bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supersonic gas chromatography/mass spectrometry
Authors: Amirav Aviv , Gordin Alexander , Tzanani Nitzan 
Published: August 2002

AbstractA new gas chromatography/mass spectrometry (GC/MS) system was designed and evaluated which we have named ‘Supersonic GC/MS’. It is based on a modification of a commercially available GC/MS system to include a supersonic molecular beam (SMB) MS interface. In this system the standard electron ionization (EI) ion source was replaced with a fly‐through EI ion source mounted in the path of the SMB. A hyperthermal surface ionization (HSI) ion source combined with a 90 ° ion mirror (for the EI‐produced ions) was also added, and placed inside the quadrupole mass analyzer in place of its original EI ion source. The ‘Supersonic GC/MS’ system requires 18 cm added bench space plus the addition of an air‐cooled 60 L/s diffusion pump and a 537 L/min rotary pump. The system is user friendly since all the gas flow rates, heated zones, sampling and data analysis are performed the same way as the original system and are computer‐controlled via the original software. Similar EI sensitivity was obtained as with the original system for hexachlorobenzene and octafluoronaphthalene, while improved EI detection limits were demonstrated for methyl stearate and eicosane due to the significant enhancement of their molecular ion abundances. A GC/MS detection limit of 500 ag for pyrene was demonstrated using HSI. Good supersonic expansion cooling was achieved with large alkanes, despite the use of a rotary pump at the nozzle chamber instead of a diffusion pump. High temperature GC/MS analysis was demonstrated for large polycyclic aromatic hydrocarbons (PAHs) including ovalene and decacyclene (ten rings). Library searches with EI mass spectra are demonstrated, and it is explained why the enhancement of the molecular ion actually improves the library search in most cases. The analysis of large phthalate esters is also described, and the improvement obtained is shown to originate from their enhanced molecular and high mass fragment ions. Copyright © 2001 John Wiley & Sons, Ltd.
Estimation of proton affinity of proline and tryptophan under electrospray ionization conditions using the extended kinetic method
Authors: Mirza Shama P. , Prabhakar S. , Vairamani M. 
Published: August 2002

AbstractThe relative order of the proton affinity (PA) of 20 naturally occurring amino acids has been determined under electrospray ionization conditions and compared with earlier studies of different research workers. The order we obtained is similar to that reported by other groups except in three cases viz., valine–aspartic acid, asparagine–glutamic acid and tryptophan–proline. The PA values of proline and tryptophan are determined by the extended kinetic method using amino acids themselves as reference bases. The PA values we thus obtained for proline and tryptophan are 219.9 and 221.6 kcal/mol, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Investigation of synthetic peptide hormones by liquid chromatography coupled to pneumatically assisted electrospray ionization mass spectrometry: analysis of a synthesis crude of peptide triptorelin
Authors: Sanz‐Nebot V. , Toro I. , Castillo A. , Barbosa J. 
Published: August 2002

AbstractTriptorelin, a synthetic peptide hormone used in the treatment of prostate cancer by means of reduction in the action of male hormone testosterone, is studied here. The synthetic procedure commonly results in unwanted side products that require extensive purification and characterization of the synthesis mixture. The chromatographic separation of triptorelin from the crude mixture was developed by applying the linear solvation energy relationship (LSER) methodology previously developed, to optimize the composition of the mobile phase in order to avoid lengthy empirical optimization procedures. Electrospray ionization mass spectrometry coupled to liquid chromatography (LC/ES‐MS) was used to obtain reliable information on the inevitable side products. The knowledge of the identity of these impurities allows fast optimization of the synthetic procedure and also the therapeutic use of triptorelin peptide hormone. Copyright © 2001 John Wiley & Sons, Ltd.
Practical aspects of liquid chromatography/electrospray tandem mass spectrometry for rapid identification of metabolites of a new antifungal agent SYN‐2836 in dog urine
Authors: Bu Hai‐Zhi , Poglod Marzena , Micetich Ronald G. , Khan Jehangir K. 
Published: August 2002

