bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum
Authors: Pashynska V. A. , Kosevich M. V. , Heuvel H. Van den , Claeys M. 
Published: February 2006

AbstractThe effect of cone voltage (CV) variation on the mass spectral pattern of the bisquaternary ammonium salt decamethoxinum in the electrospray ionization (ESI) mode was studied. The advantage of decamethoxinum as a test compound in ESI mass spectrometry lies in the production of two types of precursor ions, i.e. the doubly charged organic dication Cat2+ and its singly charged cluster with a Cl− counterion, Cat · Cl+. This makes it possible to monitor the fragmentation patterns of these ions under identical experimental conditions. Pronounced qualitative and quantitative changes in the ESI mass spectra were observed upon a gradual increase of the CV. The model compound decamethoxinum allowed us to reveal the extreme situation, in which the mass spectra at a CV below and over approximately 100 V look quite different, in that they contain different product ions of Cat2+ and Cat · Cl+. While this effect may be much less pronounced for other classes of organic compounds, it should be properly taken into account for the adequate description of fragmentation pathways of bisquaternary ammonium compounds with ESI. Comparison of ESI, FAB‐SIMS and MALDI mass spectra of decamethoxinum shows that taking into account CV effects also permits us to gain information on energy deposition into ions generated with the different ionization techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Generation of regiospecific carbanions under electrospray ionisation conditions and their selectivity in ion‐molecule reactions with CO2
Authors: Kumar M. Kiran , Sateesh B. , Prabhakar S. , Sastry G. Narahari , Vairamani M. 
Published: February 2006

AbstractRegiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five different sets of positional isomers (ortho, meta and para isomers) of aromatic carboxylic acids is reported under negative electrospray ionisation conditions by decarboxylation of the carboxylate anions. The structures of decarboxylated anions, [(M–H)–CO2]−, are studied by ion‐molecule reactions with carbon dioxide in the collision cell of a triple quadrupole mass spectrometer. The [(M–H)–CO2]− ions generated from the trans and meta/para isomers react with CO2 to produce product ions corresponding to the addition of one CO2, which confirms the survival of the [(M–H)–CO2]− ions as carbanions. On the other hand, the [(M–H)–CO2]− ions generated from cis and ortho isomers failed to react with CO2 due to rapid isomerisation of the initially generated carbanion to a aromatic carboxylate/oxide anion, which is unreactive with CO2, through a facile intramolecular proton transfer from the proton‐containing substituent to the carbanion site. When the experiments were performed at high desolvation temperatures (300°C), instead of 100°C, the relative abundance of [(M–H)–CO2]− ions and the corresponding CO2 adduct in ion‐molecule reaction experiments increased significantly due to minimisation of proton exchange. Quantum chemical calculations on some of the generated isomeric carbanions and their isomerised products due to proton transfer support the selective stability of carbanions. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of curcuminoids by positive and negative electrospray ionization and tandem mass spectrometry
Authors: Jiang Hongliang , Somogyi Árpád , Jacobsen Neil E. , Timmermann Barbara N. , Gang David R. 
Published: February 2006

AbstractThe curcuminoids are a group of diarylheptanoid molecules that possess important pharmacological activities, particularly acting as anti‐inflammatory agents. The main purpose of this study was to investigate the fragmentation behavior of the three major curcuminoids in ion trap liquid chromatography/tandem mass spectrometry (LC/MS/MS). Both positive and negative mode electrospray ionization in tandem and multidimensional MSn experiments in quadrupole ion trap instruments and high‐resolution and accurate mass MS and sustained off‐resonance irradiation (SORI) MS/MS experiments in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer were used to elucidate the main fragmentation channels of these compounds. These experiments yielded essentially the same fragmentation results in both ion trap and ICR instruments for all three curcuminoids and for their phenolic monoacetates. Major and diagnostic fragment ions were identified and their origins are proposed. Copyright © 2006 John Wiley & Sons, Ltd.
The biotic and abiotic legacy of a large infrequent flood disturbance in the Sabie River, South Africa
Authors: Parsons Melissa , McLoughlin Craig A. , Rountree Mark W. , Rogers Kevin H. 
Published: February 2006

