CMC was observed to be more appropriate for use in wheat–rice noodles. Wheat–rice noodles were not significantly different from wheat noodles at 30–47% substitution, water requirement 43.5–59%, and 1.2–1.5% CMC. The addition of 1.5% Na2CO3resulted in a significant improvement in cooked wheat–rice noodle texture (p ≤ 0.05).
Crystal Structure, Synthesis, and Properties of tri‐Calcium di‐Citrate tetra‐Hydrate [Ca3(C6H5O7)2(H2O)2]·2H2O
Authors: Herdtweck Eberhardt , Kornprobst Tobias , Sieber Roland , Straver Leo , Plank Johann
Published: April 2011

From hydrothermal synthesis needle‐shaped crystals of [Ca3(C6H5O7)2(H2O)2]·2H2O were obtained. The crystal structure was determined by single‐crystal X‐ray experiments and confirmed by powder data (P$\bar{1}$ (no. 2) a = 5.9466(4), b = 10.2247(8), c = 16.6496(13) Å, α = 72.213(7)°, β = 79.718(7)°, γ = 89.791(6)°, V = 947.06(13) Å3, Z = 2, R1 = 0.0426, wR2 = 0.1037). The structure was obtained from pseudo merohedrically polysynthetic twinned crystals using a combined data collection approach and refinement processes. The observed three‐dimensional network is dominated by eightfold coordinated Ca2+ cations linked by citrate anions and hydrogen bonds between two non‐coordinating crystal water molecules and two coordinating water molecules.
Case study: training a chimpanzee (Pan troglodytes) to use a nebulizer to aid the treatment of airsacculitis
Authors: Gresswell Claire , Goodman Gidona
Published: April 2011

Bacterial airsacculitis has been reported in a variety of nonhuman primates, and is widely treated using a combination of surgery and oral antibiotics. This case study details an alternative method of administering antibiotics (via the use of a nebulizer) when the chimpanzee subject developed resistance to all available oral preparations. Training the chimpanzee to use the nebulizer was performed using positive reinforcement techniques (PRT). It took a total of 89 sessions (<7 hr 25 min) to train the chimpanzee to use the nebulizer. The airsacculitis infection was treated using colistin in the nebulizer twice a day for 9 days. Out of 18 potential treatment sessions, full doses were administered on 13 occasions. The final dose of colistin was given via slow brachial intravenous injection under general anesthesia. The infection was successfully treated with colistin. Although there was a training time investment involved, it was felt to be outweighed by the success of the treatment. Also in the likelihood of the infection re‐occurring at a later date, the now learnt behavior of using a nebulizer means that future treatment should now be considerably quicker. This is another example of how PRT is a useful tool in the successful welfare and management of captive animals. Zoo Biol 30:570–578, 2011. © 2011 Wiley Periodicals, Inc.
Extreme Values of Maternal Serum Analytes in Second Trimester Screening: Looking Beyond Trisomy and NTD's
Authors: McPherson Elizabeth , Thomas Ginger D. , Manlick Christopher , Zaleski Christina A. , Reynolds Kara K. , Rasmussen Kristen , Giampietro Philip F. , Wiley Carmen , Mascola Maria
Published: April 2011

Second trimester maternal serum screening can identify high risk pregnancies and fetuses at risk for birth defects (in addition to those in the standard interpretation). The purpose of this study was to quantify such risks to improve counseling. We compared outcomes of 692 pregnancies that had abnormal levels of at least one analyte with a cohort of 713 pregnancies with normal analytes. Increased risks include: demise with high AFP and low uE3; intrauterine growth restriction with high AFP, high and low hCG, and low uE3; placental abnormalities with high AFP; fetal stress with high AFP and high hCG. Birth defects are increased with high AFP, high hCG, and low hCG. When two or more analytes are abnormal, 46% have a poor outcome. Abnormal levels of maternal serum analytes provide information in addition to the risks for neural tube defects, Down syndrome, and trisomy 18. This information is important for counseling and pregnancy management.
Beyond Russia, Becoming Local: Trajectories of Adaption to the Fall of the Soviet Union among Ethnic Russians in the Former Soviet Republics
Authors: Kolstø Pål
Published: April 2011

When the Soviet Union began to unravel in the late 1980s, many observers expected that the 25 million ethnic Russians who lived in the non-Russian republics represented an important group of people who could be mobilized by ‘empire-savers’ to stem this process. Russians who would end up as minorities in new nationalizing states, had little if anything to gain from state disintegration. They were also highly resourceful in terms of education and occupational positions. The sinister role which ethnic Serbs played in Slobodan Milosevic's schemes to salvage the Yugoslav state boded ill, as did the bloody war waged by France in Algeria in protection of the pied-noirs in the 1950s.

As it turned out, the Russians in the non-Russian republics for the most part remained remarkably passive, and this contributed in no small degree to the tranquil transition to a new political map in Eurasia. This article is an attempt to explain this counterintuitive outcome. I revisit a typology of identity trajectories for the Russian diaspora which I developed in the mid-1990s and conclude that its basic insights remain valid. At that time I had argued that Russians outside the RSFSR had already for some time been going through a process of dissociation from the Russian core group. They were adopting some cultural traits from the local population without undergoing any kind of assimilation. While there were important regional varieties as well as generational differences within each Russophone community, as a general rule it could be said that they had developed an identity of their own, or more precisely: one local identity for each republic. In this way Russian ethnic solidarity was weakened and the mobilizational potential of the diaspora issue for political purposes was diminished.

Empirical research carried out by myself and others over the last 15 years, including large-scale opinion polls, seem to confirm these assumptions. After the break-up of the unitary state the distance between the identity trajectories of the various Russian-speaking post-Soviet communities have gradually grown wider, for a number of reasons. Those Russians who were least willing or able to adapt to the new political circumstances have in many cases returned to Russia, making it even more important for those who remain to learn the local language and find their cultural-political niche in their country of residence as a national minority.