bluuebunny/crossref_metadata_2025_split huggingface dataset:
Matrix‐free thin‐layer chromatography/laser desorption ionization mass spectrometry for facile separation and identification of medicinal alkaloids
Authors: Shariatgorji Mohammadreza , Spacil Zdenek , Maddalo Gianluca , Cardenas Lourdes B. , Ilag Leopold L. 
Published: November 2009

AbstractQuaternary protoberberine alkaloids belong to a pharmaceutically important class of isoquinoline alkaloids associated with bactericidal, fungicidal, insecticidal and antiviral activities. As traditional medicine gains wider acceptance, quick and robust analytical methods for the screening and analysis of plants containing these compounds attract considerable interest. Thin‐layer chromatography (TLC) combined with matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is a powerful technique but suffers from dilution of the TLC bands resulting in decreased sensitivity and masking of signals in the low‐mass region both due to addition of matrix. This study integrates for the first time conventional silica gel TLC and laser desorption ionization mass spectrometry (LDI‐MS) thus eliminating the need for any external matrix. Successful separation of berberine (Rf = 0.56) and palmatine (Rf = 0.46) fromBerberis barandanaincluding their identification by MS are demonstrated. Furthermore, a robust electrospray ionization (ESI)‐MS method utilizing residual sample from TLC for quantification of berberine applying selected reaction monitoring and standard addition method is presented. The amount of berberine in the plant root prepared for the study was determined to be 0.70% (w/w). Copyright © 2009 John Wiley & Sons, Ltd.
A novel high‐performance liquid chromatography/mass spectrometry method for improved selective and sensitive measurement of methotrexate polyglutamation status in human red blood cells
Authors: van Haandel Leon , Becker Mara L. , Leeder J. Steven , Williams Todd D. , Stobaugh John F. 
Published: November 2009

AbstractThe folate antagonist methotrexate is commonly used in low dose for treatment of rheumatoid arthritis and juvenile idiopathic arthritis. Therapeutic effects are attributed to intracellular levels of various methotrexate polyglutamates. The present methodology, combining a simple preparation step with ion‐pairing reversed‐phase liquid chromatography and electrospray ionization mass spectrometry, is suitable for the measurement of methotrexate and its polyglutamates2–7, in human red blood cells. Sample preparation consists of perchloric acid protein precipitation followed by solid‐phase extraction. Baseline separation of all analytes was achieved within 10 min using a Phenomenex Synergy C18 column together with a gradient solvent program obtained from blending acetonitrile with pH 7.5, 5 mM aqueous dimethylhexylamine. Seven methotrexate polyglutamates were detected using multiple reaction monitoring, with the mass spectrometer operating in positive ion mode. Using 20 µL injection volumes, limits of detection were 2.5 nM for individual methotrexate polyglutamates, while large volume (100 µL) injections led to detection limits of 0.5 nM and linear calibration from 0.5 to 100 nM for individual analytes. Finally, the presented methodology was applied for the analysis of methotrexate and its polyglutamates in red blood cells obtained from patients being treated for juvenile idiopathic arthritis with methotrexate. Significantly, the methodology proved suitable for determination of long‐chain methotrexate polyglutamates5–7 and further, appears to be superior with respect to sensitivity, selectivity and speed as compared to all previously described approaches. Copyright © 2009 John Wiley & Sons, Ltd.
Electrospray ionization mass spectrometry studies of cyclodextrin‐carboxylate ion inclusion complexes
Authors: Mohamed Mohamed H. , Wilson Lee D. , Headley John V. , Peru Kerry M. 
Published: November 2009