AbstractLarge infrequent disturbances (LIDs) leave heterogeneous, patchy legacies because the event may have different severities in different locations, or may influence ecosystem components differently. Biotic and abiotic legacies form the template upon which subsequent ecological processes take place and thus, LIDs can have a long‐lasting influence on ecosystems. This study determined the geomorphological (channel type), landscape state (mosaic of physical and riparian vegetation patches) and riparian vegetation legacies of an extreme flood in the Sabie River. The linear proportions of geomorphological channel types were altered by the flood because of complex patterns of sediment erosion and deposition related to bed slope and channel width. Biotic landscape states (tree, shrub, reed, herbaceous vegetation) were stripped to expose the underlying physical template. The persistence and arrangement of landscape states varied amongst channel types because of the interaction between flood flows and the geomorphological attributes of each channel type. Overall, some riparian species decreased in density because of removal by the flood, and some increased in density because of post‐flood recruitment or re‐establishment. The flood also changed the location of many species in relation to their characteristic pre‐flood elevation within the channel. In accordance with the expectations of LIDs, the effects of the flood were not uniform. Instead, the flood left a legacy of juxtaposed biotic and abiotic components that varied spatially amongst channel types and at different elevations within the channel. Copyright © 2006 John Wiley & Sons, Ltd.
Hydro‐climatic and land use changes in the River Lune catchment, North West England, implications for catchment management
Authors: Orr H. G. , Carling P. A. 
Published: February 2006

AbstractReported trends across the British Isles, illustrate changing rainfall gradients. Northern areas have become wetter in recent decades with greater variation between NW and SE rainfall totals. This paper explores hydro‐climatic changes in North‐West England over the last 140 years as part of a whole catchment investigation into the nature and causes of change in fluvial geomorphology. Variability in runoff in the Lune catchment is explained in terms of observed climate and land use changes; implications for river and catchment management are discussed.Area average annual rainfall in the North‐West of England show no clear trend over the last 100 years although rain gauges at higher altitudes appear to show increased totals. Over the last 30 years changes in the seasonality of rainfall have been observed. A greater proportion of annual rainfall has occurred in the winter half‐year and an increased frequency of wet‐days has been linked to catchment‐scale flooding. More rain falling on upland areas (> 300 m) has resulted in more rapid runoff from these areas enhanced by land use practices—specifically in heavily grazed hills with a short vegetation cover. The result is a highly varied runoff response within the catchment with localized increases in stream power and the potential for geomorphic change. This effect is ‘damped’ lower down the catchment highlighting the importance of within catchment variability and the need to conduct hydrological analysis at smaller than whole catchment scales. These findings have important implications for water resources, in particular: water storage within catchments; changes in the duration and frequency of floods and droughts; mobilization of sediment; erosion; channel and flood risk management; and ecological function. Copyright © 2006 John Wiley & Sons, Ltd.
Predicting case numbers during infectious disease outbreaks when some cases are undiagnosed
Authors: Glass K. , Becker N. , Clements M. 
Published: February 2006

AbstractWe describe a method for calculating 95 per cent bounds for the current number of hidden cases and the future number of diagnosed cases during an outbreak of an infectious disease. A Bayesian Markov chain Monte Carlo approach is used to fit a model of infectious disease transmission that takes account of undiagnosed cases. Assessing this method on simulated data, we find that it provides conservative 95 per cent bounds for the number of undiagnosed cases and future case numbers, and that these bounds are robust to modifications in the assumptions generating the simulated data. Moreover, the method provides a good estimate of the initial reproduction number, and the reproduction number in the latter stages of the outbreak. Applying the approach to SARS data from Hong Kong, Singapore, Taiwan and Canada, the bounds on future diagnosed cases are found to be reliable, and the bounds on hidden cases suggests that there were few hidden cases remaining at the end of the outbreaks in each region. We estimate that the initial reproduction numbers lay between 1.5 and 3, and the reproduction numbers in the later stages of the outbreak lay between 0.36 and 0.6. Copyright © 2006 John Wiley & Sons, Ltd.
Dramatic Effect of Dispersed Carbon Nanotubes on the Mechanical and Electroconductive Properties of Polymers Derived from Ionic Liquids
Authors: Fukushima Takanori , Kosaka Atsuko , Yamamoto Yohei , Aimiya Takuji , Notazawa Shunsuke , Takigawa Toshikazu , Inabe Tamotsu , Aida Takuzo 
Published: February 2006