AbstractThis report presents the structural elucidation of 12 urinary metabolites of SYN‐2836, a new antifungal agent showing extensive metabolism in beagle dogs, using complementary liquid chromatography/tandem mass spectrometry (LC/MS/MS) methodologies. The 12 SYN‐2836 metabolites were readily divided into four groups by considering that all three members of each group, although differing in masses, exhibited highly similar product ion mass spectra. This suggests that the metabolites within each group share a common major substructure. Therefore, all the grouped SYN‐2836 metabolites were strategically identified by characterization of the major substructures followed by determination of the additional small substructures. This grouping strategy greatly facilitated the structural elucidation of these metabolites. Other strategies were also employed to achieve as rapid and unambiguous characterization of the SYN‐2836 metabolites as possible. Copyright © 2001 John Wiley & Sons, Ltd.
An investigation of cobalt oxide based nanocrystalline thin films by secondary ion mass spectrometry
Authors: Barison Simona , Barreca Davide , Daolio Sergio , Fabrizio Monica , Tondello Eugenio 
Published: August 2002

AbstractAn investigation of cobalt oxide based nanocrystalline thin films by secondary ion mass spectrometry (SIMS) is presented. The coatings, whose composition ranged between CoO and Co3O4, were synthesized by chemical vapor deposition (CVD) on indium tin oxide (ITO) substrates, using cobalt(II) β‐diketonate as precursor. The SIMS analysis revealed a satisfactory precursor conversion into the oxides and allowed distinction of regions in the films at different compositions. Film‐substrate intermixing phenomena were evidenced and studied as a function of deposition temperature, film thickness and composition. Copyright © 2001 John Wiley & Sons, Ltd.
Electrospray ionization mass spectrometric study of the hydrolysis‐polycondensation process of Sn(OBut)4
Authors: Armelao Lidia , Schiavon Giovanni , Seraglia Roberta , Tondello Eugenio , Russo Umberto , Traldi Pietro 
Published: August 2002

AbstractThe oligomerization of Sn(OBut)4 in the sol‐gel process has been studied by several different analytical approaches. Electrospray ionization (ESI) mass spectrometry was highly effective in describing the first species produced by the hydrolysis‐polycondensation reactions. Mössbauer spectroscopy has elucidated the fast behavior of the hydrolytic oligomerization process, while calorimetric data have demonstrated the high enthalpy of the reaction in the presence of different solvents. Copyright © 2001 John Wiley & Sons, Ltd.
Mass spectral study of O‐ and S‐aryl dimethylthiocarbamates under electron impact conditions: Newman‐Kwart rearrangement in the gas phase
Authors: Prabhakar S. , Kar Paramita , Mirza S. P. , Lakshmi V. V. S. , Nagaiah K. , Vairamani M. 
Published: August 2002

AbstractThe electron impact (EI) mass spectra of isomeric S‐ and O‐aryl (2‐naphthyl, R‐Ph‐ = aryl, where R = H, NO2, COOCH3, COCH3 and OCH3) dimethylthiocarbamates have been studied in detail. The EI spectra of O‐aryl dimethylthiocarbamates include some of the fragment ions that are characteristic of the corresponding S‐aryl isomer, which could be explained by a Newman‐Kwart rearrangement in the ion source of the mass spectrometer, after ionization. The EI mass spectra of S‐aryl dimethylthiocarbamates showed specific fragment ions resulting from cleavage of the molecular ion involving the bond between sulfur and the carbonyl group of the carbamate moiety (α‐cleavage). The EI mass spectra of O‐aryl dimethylthiocarbamates, however, showed the fragmentation of the molecular ion by α‐cleavage involving the bonds on both sides of oxygen atom. Further, the EI mass spectra of O‐aryl dimethylthiocarbamates containing an electron‐withdrawing substituent (‐R) on the aryl group showed a characteristic fragment ion corresponding to [M − R]+. Copyright © 2001 John Wiley & Sons, Ltd.
Structural elucidation of dicarboxylated metabolites of nonylphenol polyethoxylate surfactants in surface waters by gas chromatography/tandem mass spectrometry
Authors: Ding Wang‐Hsien , Wu Chien‐Yi 
Published: August 2002