AbstractAqueous solutions containing simple model aliphatic and alicyclic carboxylic acids (surrogates 1–4) were studied using negative ion electrospray mass spectrometry (ESI‐MS) in the presence and absence of α‐, β‐, and γ‐cyclodextrin. Molecular ions were detected corresponding to the parent carboxylic acids and complexed forms of the carboxylic acids; the latter corresponding to non‐covalent inclusion complexes formed between carboxylic acid and cyclodextrin compounds (e.g., β‐CD, α‐CD, and γ‐CD). The formation of 1:1 non‐covalent inclusion cyclodextrin‐carboxylic complexes and non‐inclusion forms of the cellobiose‐carboxylic acid compounds was also observed.Aqueous solutions of Syncrude‐derived mixtures of aliphatic and alicyclic carboxylic acids (i.e. naphthenic acids; NAs) were similarly studied using ESI‐MS, as outlined above. Molecular ions corresponding to the formation of CD‐NAs inclusion complexes were observed whereas 1:1 non‐inclusion forms of the cellobiose‐NAs complexes were not detected. The ESI‐MS results provide evidence for some measure of inclusion selectivity according to the 'size‐fit' of the host and guest molecules (according to carbon number) and the hydrogen deficiency (z‐series) of the naphthenic acid compounds. The relative abundances of the molecular ions of the CD‐carboxylate anion adducts provide strong support for differing complex stability in aqueous solution. In general, the 1:1 complex stability according to hydrogen deficiency (z‐series) of naphthenic acids may be attributed to the nature of the cavity size of the cyclodextrin host compounds and the relative lipophilicity of the guest. Copyright © 2009 John Wiley & Sons, Ltd.
Changes in the natural abundance of 13CO2/12CO2 in breath due to lipopolysacchride‐induced acute phase response
Authors: Butz Daniel E. , Cook Mark E. , Eghbalnia Hamid R. , Assadi‐Porter Fariba , Porter Warren P. 
Published: November 2009

AbstractThe natural abundance of carbon‐13 in blood proteins increases during the cachectic state and may be a biomarker for disease status. We hypothesized a corresponding drop in the relative abundance of 13C in breath CO2. Using the lipopolysacchride (LPS)‐induced endotoxemia model of the acute cachectic state, we demonstrated that the acute phase response causes shifts in the stable isotopes of carbon in exhaled CO2 (13CO2/12CO2 delta value) shortly after administration of LPS while glucocorticoid treatment does not. Mice were injected with LPS and stable isotopes of blood amino acids and carbon in exhaled CO2 were monitored. An increase in the relative isotopic mass of serum alanine, proline and threonine was observed at 3 h after LPS injection. Breath delta values began dropping immediately after administration of LPS, and were 4–5 delta values lower than those of the control animals by 2.5 h after injection. A corresponding drop in delta value was not observed with dexamethasone treatment. Thus protein synthesis during the acute phase response probably caused the fractionation of stable isotopes observed in the plasma amino acids and in exhaled breath 13CO2 delta values. The exhaled breath 13CO2 delta value may be a valuable real‐time biomarker of cachexia associated with an acute phase response due to endotoxemia. Copyright © 2009 John Wiley & Sons, Ltd.
Species identification by analysis of bone collagen using matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry
Authors: Buckley Michael , Collins Matthew , Thomas‐Oates Jane , Wilson Julie C. 
Published: November 2009

AbstractSpecies identification of fragmentary bone, such as in rendered meat and bone meal or from archaeological sites, is often difficult in the absence of clear morphological markers. Here we present a robust method of analysing genus‐specific collagen peptides by mass spectrometry simply by using solid‐phase extraction (a C18 ZipTip®) for peptide purification, rather than liquid chromatography/mass spectrometry (LC/MS). Analysis of the collagen from 32 different mammal species identified a total of 92 peptide markers that could be used for species identification, for example, in processed food and animal feed. A set of ancient (>100 ka@10°C) bone samples was also analysed to show that the proposed method has applications to archaeological bone identification. Copyright © 2009 John Wiley & Sons, Ltd.
Metabolomics profiling of extracellular metabolites in recombinant Chinese Hamster Ovary fed‐batch culture
Authors: Chong William P. K. , Goh Lin Tang , Reddy Satty G. , Yusufi Faraaz N.K. , Lee Dong Yup , Wong Niki S. C. , Heng Chew Kiat , Yap Miranda G. S. , Ho Ying Swan 
Published: November 2009