AbstractFree‐radical polymerization of an imidazolium ion‐based ionic liquid bearing a methacrylate group, gelling with single‐walled carbon nanotubes (SWNTs), allows fabrication of a mechanically reinforced, electroconductive soft material (bucky plastic). A film sample of this material displays an excellent conductivity of 1 S cm−1 and a 120‐fold enhancement of the Young’s modulus at a 7 wt % content of SWNTs. The conductivity is temperature‐dependent in the range 5–300 K, suggesting that the conductive process involves carrier hopping. Scanning electron and atomic force micrographs of a bucky plastic film display the presence of crosslinked networks consisting of finely dispersed SWNTs. Such nanotube networks, developed in the polymer matrix, likely suppress slipping of entrapped polymer molecules via a strong interfacial interaction and also facilitate intertubular carrier transport. Although a bucky plastic derived from a vinylimidazolium ion‐based ionic liquid monomer shows a comparable conductivity to that of the methacrylate version, the film is brittle irrespective of the presence or absence of SWNTs.
Knowledge, abilities, cognitive characteristics and behavioral competences of engineers with high capacity for engineering systems thinking (CEST)
Authors: Frank Moti 
Published: February 2006

AbstractA major high‐order thinking skill that enables engineers to successfully perform systems engineering tasks is Engineering Systems Thinking. To successfully perform their tasks, systems engineers need a systems view or, in other words, a high capacity for engineering systems thinking (CEST). This paper summarizes the findings of three studies aimed at identifying the knowledge, abilities, cognitive characteristics (thinking skills) and personal traits (behavioral competences) of systems engineers with high capacity for engineering systems thinking (or, in other words, successful systems engineers). The findings suggest that successful systems engineers possess interdisciplinary knowledge. They are expert in at least one main field but have general knowledge in additional fields and disciplines. They become familiar with the jargon and professional language of the other disciplines and are able to communicate with people or experts from different fields and disciplines. Overall, 10 cognitive characteristics, 11 abilities, and 10 behavioral competences were identified. In addition, nine additional roles of systems engineering were identified. © 2006 Wiley Periodicals, Inc. Syst Eng 9: 91–103, 2006
Minimax D-Optimal Designs for Item Response Theory Models
Authors: Berger Martijn P. F. , Joy King C. Y. , Wong Weng Kee 
Published: February 2006

Various different item response theory (IRT) models can be used in educational and psychological measurement to analyze test data. One of the major drawbacks of these models is that efficient parameter estimation can only be achieved with very large data sets. Therefore, it is often worthwhile to search for designs of the test data that in some way will optimize the parameter estimates. The results from the statistical theory on optimal design can be applied for efficient estimation of the parameters.A major problem in finding an optimal design for IRT models is that the designs are only optimal for a given set of parameters, that is, they are locally optimal. Locally optimal designs can be constructed with a sequential design procedure. In this paper minimax designs are proposed for IRT models to overcome the problem of local optimality. Minimax designs are compared to sequentially constructed designs for the two parameter logistic model and the results show that minimax design can be nearly as efficient as sequentially constructed designs.
Item Bias Detection using Loglinear IRT
Authors: Kelderman Henk 
Published: February 2006

A method is proposed for the detection of item bias with respect to observed or unobserved subgroups. The method uses quasi-loglinear models for the incomplete subgroup × test score × Item 1 × ... × item k contingency table. If subgroup membership is unknown the models are Haberman's incomplete-latent-class models.The (conditional) Rasch model is formulated as a quasi-loglinear model. The parameters in this loglinear model, that correspond to the main effects of the item responses, are the conditional estimates of the parameters in the Rasch model. Item bias can then be tested by comparing the quasi-loglinear-Rasch model with models that contain parameters for the interaction of item responses and the subgroups.
Correspondence Analysis and Association Models Constrained by a Conditional Independence Graph
Authors: de Falguerolles Antoine , Jmel Said , Whittaker Joe 
Published: February 2006