AbstractPersistent dicarboxylated metabolites of nonylphenol polyethoxylates (NPEOs), carboxyalkylphenoxy ethoxy carboxylates (CAPECs), have periodically been detected during gas chromatography/mass spectrometry (GC/MS) characterization of NPEO metabolites in samples of surface water and sewage effluent. An electron impact ionization (EI) MS study was conducted on two esterified CAPEC metabolites, CA4P1EC isomers (where A4 denotes a 4‐carbonalkyl group plus one carboxylic group (C)). The most abundant characteristic ions were produced by benzylic cleavages to yield [M−87]+ and [M−101]+ ions, corresponding to ions of m/z 249 and 235, each of which is formed from one of two isomeric dipropyl esters CA4P1EC. These two base‐peak ions were selected as precursor ions to help elucidate the fragmentation mechanisms and support the proposed structures via tandem mass spectrometric (MS/MS) experiments. The two isomers have been tentatively identified as 4‐(2‐ethyl‐2‐methylacetic acid)phenoxyacetic acid and 4‐(3,3‐dimethylpropionic acid)phenoxy acetic acid, which give rise to the fragments at m/z 249 and 235, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Liquid chromatography/electrospray ionisation mass spectrometric investigations of imidazoline corrosion inhibitors in crude oils
Authors: McCormack P. , Jones P. , Rowland S. J. 
Published: August 2002

AbstractThe so‐called imidazolines (2‐alkyl‐1‐[ethylalkylamide]‐2‐imidazolines and 2‐alkyl‐1‐ethylamine‐2‐imidazolines) are a group of surface‐active compounds, complex mixtures of which are used by various industries as surfactants and corrosion inhibitors. Although their industrial synthesis was reported over 100 years ago, few methods for the determination of individual imidazolines in mixtures, including industrial matrices such as crude oils, have been reported. Here we demonstrate that spiking of crude oils with synthetic imidazolines followed by solid‐phase extraction and liquid chromatography/electrospray ionisation multistage mass spectrometry (LC/ESI − MSn) allows an estimation of low (<10) parts per million concentrations of individual imidazolines in crude oils. Whilst non‐optimised at present, the method is a significant advance and may prove useful not only for improving an understanding of the mechanisms of industrial imidazoline synthesis and for monitoring downhole and topside oilfield operations, but also for the determination of the fate of imidazoline‐based oilfield corrosion inhibitors and surfactants in the environment. Copyright © 2002 John Wiley & Sons, Ltd.
Electron ionisation mass spectral analysis and fragmentation pathways for some thiophosphorylicp‐carboxybenzene sulfonamides
Authors: Nicoarã Simona , Culea Monica 
Published: August 2002

AbstractThe work presents the 70 eV electron impact mass spectra of some thiophosphorylic p‐carboxybenzene sulfonamides, and proposes rationalisation of their fragmentation pathways. Accurate mass measurements of the fragment ions, and metastable ion analyses performed in the MIKES mode, were used to elucidate the most abundant ion compositions and to elucidate the fragmentation patterns of these pharmacologically interesting compounds. Copyright © 2002 John Wiley & Sons, Ltd.
Transpiration in Black Willow Phytoremediation Plots as Determined by the Tree‐Trunk Heat Balance Method
Authors: Conger Robert M. , Portier Ralph J. 
Published: August 2002

AbstractPlant transpiration is a critical process that affects the water balance in phytoremediation plots. The
desired effect is to remove contaminated water from the soils through the plant metabolism. Thus, the
transpiration rate can be a major component in modeling the groundwater flow and solute transport for a
phytoremediation project and ultimately can determine the time expected to achieve remedial goals. Two
phytoremediation plots of black willows (Salix nigra) were planted during October
1996 over separate,shallow groundwater plumes at a site in southeastern Louisiana. Concentrations of less than
10 mg/l of the herbicide bentazon were present in the shallow groundwater. Field experiments were developed
and performed during the 1998 and 1999 growing seasons to measure sap flow as an indicator of plant
transpiration. The tree‐trunk heat balance method was used to measure sap flow. Sap flow was indexed to
the cross‐sectional area of the stem, and the sum of the available stem area for each plot was used to
calculate the monthly water use in each plot. Daily water use in the plots averaged between 6 to 13
l/day/m2 during the periods tested in 1998 and 1999. By applying growth‐rate
observations with the daily water use, annual water use at tree plot maturity was estimated to be
3.6×106 l/year in Plot 1 and 11.39×106 l/year in Plot 2. Application
of these data will allow groundwater modeling to be performed to measure the effectiveness of phytoremediation
and to predict closure of remediation at the test site. © 2001 John Wiley & Sons, Inc.
Isotope applications in environmental investigations: Theory and use in chlorinated solvent and petroleum hydrocarbon studies
Authors: Sueker Julie K. 
Published: August 2002