AbstractA metabolomics‐based approach was used to time profile extracellular metabolites in duplicate fed‐batch bioreactor cultures of recombinant Chinese Hamster Ovary (CHO) cells producing monoclonal IgG antibody. Culture medium was collected and analysed using a high‐performance liquid chromatography (HPLC) system in tandem with an LTQ‐Orbitrap mass spectrometer. An in‐house software was developed to pre‐process the LC/MS data in terms of filtering and peak detection. This was followed by principal component analysis (PCA) to assess variance amongst the samples, and hierarchical clustering to categorize mass peaks by their time profiles. Finally, LC/MS2 experiments using the LTQ‐Orbitrap (where standard was available) and SYNAPT™ HDMS (where standard was unavailable) were performed to confirm the identities of the metabolites. Two groups of identified metabolites were of particular interest; the first consisted of metabolites that began to accumulate when the culture entered stationary phase. The majority of them were amino acid derivatives and they were likely to be derived from the amino acids in the feed media. Examples included acetylphenylalanine and dimethylarginine which are known to be detrimental to cell growth. The second group of metabolites showed a downward trend as the culture progressed. Two of them were medium components – tryptophan and choline, and these became depleted midway into the culture despite the addition of feed media. The findings demonstrated the potential of utilizing metabolomics to guide medium design for fed‐batch culture to potentially improve cell growth and product titer. Copyright © 2009 John Wiley & Sons, Ltd.
Global synchronization of complex dynamical networks with network failures
Authors: Wang Yan‐Wu , Xiao Jiang‐Wen , Wang Hua O. 
Published: November 2009

AbstractNetwork failure refers to the case that parts or all of the connections in the network become disconnected. In this paper, the global synchronization of complex dynamical networks with network failures is studied based on the framework of switching system. For simplicity, assume that the network becomes totally unavailable when network failures happen and it takes a period of time to fix the network. In order to ensure the global synchronization of CDNs with network failures, the upper bounds of both the unavailability rate of the network and the frequency of network failures are obtained, respectively. Illustrated examples and the simulation results also show the effectiveness of the proposed result. Copyright © 2009 John Wiley & Sons, Ltd.
Maneuverability and path following control of wheeled mobile robot in the presence of wheel skidding and slipping
Authors: Low Chang Boon , Wang Danwei 
Published: November 2009

AbstractThis paper addresses the path following control problem of wheeled mobile robots in the presence of wheel skidding and slipping. A conditional global positioning system (GPS)‐based path following controller is proposed for four generic WMRs to achieve high‐precision path following performance. The proposed controller utilizes real‐time kinematic‐GPS and other aiding sensors to determine the robot's pose and wheel skidding and slipping perturbations to achieve accurate path following control. The reported simulation and experimental results suggest that with this control scheme, the WMRs are able to maneuver with precision. © 2009 Wiley Periodicals, Inc.
Survival analysis with clustered observations of orthodontic brackets
Authors: Petracci Elisabetta , Farella Mauro , Galeone Carlotta , Albano Alessandra , Ferraroni Monica , Decarli Adriano 
Published: November 2009

AbstractFailures in the bonding of dental bracket are a big concern for orthodontists. Clinical experience suggests that some patients are more prone than others to experience failures. Therefore, it can be expected that in statistical analysis of orthodontic bracket failures, the usual assumption of independence between the observations is violated. An approach to overcome this problem is to apply the frailty model, in which the association between failure times is modelled with a random‐effect term (i.e. frailty). We postulated that brackets of the same subject share the same frailty, that is, a latent common group effect, due to some unknown or unobserved covariates.The aim of this study was to investigate possible risk factors related to bracket failure using Cox proportional hazards model with a shared frailty term and to compare the results with those obtained using a basic Cox proportional hazards model.Survival data for 1677 brackets were obtained from a cohort of 54 females (mean age ± SD: 13.3±4.8yrs) and 46 males (mean age ±SD: 13.1±3.8yrs) over a eight‐year period. Age, gender, vertical craniofacial morphology and anatomical location of brackets were entered into Cox models as covariates. The findings indicated that bracket failure was significantly affected by tooth position within the dental arch, with the highest failure risk in maxillary posterior region. Age, gender and vertical craniofacial morphology did not affect bracket failure. A Cox proportional hazards model with a shared frailty term represents a useful approach for modelling orthodontic bracket failures. Copyright © 2009 John Wiley & Sons, Ltd.
Flexibility of Bayesian generalized linear mixed models for oral health research
Authors: Berchialla Paola , Baldi Ileana , Notaro Vincenzo , Barone‐Monfrin Sandro , Bassi Francesco , Gregori Dario 
Published: November 2009