The manner in which the conditional independence graph of a multiway contingency table effects the fitting and interpretation of the Goodman association model (RC) and of correspondence analysis (CA) is considered.Estimation of the row and column scores is presented in this context by developing a unified framework that includes both models. Incorporation of the conditional independence constraints inherent in the graph may lead to equal or additive scores for the corresponding marginal tables, depending on the topology of the graph. An example of doubly additive scores in the analysis of a Burt subtable is given.
Interval Appendectomy after Conservative Treatment of an Appendiceal Mass
Authors: Lai Hung‐Wen , Loong Che‐Chuan , Chiu Jen‐Hwey , Chau Gar‐Yang , Wu Chew‐Wun , Lui Wing‐Yui 
Published: February 2006

AbstractIntroductionThe purpose of this study was to clarify the role of interval appendectomy after conservative treatment of an appendiceal mass.MethodsFrom January 1998 to December 2003, patients with an appendiceal mass who received conservative treatment at the Taipei Veterans General Hospital were studied retrospectively. Data on demographics, rate of appendicitis recurrence, duration of hospital stay, and complication rate were collected and analyzed.ResultsA total of 165 patients were included (89 males, 76 females). The mean age was 53.6 years (range 7–89 years). The rate of appendicitis recurrence after conservative treatment was 25.5%; most recurred within 6 months after discharge (83.3%). The benefit of preventing recurrence is less than 16% if interval appendectomy is performed 6 weeks after discharge and less than 10% if it is done 12 weeks later. The complication rate of appendectomy performed before or after recurrence was 10% in both groups. The duration of the second hospital stay for patients who underwent interval appendectomy before or after recurrence was 4.43 ± 3.32 vs. 6.75 ± 5.73 days (P = 0.023). Of the 165 patients, 17 (10.3%) had their diagnosis changed after survey or surgery, and 5 (3.03%) were found to have colon cancer upon follow‐up.ConclusionsPatients who recovered from conservative treatment of an appendiceal mass should undergo colonoscopy or barium enema to detect any underlying diseases and to rule out coexistent colorectal cancer. Routine interval appendectomy benefits less than 20% of patients.
Randomized Controlled Trial of LigaSure with Submucosal Dissection versus Ferguson Hemorrhoidectomy for Prolapsed Hemorrhoids
Authors: Wang Jaw‐Yuan , Lu Chien‐Yu , Tsai Hsiang‐Lin , Chen Fang‐Ming , Huang Che‐Jen , Huang Yu‐Sheng , Huang Tsung‐Jen , Hsieh Jan‐Sing 
Published: February 2006

AbstractIntroductionThe aim of this study was to compare the outcomes between the LigaSure vessel sealing system and the conventional closed Ferguson hemorrhoidectomy procedure performed by diathermy.MethodsA series of 84 patients with grades III and IV hemorrhoids were randomized into two groups: (1) LigaSure hemorrhoidectomy with submucosal dissection (42 patients) and (2) Ferguson hemorrhoidectomy (42 patients). The patient demographics, operative details, parenteral analgesic requirement, postoperative pain score (assessed by an independent assessor), operating time, intraoperative blood loss, hospital stay, early and delayed complications, and time off from work or normal activity were recorded. The patients were regularly followed up at 1, 2, 4, 6, and 8 weeks after surgery.ResultsThere were no statistically significant differences between the two groups in terms of age, gender, duration of symptoms, grade of the hemorrhoid(s), or number of hemorrhoids resected. The mean operating time for LigaSure hemorrhoidectomy with submucosal dissection was significantly shorter than that for the Ferguson hemorrhoidectomy (11.3 ± 0.4 vs. 34.2 ± 0.7 minutes; P < 0.0001). Patients treated with the LigaSure method had significantly less blood loss (P < 0.0001), a better pain score (P < 0.0001), less parenteral analgesic requirement (P < 0.0001), shorter hospital stay (P < 0.0001), and less time off from work or normal activity (P < 0.0001). There was no difference in the early and delayed postoperative complications between the two groups.ConclusionsLigaSure hemorrhoidectomy with submucosal dissection is a safe, effective procedure for grade III and IV hemorrhoids. Patients derive greater short‐term benefits: reduced intraoperative blood loss, operating time, and postoperative pain as well as earlier resumption of work or normal activity. Long‐term follow‐up with a larger number of patients is required to confirm the long‐term results of this procedure.
Carbon Dye Staining of Sentinel Lymph Nodes Facilitates Microstaging of Colon Cancer Patients
Authors: Viehl Carsten T. , Guller Ulrich , Hamel Christian T. , Riehle Hans‐Martin , Plaass Christian , Marti Walter R. , Oertli Daniel , Zuber Markus 
Published: February 2006