AbstractIsotope applications are gaining acceptance for use in surface water and groundwater investigations,
complementing traditional geochemistry and physical hydrology techniques. Recent developments in analytical
methodologies and in the understanding of isotope dynamics now allow the use of isotopes to investigate sources
and fate of common groundwater contaminants such as chlorinated solvents and petroleum hydrocarbons. Contaminants
with unique isotopic signatures may facilitate the determination of contaminant sources in complex plumes.
Degradation of chlorinated solvents and some petroleum hydrocarbons impart unique isotopic signatures on both the
original contaminant and the degradation product or products that provide verification of degradation. Use of a
Rayleigh‐type model may allow determination of degradation extent. Coupled with models of contaminant fate
and transport, degradation extent may be useful for determining degradation rates. © 2001 John Wiley &
Sons, Inc.
Algebraic solution to forward kinematics of a 3‐DOF spherical parallel manipulator
Authors: Ji Ping , Wu Hongtao 
Published: August 2002

AbstractA three degree‐of‐freedom (3‐DOF) spherical parallel manipulator consists of two tetrahedrons (pyramids). The base tetrahedron is fixed while the moving tetrahedron is rotating at the joint apex of the two tetrahedrons. This article studies the forward kinematics to a special 3‐DOF spherical parallel manipulator, where the three apical angles of the moving tetrahedron are equal to their counterparts in the base tetrahedron, respectively. The final result of the forward kinematics to this parallel manipulator is a univariate quartic polynomial equation, which has a direct algebraic solution. In addition, a special right‐angle case of the manipulator is investigated and its forward kinematics can be obtained directly. © 2001 John Wiley & Sons, Inc.
An efficient method for inverse dynamics of kinematically defective parallel platforms
Authors: Li Jianfeng , Wang Jinsong , Liu Xinjun 
Published: August 2002

AbstractIn addition the general six‐degree‐of‐freedom parallel platforms, parallel platforms
with fewer than six DOF can also be used in the structural design of robotic manipulators. The common property
of these parallel platforms is that the motion parameters used to describe the position and orientation of the
movable platform are six, but fewer than six are independent. In their general configurations, arbitrary
six‐dimensional motion of the platform cannot be achieved by the actuators mounted on the legs, therefore
they are kinematically defective. Because of this defect, the inverse dynamic analysis method, which is
applicable to the general six‐DOF parallel platforms, cannot be directly used for the kinematically
defective parallel platforms (KDPPs). In this paper, an effective method for formulating the inverse
dynamics of KDPPs is presented. Using the proposed method, three different KDPPs are studied and their inverse
dynamic formulas are derived. © 2002 John Wiley & Sons, Inc.
Ecological rehabilitation of the Dutch part of the River Rhine with special attention to the fish
Authors: Raat Alexander J.P. 
Published: August 2002

AbstractThe River Rhine has suffered severely from pollution and stream regulation over the last two centuries. Industrial effluents and municipal wastewater have imposed pollutant loads, and major engineering works for drainage and navigation have changed the ecological condition of the river. Only during the last three decades has the rehabilitation of the river system been a topic of concern.The present fish fauna is dominated by eurytopic cyprinids. Rheophilous species have declined in numbers, and anadromous fish have become scarce or extinct.Various forms of ecological rehabilitation in the Dutch Rhine are identified: floodplain development; optimization of migration routes with emphasis on the entrance of migrating species from the sea into the river; and restoration of spawning and nursery areas.Ecological restoration of the Rhine is an international effort. The present socio‐economic functions of the river pose serious constraints on the feasibility of ecological targets. Copyright © 2001 John Wiley & Sons, Ltd.
Alternate link routing for traffic engineering in packet‐oriented ISL networks
Authors: Mohorčič Mihael , Werner Markus , Švigelj Aleš , Kandus Gorazd 
Published: August 2002

AbstractThe implementation of a satellite communication network consisting of intersatellite links provides a highly interconnected backbone in the space segment, increasing the network flexibility and reliability, while, on the other hand, introducing numerous issues related to network dimensioning, efficient resource management, adaptive routing, etc. In this paper we study two forwarding policies based on alternate link routing (ALR) and compare their performance with that of a simple forwarding policy employing shortest path routing (SPR) without options. All forwarding policies compared in this study are operating on routing tables calculated with the Dijkstra shortest path algorithm, capable of adapting to traffic load and propagation delay on the links through the appropriately selected link cost metric. Using an ISL network simulator, we demonstrate that both ALR forwarding policies can efficiently handle traffic load sharing among alternative routes, significantly reducing peak values of link load which is a central goal of ISL network dimensioning. Copyright © 2001 John Wiley & Sons, Ltd.
Integrating concept mapping and the learning cycle to teach diffusion and osmosis concepts to high school biology students
Authors: Odom Arthur L. , Kelly Paul V. 
Published: August 2002