AbstractMany outcome variables in oral research are characterized by positive values and heavy skewness in the right tail. Examples are provided by many distributions of dental variables such as DMF (decayed, missing, filled teeth) scores, oral health impact profile score, gingival index scores, and microbiologic counts. Moreover, heterogeneity in data arises when more than one tooth is studied for each patient, due to the clusterization.Over the past decade, linear mixed models (LMEs) have become a common statistical tool to account for within‐subject correlation in data with repeated measures. When a normal error is reasonably assumed, estimates of LMEs are supported by many statistical packages. Such is not the case for skewed data, where generalized linear mixed models (GLMMs) are required. However, the current software available supports only special cases of GLMMs or relies on crude Laplace‐type approximation of integrals. In this study, a Bayesian approach is taken to estimate GLMMs for clustered skewed dental data. A Gamma GLMM and a log‐normal model are employed to allow for heterogeneity across clusters, deriving from the patient‐operator‐tooth susceptibility typical of this clinical context. A comparison to the frequentist framework is also provided. In our case, Gamma GLMM fits data better than the log‐normal distribution, while providing more precise estimates compared with the likelihood approach. A key advantage of the Bayesian framework is its ability to readily provide a flexible approach for implementation while simultaneously providing a formal procedure for solving inference problems. Copyright © 2009 John Wiley & Sons, Ltd.
Modelling count data with excessive zeros: The need for class prediction in zero‐inflated models and the issue of data generation in choosing between zero‐inflated and generic mixture models for dental caries data
Authors: Gilthorpe Mark S. , Frydenberg Morten , Cheng Yaping , Baelum Vibeke 
Published: November 2009

AbstractCount data may possess an ‘excess’ of zeros relative to standard distributions. Zero‐inflated Poisson (ZiP) or binomial (ZiB) and generic mixture models have been proposed to deal with such data. We consider biomedical count data with an excess number of zeros and seek to address the following: (i) do zero‐inflated models need covariates in the distribution part to predict class membership; (ii) what model‐fit criteria have clinical relevance to predicted counts; (iii) can very different model parameterizations have near‐identical fit; and (iv) how could model selection and hence model interpretation be aided by considering data generation processes? We show that covariates in the distribution part of zero‐inflated models are needed to predict class membership. A range of model‐fit criteria should be considered, as consensus is rarely achieved, and considering predicted outcomes may be just as valuable as likelihood‐based criteria. Zero‐inflated and generic mixture models may be indistinguishable according to both likelihood‐based model‐fit criteria and predicted outcomes, in which case model differentiation, hence, model selection and interpretation, might be guided by the consideration of a priori data generation processes. Zero‐inflated models reflect whether or not there are (or have been) risk differences in disease onset and disease progression, while generic mixture models identify sub‐types of individuals with similar risks of disease onset and progression. One or both modelling strategies may be used, though a priori knowledge or clinical impression of data generation might help to distinguish between two or more parameterizations that exhibit similar fit and yield near‐identical predicted counts. Copyright © 2009 John Wiley & Sons, Ltd.
Ultrasound monitoring in patients undergoing in‐vitro fertilization after methotrexate treatment for ectopic pregnancy
Authors: Provansal M. , Agostini A. , Lacroix O. , Gerbeau S. , Grillo J.‐M. , Gamerre M. 
Published: November 2009

AbstractObjectivesTo compare sonographic characteristics of the endometrium and follicles during in‐vitro fertilization (IVF) before and after methotrexate (MTX) treatment for ectopic pregnancy.MethodsThis retrospective study, conducted at Conception Hospital from January 2000 to July 2007, included all patients diagnosed with an ectopic pregnancy resulting from IVF treatment that was treated with MTX and who then underwent another IVF cycle. We compared the number and size of follicles and the endometrial thickness and quality on the day of human chorionic gonadotropin injection in the cycles before and after the MTX treatment to determine whether MTX had any effect.ResultsEleven patients were included in the study. The median interval between the IVF cycle resulting in ectopic pregnancy and the first IVF cycle after MTX therapy was 180 (range, 150–900) days. There was no statistically significant difference between the before and after MTX treatment groups with respect to number of follicles (14 (3–20) vs. 9 (4–16), P = 0.12), follicle size (16.5 (14.7–21.7) mm vs. 17.8 (14.9–19.8) mm, P = 0.37), endometrial thickness (10.0 (9.5–12.0) mm vs. 10.0 (7.5–14.0) mm, P = 0.31) or endometrial quality (P = 0.32). Four women became pregnant during the IVF cycle following MTX treatment.ConclusionsUltrasound monitoring showed no modification of the characteristics of the endometrium or follicles during IVF after MTX treatment for ectopic pregnancy. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Gel infusion sonography in the evaluation of the uterine cavity
Authors: Van den Bosch T. , Betsas G. , Van Schoubroeck D. , Daemen A. , Vandenbroucke V. , Cornelis A. , De Moor B. , Deprest J. , Timmerman D. 
Published: November 2009