AbstractBackgroundCarbon dye, when peritumourally injected, permanently marks the drainage site of sentinel lymph nodes (SLN). The objective of the current study was to evaluate whether the use of carbon dye facilitated the detection of small nodal tumour infiltrates in colon cancer patients.MethodsIn a prospective trial, 19 patients underwent open, oncological resections of localized colon cancer and SLN procedure according to a standardized protocol. Isosulfan blue 1% and sterile filtered carbon dye (mixed 1:1) were injected into the subserosa circumferentially around the tumour. Lymph nodes staining blue were marked as SLN. Serial sections of each SLN were stained with hematoxylin and eosin (H&E) and with the pancytokeratin marker AE1/AE3. The intranodal presence and site of carbon particles were noted and compared with the location of possible tumour infiltrates.ResultsIdentification of at least one SLN was successful in 18 patients (identification rate 95%). Four patients (22%) were pN+, 11 (61%) were pN0(i−). Three patients (17%) were upstaged from pN0(i−) to pN0(i+) as isolated tumour cells were detected in their SLN: in two (11%) of the three patients, carbon dye and isolated tumour cells were found in the same nodal compartment, hence facilitating the recognition of isolated tumour cells by the pathologist.ConclusionThe use of carbon dye in the SLN procedure for colon cancer may facilitate the detection of small nodal tumour infiltrates.
Does Familial Non‐Medullary Thyroid Cancer Adversely Affect Survival?
Authors: Triponez Frederic , Wong Mariwil , Sturgeon Cord , Caron Nadine , Ginzinger David G. , Segal Mark R. , Kebebew Electron , Duh Quan‐Yang , Clark Orlo H. 
Published: February 2006

AbstractBackgroundFamilial non‐medullary thyroid cancer (FNMTC) is associated with a higher rate of multifocality and a higher recurrence rate than sporadic thyroid cancer. However, the effect of FNMTC on life expectancy is unknown.Material and MethodsUsing data from our FNMTC database, we calculated life expectancy and survival rates after diagnosis of FNMTC and compared the results with the rates for unaffected family members and for the standard US population. Overall life expectancy and survival rates were calculated using the Kaplan–Meier method. We compared patients from families with 2 affected members with patients from families with ≥3 affected members. We also compared patients diagnosed in a known familial setting (index cases and subsequent cases) with patients diagnosed before the familial setting was recognized.ResultsThere were 139 affected patients with 757 unaffected family members. The mean age at diagnosis was 40.8 ± 13.9 years and the mean follow‐up time was 9.4 ± 11.7 years. Ten patients died of thyroid cancer during follow‐up. The life expectancy of patients with FNMTC was similar to that of their unaffected family members. Survival was significantly shorter for patients with 3 or more affected family members, for patients diagnosed before the familial setting was recognized, and for patients with anaplastic cancer.ConclusionsOur results suggest that FNMTC may be more aggressive than sporadic thyroid cancer, particularly in families with 3 or more affected members. However, when recognized and treated appropriately, it does not significantly shorten the overall life expectancy of the affected patients.