AbstractThis study explores the effectiveness of concept mapping, the learning cycle, expository instruction, and a combination of conceptmapping/learning cycle in promoting conceptual understanding of diffusion and osmosis. Four high school biology classes were taught diffusion and osmosis concepts with the aforementioned treatments. Conceptual understanding was assessed immediately and seven weeks after instruction with the Diffusion and Osmosis Diagnostic Test (DODT). The results indicated the concept mapping/learning cycle and concept mapping treatment groups significantly outperformed the expository treatment group in conceptual understanding of diffusion and osmosis. There was no significant difference among the learning cycle group and other treatments. © 2001 John Wiley & Sons, Inc. Sci Ed 85:615–635, 2001.
Dynamics of saccadic eye movement depending on diurnal variation in human alertness
Authors: Ueno Akinori , Tateyama Tsuyoshi , Takase Moriichiro , Minamitani Haruyuki 
Published: August 2002

AbstractFrom the viewpoint of traffic accident prevention or intelligent interface construction, the proposal of indices which can simply evaluate alertness is desirable. In this paper, to investigate the possibility of alertness evaluation using saccadic eye movement (SC), we report 24‐hour sleep deprivation experiments and investigate the relationship between the diurnal variation and SC dynamics. It has become clear that three parameters of SC, namely, the peak velocity/duration ratio, the normalized peak velocity, and the normalized duration, have strong correlations with the amplitude component of brain waves, sleepiness, and subjective alertness. These results imply that SC dynamics have a high dependence on the two alertness indices, physiological and subjective, and the possibility of application of the SC dynamics to alertness evaluation is shown. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(7): 95–103, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1145
Surface chemistry of the iron tetraazamacrocycle on the aminopropyl‐modified surface of oxidized n‐Si(100) by AFM and XPS
Authors: Magalhães Janildo L. , Moreira Leonardo M. , Rodrigues‐Filho Ubirajara P. , Giz Martha J. , Pereira‐da‐Silva Marcelo A. , Landers Richard , Vinhas Rita C. G. , Nascente Pedro A. P. 
Published: August 2002

AbstractThe structure and formation mechanisms of 3‐aminopropyltrimethoxysilane (3‐APTS) films deposited on wet‐chemically grown silicon dioxide over n‐Si(100) wafer have been examined systematically using x‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The asymmetric N 1s XPS spectrum for the anchored 3‐APTS was fitted for –NH2 (399.6 ± 0.3 eV) and –NH3+ (401.1 ± 0.3 eV). Rougher surfaces are obtained by deposition from toluene solutions than from the gaseous phase. Over the 3‐APTS layer was deposited the [FeTIM(CH3CN)2]2+ complex, where TIM is 2,3,9,10‐tetramethyl‐1,4,8,11‐tetraazacyclotetradeca‐1,3,8,10‐tetraene. The adsorption occurs by acetonitrile replacement for the–NH2‐grafted group with the equatorial plane parallel to the organomodified surface. Once FeTIM can bind a CO, NO or N‐heterocycle, a built‐on Si wafer sensor device could be envisaged for these molecules. Copyright © 2002 John Wiley & Sons, Ltd.
Score tests for detecting excess risks around putative sources
Authors: Tango Toshiro 
Published: August 2002

AbstractFocused clustering studies examine raised disease risk around prespecified point sources. As statistical methods to detect such clusters, Stone's maximum likelihood ratio test is popular, against the general ordered alternatives and score tests which score each case the reciprocal of the distance from a point source as a surrogate exposure. This paper considers extensions of score tests in that (i) they can allow us to select the best among prespecified parametric exposure functions to avoid multiple testing problems and (ii) they can be applied to a possible situation where the hazardous substance levels have a peak at some distance from a point source. Simulation studies show that the powers of the proposed tests are higher than that of Stone's test over all the alternatives considered. The proposed tests are illustrated with hypothetical data as well as simulated data to be expected in an epidemiological study currently in progress regarding an excess risk of perinatal undesirable outcomes near municipal solid waste incinerators in Japan. Copyright © 2002 John Wiley & Sons, Ltd.