AbstractObjectivesTo compare gel infusion sonohysterography (GIS) with saline contrast sonohysterography (SCSH) with regard to technical feasibility and procedure‐related pain experienced by patients.MethodsThis prospective observational cohort study included 551 consecutive patients with abnormal bleeding: SCSH was attempted in the first 402 women and GIS was attempted in the following 149. All procedures were performed by the same examiner, in the same clinical setting, using a 2‐mm diameter catheter. After contrast sonohysterography, most patients underwent office hysteroscopy (n = 502) and endometrial sampling (n = 323). The women were asked to rate the pain experienced during each procedure using a 100‐mm visual analog scale (VAS). Patients' characteristics, ultrasound findings, histological diagnosis, technical failures and procedure‐related pain were compared between the two procedures.ResultsThe mean ± SD VAS score for contrast sonography, subsequent hysteroscopy and endometrial biopsy were 22.9 ± 21.7, 38.8 ± 26.6 and 50.0 ± 26.3, respectively, in the SCSH subgroup vs. 16.5 ± 21.5, 27.6 ± 28 and 33.6 ± 30.3, respectively, in the GIS subgroup (P = 0.0051, P = 0.0005 and P = 0.0003, respectively). The technical failure rate was 5% in the SCSH subgroup vs. 2% in the GIS subgroup (P = 0.1522).ConclusionsGIS and SCSH showed similar technical feasibility. The procedure‐related pain reported by patients during contrast sonohysterography, as well as during subsequent hysteroscopy and endometrial sampling, was less in the GIS group. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Profiling Capacity for Coordination and Systems Change: The Relative Contribution of Stakeholder Relationships in Interorganizational Collaboratives
Authors: Nowell Branda 
Published: November 2009

AbstractIn response to increasing demands for greater coordination and collaboration among community institutions, interorganizational collaboratives (i.e., coalitions, partnerships, coordinating councils) have emerged as a popular mechanism for strengthening the capacity of a community system to respond to public and social issues. This study adopts a network approach to explore the relative importance of dense networks of cooperative relationships among members of interorganizational collaboratives for two outcomes of effectiveness: improving interorganizational coordination and fostering systems change. Based on survey and social network data collected from 48 different collaboratives, findings indicate that, relative to other key characteristics of collaboratives identified in previous literature, cooperative stakeholder relationships were the strongest predictor of systems change outcomes. However, for coordination outcomes, stakeholder relationships were overshadowed in importance by the leadership and decision making capacity of the collaborative. Collectively, findings suggest key differences in the requisite capacity profiles for coordination and systems change outcomes.
Women's Perceptions of the Personal and Family Impact of Genetic Cancer Risk Assessment: Focus Group Findings
Authors: MacDonald Deborah J. , Sarna Linda , Weitzel Jeffrey N. , Ferrell Betty 
Published: November 2009

AbstractWomen with a personal or family history of breast or ovarian cancer are increasingly presenting for genetic cancer risk assessment (GCRA). To explore the personal and family impact of GCRA, four focus groups were conducted of women seen for risk assessment. Participants were 22 primarily non‐Latina White women with a personal or family history of breast or ovarian cancer. Analysis of the data identified new themes related to balancing time to assimilate risk information with the need to make timely healthcare decisions, physicians’ lack of sufficient genetic knowledge, and concern for daughters regardless of the daughters’ age. Other themes related to protecting others, knowledge as empowerment, reassessing personal attribution of cancer risk, managing uncertainty, reappraising body image, and experiencing divergent family responses to communication of cancer risk and healthcare decisions. Understanding the personal and family impact of GCRA may enable genetics professionals to tailor their counseling efforts to better meet the needs of these women. Additional research is needed to extend these findings and identify interventions to support positive outcomes of GCRA.